From c8cd40992449e32b5d28f046e6c5278d20baadc1 Mon Sep 17 00:00:00 2001 From: Aptivi Date: Mon, 1 Apr 2024 10:53:15 +0300 Subject: [PATCH] add - Added vCalendar specs --- We've added just the specifications for vCalendar. However, we won't implement it in this version of VisualCard, because this version focuses on the core functionality only. However, in a future release, we may implement it in a limited form which will then get improved from time to time until we reach version 2.0 of VisualCard. --- Type: add Breaking: False Doc Required: False Part: 1/1 --- VisualCard/Specs/vcalendar-10.txt | 1602 ++++ VisualCard/Specs/vcalendar-20-rfc5545.txt | 9411 +++++++++++++++++++++ 2 files changed, 11013 insertions(+) create mode 100644 VisualCard/Specs/vcalendar-10.txt create mode 100644 VisualCard/Specs/vcalendar-20-rfc5545.txt diff --git a/VisualCard/Specs/vcalendar-10.txt b/VisualCard/Specs/vcalendar-10.txt new file mode 100644 index 0000000..a6f12fd --- /dev/null +++ b/VisualCard/Specs/vcalendar-10.txt @@ -0,0 +1,1602 @@ +vCalendar +The Electronic Calendaring and Scheduling +Exchange Format +Version 1.0 + +A versit Consortium Specification +September 18, 1996 + +Copyrights +©, 1996, International Business Machines Corp., Lucent Technologies, Inc., and Siemens. All rights reserved. +Permission is granted to copy and distribute this publication provided that it is reproduced in its entirety without modification and includes the above copyright notice and this permission notice. +No licenses, express or implied, are granted with respect to any of the technology described in this publication. International Business Machines Corp., Lucent Technologies, Inc., and Siemens retain all their intellectual property rights in the technology described in this publication. +Even though International Business Machines Corp., Lucent Technologies, Inc., and Siemens have reviewed this specification, INTERNATIONAL BUSINESS MACHINES CORP., LUCENT TECHNOLOGIES, INC., AND SIEMENS, MAKE NO WARRANTY OR REPRESENTATION, EITHER EXPRESS OR IMPLIED, WITH RESPECT TO THIS PUBLICATION, ITS QUALITY OR ACCURACY, NONINFRINGEMENT, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE. AS A RESULT, THIS SPECIFICATION IS DELIVERED "AS IS" AND THE READER ASSUMES THE ENTIRE RISK AS TO ITS QUALITY, ACCURACY OR SUITABILITY FOR ANY PARTICULAR PURPOSE.. +IN NO EVENT WILL INTERNATIONAL BUSINESS MACHINES CORP., LUCENT TECHNOLOGIES, INC., AND SIEMENS, BE LIABLE FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RESULTING FROM ANY DEFECT OR INACCURACY IN THIS PUBLICATION, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. +This publication is provided with RESTRICTED RIGHTS. Use, duplication, or disclosure by the Government are subject to restrictions set forth in DFARS 252.227-7013 or 48 CFR 52.227-19, as applicable. + +Trademarks +versit, the versit logo, versitcard, vCard, vCalendar are trademarks of Apple Computer, Inc., AT&T Corp., International Business Machines Corp., and Siemens. +Apple and the Apple Logo are trademarks of Apple Computer, Inc. registered in the U.S. and other countries. +AT&T is a registered trademarks of AT&T Corp. +IBM is a registered trademarks of International Business Machines Corporation. + +Contributors +Roland H. Alden +Stephen J. Bartlett + +Jay Batson, ON Technology +John Binici, Iris Associates + +Steve Carter, Novell +Liang-Jye Chang, Starfish Software + +Andre Courtemanche, CS&T +Jim Cunnie, AT&T EasyCommerce + +Frank Dawson, IBM Corporation +Rik Drummond, The Drummond Group + +Gavin Eadie, University of Michigan +Pat Egen, Provident Life and Accident + +Randell Flint, Sundial Systems +Ben Forta, OnTime/Division of FTP + +Anik Ganguly, OnTime/Division of FTP. +Arvind Goyal, Lotus Development Corporation + +David Goodhand, Microsoft +Steve Hanna, ON Technology + +John Hansen, Starfish Software +Niraj Jain, Oracle Corporation + +Del Jensen, Novell +Bruce M. Johnston, Lotus Development Corporation + +Dr. Mark K. Joseph, Attachmate Corporation +Bruce Kahn, Iris Associates + +Don Lavange, Novell +Larry Mason, Microsystems Software, Inc. + +Skip Montanaro, Automatrix, Inc. +Pete OíLeary, Clear Blue Networking Systems, Inc. + +Ron Rassner, Creative Networks, Inc. +Vinod Seraphin, Lotus Development Corporation + +Uppili Srivivasan, Oracle Corporation +Tom Steppe, OnTime/Divison of FTP Software + +Dean Stevens, Now Software, Inc. +Budi Sutardja + +Robert Tatar, Automatrix, Inc. +Yvonne Tso, SunSoft + +Mike Weston, Netscape Communications Corporation. +Steve Wincor, Lockheed Martin + + + +Reference Information +The cited references contain provisions which, through reference in this specification, constitute provisions of this specification. At the time of publication, the indicated versions in the following references were valid. Parties to agreements based on this specification are encouraged to research the possibility of revised standards. +ï ANSI X3.4-1977, Code for Information Interchange, American National Standards Institute, 1977. +* IETF RFC 1738, Universal Resource Locator, December 1994. +* IETF Network Working Group RFC 1766, Tags for the Identification of Languages, March 1995. +* ISO 639, Code for The Representation of names of languages, International Organization for Standardization, April, 1988. +* ISO 3166, Codes for The Representation of names of countries, International Organization for Standardization, December, 1993. +* ISO 8601, Data elements and interchange formats-Information interchange-Representation of dates and times, International Organization for Standardization, June, 1988. +* ISO 8601, Technical Corrigendum 1, Data elements and interchange formats-Information interchange-Representation of dates and tmes, International Organization for Standardization, May, 1991. +* ISO 8859-1, Information Processing-8-Bit single-byte coded graphic character sets-Part 1: Latin Alphabet No. 1, International Organization for Standardization, February, 1987. +* ISO/IEC 9070, Information Technology-SGML Support Facilities-Registration Procedures for Public Text Owner Identifiers, Second Edition, International Organization for Standardization, April, 1991. +* RFC1521, MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies, Network Working Group, September, 1993. +* XAPIA CSA, Calendaring and Scheduling Application Programming Interface (CSA) Version 1.0, X.400 API Association, November 15, 1994. + + +versit Update +versit is a multivendor development initiative of the communication and computer industries, founded by Apple, AT&T, IBM and Siemens. The versit parties believe that great potential exists in improving the nature of communications in the business world-permitting companies to better manage their quality, productivity, customer satisfaction and cost of operations, while expanding the market opportunities for a variety of product and service vendors. versit parties will jointly define and support open specifications that facilitate and promote the interoperability of advanced personal information and communication devices, networks and services. +The versit vision is to enable diverse communication and computing devices, applications and services from competing vendors to interoperate in all environments. Through developing a series of specifications for interoperability among diverse communications and computing devices, applications, networks and services, versit 's vision will become a reality. +versit 's primary development areas are in: +* Personal Data Interchange (PDI) +* Computer Telephone Integration (CTI) +* Conferencing and Messaging (C&M) +* Wired and Wireless connectivity +versit specifications are directed at both the decision makers and the implementation teams of: +* Equipment Manufacturers +* Independent Software Vendors +* Information Service Providers +* Online Service Providers +* Software Houses +* Users +versit specifications are made available to any interested party. In turn, versit encourages the support of our goals by soliciting feedback on versit specifications. +All comments relating to versit or the material within this specification should be submitted to: +versit +(800) 803-6240 +(201) 327-2803 (Outside USA) +pdi@versit.com +http://www.versit.com + + +Contents +Section 1 : Introduction +1.1 Overview +1.2 Scope +1.3 Contents +1.4 Definitions and Abbreviations +Section 2 : vCalendar +2.1 Encoding Characteristics +2.1.1 vCalendar Object +2.1.1.1 vEvent Object +2.1.1.2 vTodo Object +2.1.2 Property +2.1.3 Delimiters +2.1.4 Encodings +2.1.5 Character Set +2.1.6 Language +2.1.7 Date and Time +2.1.8 Time Duration +2.1.9 Value Location +2.1.10 Binary Values +2.1.11 Basic Recurrence Rule Grammar +2.1.11.1 Daily Rule +2.1.11.2 Weekly Rule +2.1.11.3 Monthly Rule +2.1.11.4 Yearly Rule +2.1.11.5 Grammar +2.1.11.6 Glossary +2.1.11.7 Policies +2.2 vCalendar Properties +2.2.1 Daylight Savings Rule +2.2.2 Geographic Position +2.2.3 Product Identifier +2.2.4 Time Zone +2.2.5 Version +2.3 vEvent and vTodo Properties +2.3.1 Attachment +2.3.2 Attendee +2.3.3 Audio Reminder +2.3.4 Categories +2.3.5 Classification +2.3.6 Date/Time Created +2.3.7 Date/Time Completed +2.3.8 Description +2.3.9 Display Reminder +2.3.10 Due Date/Time +2.3.11 End Date/Time +2.3.12 Exception Date/Times +2.3.13 Exception Rule +2.3.14 Last Modified +2.3.15 Location +2.3.16 Mail Reminder +2.3.17 Number Recurrences +2.3.18 Priority +2.3.19 Procedure Reminder +2.3.20 Related To +2.3.21 Recurrence Date/Times +2.3.22 Recurrence Rule +2.3.23 Resources +2.3.24 Sequence Number +2.3.25 Start Date/Time +2.3.26 Status +2.3.27 Summary +2.3.28 Time Transparency +2.3.29 Uniform Resource Locator +2.3.30 Unique Identifier +2.4 Miscellaneous Properties +2.4.1 Extensions +2.5 Formal Definition +Section 3 : Internet Recommendations +3.1 Recommended Practice With SMTP/MIME +3.1.1 Text/Plain Content Type +3.1.2 Text/X-vCalendar Content Type +3.2 Recommended Practice With HTTP/HTML +Section 4 : UI Support Recommendations +4.1 File System +4.2 Clipboard +4.3 Drag/Drop +Section 5 : Conformance +Section 6 : Extended Recurrence Grammar +6.1 Rule Introduction +6.2 Grammar +6.3 Glossary +6.4 Policies +6.5 Examples + + +Section 1 : Introduction +[DS1] +Personal Data Interchange (PDI) occurs every time two or more individuals communicate, in either a business or personal context, face-to-face, or across space and time. Such interchanges frequently include the exchange of informal information, such as business cards, telephone numbers, addresses, dates and times of appointments, etc. Augmenting PDI with electronics and telecommunications can help ensure that information is quickly and reliably communicated, stored, organized and easily located when needed. +Personal information, by nature, is complex and diverse. Currently, proprietary standards exist to structure some types of PDI information, but no single, open specification comprehensively addresses the needs of collecting and communicating PDI information across many common communication channels such as telephones, voice-mail, e-mail, and face-to-face meetings. versit is developing a comprehensive family of PDI technologies based on open specifications and interoperability agreements to help meet this technology need. +Overview +This specification defines a format for an electronic calendaring and scheduling (vCalendar) format. The vCalendar format allows for the capture of information normally stored within a calendaring and scheduling application; such as a Personal Information Manager or a Group Scheduling product. +The format is suitable as an interchange format between applications or systems. The format is defined independent of the particular method used to transport it. The transport for this exchange might be a file system, point-to-point asynchronous communication, wired-network transport, or some form of unwired transport. +A vCalendar is a data stream consisting of one or more vCalendar objects. The individual vCalendar definitions can be identified and parsed within the data stream. The vCalendar data stream may exist as a persistent form in a file system, document management system, network connection between two network endpoints, or in any other digital transport that has an abstraction of a stream of bytes. +Conceptually, a vCalendar Writer creates vCalendar data streams and a vCalendar Reader interprets vCalendar data streams. The vCalendar Reader and Writer may be implemented as a single application or as separate applications. It is not the intent of this specification to define the implementation of these processes beyond some fundamental capabilities related to the format of the vCalendar data stream and a common set of conformance requirements. +This specification provides for a clear-text encoding. The specification also includes a formal grammar for the clear-text encoding to aid in the implementation of parsers and to serve as the definitive reference when ambiguities or questions arise in interpreting the descriptive prose definition of the specification. +The clear-text encoding of this specification can be used in environments which are constrained to 7-bit transfer encodings, short line lengths, and low bandwidth. In addition, the encoding is simple in order to facilitate the implementation of reader and writer applications on small platforms, such as Personal Digital Assistants (PDA), cellular telephones, or alphanumeric pagers. +Scope +The vCalendar is intended to be used for exchanging information about event and todo types of calendaring and scheduling entities. An event is a calendaring and scheduling entity that represents a scheduled amount of time on a calendar. For example, it may be an activity; such as a one-hour, department meeting from 8 AM to 9 AM, tomorrow. A todo is a calendaring and scheduling entity that represents an action-item or assignment. For example, it may be an item of work assigned to an individual; such as "turn in travel expense today". +In today's business environment, this information is typically kept on a paper-based day-planner or calendar. More and more, this type of information is being also managed within electronic Personal Information Manager or Group Scheduling products. It is appropriate, then that this specification define this information in terms of a paradigm based on a calendaring and scheduling event and todo entities. +Prior to the introduction of the vCalendar specification, users of such applications typically had to re-key the original information, often transcribing it from paper day-planners, scraps of paper or electronic mail messages. With the advent of the vCalendar specification, this information can be exchanged in an automated and consistent fashion. +The basis for this specification have their origin in openly defined, industry specifications; such as the X.400 API Association's Calendaring and Scheduling API (CSA). In addition, this specification has capabilities that were derived from the experience of multi-vendor demonstrations of this capability. +The specification of all date and time values are defined in terms of the ISO 8601 standard for representation of dates and times. The ISO 8601 standard supersedes all other international standards defined at the time this specification was drafted. +Personal data applications such as Personal Information Managers (PIM) often provide an import/export capability using Comma Separated Value (CSV) or Tab Delimited Files (TDF) formats. However, these solutions do not preserve the intent of the originating application. When a CSV and TDF format is used by a PIM, the meta-data or semantics of the originating object are only apparent to a similar version of the originating application. Exchange of data between such applications is another important application of an industry-standard specification for an electronic calendaring and scheduling interchange format, such as the vCalendar specification. +This specification is intended to be used as a format for exchange of calendaring and scheduling information from one product to another. This exchange may take place using desktop application interaction techniques; such as a file system FILE-OPEN or FILE-SAVE-AS functions, an operating systems clipboard CUT or COPY or PASTE operations, or a user interface DRAG and DROP interaction. In addition, this exchange may take place using a wired or wireless network transport; such as LAN or WAN protocols, switched telephone circuits, IrDA-based infra-red "beaming" of data, or emerging cellular data services. In any of these example cases, the vCalendar format is intended to be a transport- and platform-independent format for exchanging calendaring and scheduling personal data. +Contents +This specification is separated into eight sections: +* "Section 1 : Introduction" introduces PDI and the vCalendar specification with an overview, scope statement and section on definitions and abbreviations. +* "Section 2 : vCalendar" defines the semantics and syntax for a clear-text encoding of the vCalendar. +* "Section 3: Internet Recommendations" specifies a set of guidelines to facilitate the exchange of vCalendar objects over Internet protocols such as HTTP using HTML and SMTP using MIME. +* "Section 4 : UI Support Recommendations" specifies a set of guidelines to facilitate the exchange of vCalendar objects at the desktop user interface using the file system, clipboard and drag/drop capabilities of the operating system. +* "Section 5 : Conformance" defines minimum conformance requirements to consider while developing support for this vCalendar specification. +* "Section 6 : Extended Recurrence Rule Grammar" defines reference information on an extended recurrence rule grammar, copied from the XAPIA CSA Specification. +Definitions and Abbreviations +Definitions and abbreviations used within this specification follow. +API: Application Programming Interface +Electronic Calendar: Also know as vCalendar. +FPI: Formal Public Identifier. A string expression that represents a public identifier for an object. FPI syntax is defined by ISO 9070. +GUID: Globally Unique IDentifier +Internet: A WAN connecting thousands of disparate networks in industry, education, government, and research. The Internet uses TCP/IP as the standard for transmitting information. +ISO: Organization for International Standardization; a worldwide federation of national standards bodies (ISO Member bodies). +MIME: Multipurpose Internet Mail Extensions, as defined in RFC1521. +PDA: Personal Digital Assistant computing device +PDI: Personal Data Interchange, a collaborative application area which involves the communication of data between people who have a business or personal relationship, but do not necessarily share a common computing infrastructure. +PIM: Personal Information Manager +RFC### documents: Internet "Request For Comment" documents (i.e., RFC822, RFC1521, etc.). +URL: Uniform Resource Locator; a string expression that can represent any resource on the Internet or local system. RFC 1738 defines the syntax for an URL. +UTC: Universal Time Coordinated; also known as UCT, for Universal Coordinated Time. +vCalendar: The generic term for an electronic, virtual collection of calendaring and scheduling information that can be transferred between computers, PDAs, or other electronic devices through telephone lines, or e-mail networks, or infrared links. How, when, why, and where vCalendar are used depends on the applications developed utilizing a vCalendar. +WAN: Wide-Area Network + + +Section 2 : vCalendar +[DS2] +This section defines the semantics and syntax for encoding the vCalendar in a simple, clear-text encoding. +Encoding Characteristics +The following characteristics are specific to this encoding. +vCalendar Object +A vCalendar data stream may include one or more vCalendar objects. An individual vCalendar object is identified within a data stream by the appearance of the Begin vCalendar Delimiter: +BEGIN:VCALENDAR +The sentinel string must appear as the first characters in the data stream or the first characters on a line. +The vCalendar object is terminated by the appearance of the End vCalendar Delimiter as the first characters on a line: +END:VCALENDAR +The vCalendar object is a container for calendaring and scheduling entities. These can include either event or todo entities. +vEvent Object +A vEvent is a grouping of calendaring and scheduling properties that define an entity that represents a scheduled amount of time on a calendar. For example, it may be an activity; such as a one-hour, department meeting from 8 AM to 9 AM, tomorrow. +An individual vEvent entity is identified within a vCalendar object by the appearance of the delimiter: +BEGIN:VEVENT +The sentinel string must appear as the first characters on a line. +The vEvent entity is terminated with the appearance of the following delimiter string as the first characters on a line +END:VEVENT +The vEvent entity can not be nested within another vEvent or vTodo entity. If vEvent entities need to be related to each other or to a vTodo entity, they can specify relationship with the RELATED-TO property. +vTodo Object +A vTodo is a grouping of calendaring and scheduling properties that define an entity that represents an action-item or assignment. For example, it mayto 7-bit transfer encodings, short line lengths, and low bandwidth. In addition, the encoding is simple in order to facilitate the implementation of reader and writer applications on small platforms, such as Personal Digital Assistants (PDA), cellular telephones, or alphanumeric pagers. +Scope +The vCalendar is intended to be used for exchanging information about event and todo types of calendaring and scheduling entities. An event is a calendaring and scheduling entity that represents a scheduled amount of time on a calendar. For example, it may be an activity; such as a one-hour, department meeting from 8 AM to 9 AM, tomorrow. A todo is a calendaring and scheduling entity that represents an action-item or assignment. For example, it may be an item of work assigned to an individual; such as "turn in travel expense today". +In today's business environment, this information is typically kept on a paper-based day-planner or calendar. More and more, this type of information is being also managed within electronic Personal Information Manager or Group Scheduling products. It is appropriate, then that this specification define this information in terms of a paradigm based on a calendaring and scheduling event and todo entities. +Prior to the introduction of the vCalendar specification, users of such applications typically had to re-key the original information, often transcribing it from paper day-planners, scraps of paper or electronic mail messages. With the advent of the vCalendar specification, this information can be exchanged in an automated and consistent fashion. +The basis for this specification have their origin in openly defined, industry specifications; such as the X.400 API Association's Calendaring and Scheduling API (CSA). In addition, this specification has capabilities that were derived from the experience of multi-vendor demonstrations of this capability. +The specification of all date and time values are defined in terms of the ISO 8601 standard for representation of dates and times. The ISO 8601 standard supersedes all other international standards defined at the time this specification was drafted. +Personal data applications such as Personal Information Managers (PIM) often provide an import/export capability using Comma Separated Value (CSV) or Tab Delimited Files (TDF) formats. However, these solutions do not preserve the intent of the originating application. When a CSV and TDF format is used by a PIM, the meta-data or semantics of the originating object are only apparent to a similar version of the originating application. Exchange of data between such applications is another important application of an industry-standard specification for an electronic calendaring and scheduling interchange format, such as the vCalendar specification. +This specification is intended to be used as a format for exchange of calendaring and scheduling information from one product to another. This exchange may take place using desktop application interaction techniques; such as a file system FILE-OPEN or FILE-SAVE-AS functions, an operating systems clipboard CUT or COPY or PASTE operations, or a user interface DRAG and DROP interaction. In addition, this exchange may take place using a wired or wireless network transport; such as LAN or WAN protocols, switched telephone circuits, IrDA-based infra-red "beaming" of data, or emerging cellular data services. In any of these example cases, the vCalendar format is intended to be a transport- and platform-independent format for exchanging calendaring and scheduling personal data. +Contents +This specification is separated into eight sections: +* "Section 1 : Introduction" introduces PDI and the vCalendar specification with an overview, scope statement and section on definitions and abbreviations. +* "Section 2 : vCalendar" defines the semantics and syntax for a clear-text encoding of the vCalendar. +* "Section 3: Internet Recommendations" specifies a set of guidelines to facilitate the exchange of vCalendar objects over Internet protocols such as HTTP using HTML and SMTP using ject XYZ Final Review +Conference Room - 3B +Come Prepared. +Would be represented in a Quoted-Printable encoding as: +DESCRIPTION;ENCODING=QUOTED-PRINTABLE:Project XYZ Final Review=0D=0A= + Conference Room - 3B=0D=0A= + Come Prepared. +Property parameter substrings are delimited by a field delimiter, specified by the Semi-colon character (ASCII decimal 59). A Semi-colon in a property parameter value must be escaped with a Backslash character (ASCII 92). +Compound property values are delimited by a field delimiter, specified by the Semi-colon character (ASCII decimal 59). A Semi-colon in a component of a compound property value must be escaped with a Backslash character (ASCII 92). +Encodings +The default encoding for the vCalendar object is 7-Bit. The default encoding can be overridden for an individual property value by using the "ENCODING" property parameter. This parameter value can be either "BASE64", "QUOTED-PRINTABLE", or "8-bit". This parameter may be used on any property. +Some transports (e.g., MIME based electronic mail) may also provide an encoding property at the transport wrapper level. This property can be used in these cases for transporting a vCalendar data stream that has been defined using a default encoding other than 7-bit (e.g., 8-bit). +Character Set +The default character set is ASCII. The default character set can be overridden for an individual property value by using the "CHARSET" property parameter. This property parameter may be used on any property. However, the use of this parameter on some properties may not make sense. +Any character set registered with the Internet Assigned Numbers Authority (IANA) can be specified by this property parameter. For example, ISO 8859-8 or the Latin/Hebrew character set is specified by: +DESCRIPTION;CHARSET=ISO-8859-8:... +Some transports (e.g., MIME based electronic mail) may also provide a character set property at the transport wrapper level. This property can be used in these cases for transporting a vCalendar data stream that has been defined using a default character set other than ASCII (e.g., UTF-8). +Language +The default language is "en-US" (US English). The default language can be overridden for an individual property value by using the "LANGUAGE" property parameter. The values for this property are a string consistent with RFC 1766, Tags for the Identification of Languages. This property parameter may be used on any property. However, the use of this parameter on some properties, such as PHOTO, LOGO, SOUND, TEL, may not make sense. Canadian French would be specified by this parameter by the following: +SUMMARY;LANGUAGE=fr-CA:... +Date and Time +The date and time values for all vCalendar properties are formatted as a string consistent with the ISO 8601 representation for combinations of dates and times. Either the basic or extended format is allowed. The use of UTC, rather than local time, should be used when ever possible in order to avoid time zone ambiguities. The format for the complete, basic representation of a date and time value is written in the following sequence of characters: +T +For example, 8:30 AM on April 15, 1996 local time would be written as: +19960415T083000 +And the same time in UTC based time would be written as: +19960415T083000Z +Where a value needs to specify a sequence of date and time values, then the property value is a string made up of a list of date and time values, separated by the field separator. For example: +19960101T090000Z; 19960201T090000Z; 19960301T090000Z; 19960401T090000Z; ... +Time Duration +The values for time duration or periods of time for all vCalendar properties are formatted as a string conformant with the ISO 8601 basic representation for duration of time. A given duration of a period of time is represented by a character string consisting of the designator "P", optionally including the number of years followed by the designator "Y", optionally including the number of months followed by the designator "M", optionally including the number of weeks followed by the designator "W", optionally including the number of days followed by the designator "D". The sequence can also contain a time component preceded by the designator "T", optionally including the number of hours followed by the designator "H", optionally including the number of minutes followed by the designator "M", optionally including the number of seconds followed by the designator "S". For example: +P6W +A period of six weeks; +PT15M +A period of 15 minutes; +PT1H30M +A period of 1 hour and thirty minutes; or +P2Y10M15DT10H30M20S +A period of 2 years, 10 months, 15 days, 10 hours, 30 minutes, and 20 seconds. +Value Location +The default location of the property values is inline with the property. However, for some properties, such as those that specify multimedia values, it is efficient to organize the property value as a separate entity (e.g., a file out on the network). The property parameter "VALUE" can be specified to override the "INLINE" location of the property value. In the case of the vCalendar being transported within a MIME email message, the property value can be specified as being located in a separate MIME entity with the "CONTENT-ID" value; or "CID" for shorthand. In this case, the property value is the Content-ID for the MIME entity containing the property value. In addition, the property value can be specified as being located out on the network using the "URL" value. In this case, the property value is the Uniform Resource Locator for the Internet resource containing the property value. This property parameter may be used on any property. However, the use of this parameter on some properties may not make sense; for example the Version, Time Zone, Status, Priority, Mail Reminder, etc. properties. The following specifies a value not located inline with the vCalendar but out in the Internet: +ATTACH;VALUE=URL:http://www.abc.com/dir_photos/my_photo.gif + +Binary Values +The vCalendar specification supports inclusion of binary information, such as computer graphic images (e.g., JPEG), digital audio (e.g., WAVE), or video graphic images (e.g., MPEG). The binary information can either be referenced with a Uniform Reference Locator (URL), referenced with a message using a MIME Content-ID of the MIME part that contains the content, or placed inline in the vCalendar as the value of a property. Inline binary information is included as a property value after being character encoded using Base 64 (default) or Quoted-Printable encoding. +Basic Recurrence Rule Grammar +The specification of recurring events can be simplified by the use of a grammar or rule notation. This specification makes use of the Base Recurrence Rule Grammar from the XAPIA's CSA Specification. +A recurrence rule is a string or clear-text encoding of a recurrence specification. A recurrence rule is composed of several components. A rule begins with a frequency which describes the type of repeating event (e.g., daily, weekly, etc.). This is followed by an interval which indicates how often the frequency repeats (i.e., daily, every third day, etc.). This can be followed by optional frequency modifier information and either an end date or a duration. +Below is the form of a typical rule. This example causes events to be generated every other week on Tuesday and Thursday, for 8 occurrences: +W2 TU TH #4 +Where, W is the Frequency, 2 is the Interval, TU and TH are the optional Frequency Modifiers, and #4 is the Duration. +The basic recurrence rule grammar supports six types of repetition. The six types follow the same form with only the frequency name and optional modifier information changing from one type of frequency to the next. +Daily Rule +The daily rule is used for specifying repeating events based on an interval of a day or more. These can range from every day to every 200th day and beyond. The daily rule begins with the letter D followed by an interval (representing days) and an optional duration or end date. +Some examples follow: +Daily for 10 occurrences: + D1 #10 +Daily until 12/24/94: + D1 19941224T000000Z +Every other day - forever: + D2 #0 +Every 10 days, 5 occurrences: + D10 #5 +Weekly Rule +The weekly rule is used for specifying repeating events based on an interval of a week or more. The basic weekly rule has the same form as the daily rule except that the rule begins with a W and can contain an optional list of weekdays the events are generated on. For weekly rules, the interval represents weeks. Some examples follow: +Weekly for 10 occurrences: + W1 #10 +Weekly until 12/24/94: + W1 19941224T000000Z +Every other week - forever: + W2 #0 +Weekly on Tuesday and +Thursday for 5 weeks: + W1 TU TH #5 +Every other week on Monday Wednesday and Friday until 12/24/94: + W2 MO WE FR 19941224T000000Z +Monthly Rule +The monthly rule is used for specifying repeating events base on an interval of a month or more. There are two types of monthly recurrence rules. One for by-position and one for by-day. The by-position rule allows weekdays in the month to be specified in relation to their occurrence in the month. An example would be to specify the third Sunday of the month or the last Friday of the month. An occurrence specifier may be used in monthly by-position rules. The occurrence specifiers control which occurrence of a weekday in a month an event occurs on: +1+, 2+, ... 5+ for the first occurrence, second, ...fifth occurrence of the month. +1-, 2-, ... 5- for the last occurrence, second to last occurrence, etc. +A 2+ FR SA would indicate the second occurrence of Friday and Saturday in the month. A 1- MO would indicate the first occurrence of Monday working from the end of the month backwards (i.e., the last occurrence). A 2- MO would be the second to the last Monday of the month. +A by-day rule allows actual day numbers to be specified such as the 12th day or 29th day. +The by-position rule begins with a MP and the by-day rule begins with a MD. The interval in monthly rules represents months. Some examples follow: +Monthly on the 1st Friday for ten occurrences: + MP1 1+ FR #10 +Monthly on the 1st Friday until 12/24/94: + MP1 1+ FR 19941224T000000Z +Every other month on the 1st and last +Sunday of the month for 10 occurrences: + MP2 1+ SU 1- SU #10 +Every six months on the 2nd Monday +thru Friday for 10 occurrences: + MP6 2+ MO TU WE TH FR #10 +Monthly on the second last Monday of the month for 6 months: + MP1 2- MO #6 +Monthly on the third to the last day of the month, forever: + MD1 3- #0 +Monthly on the 2nd and 15th of the month for 10 occurrences: + MD1 2 15 #10 +In the next example LD refers to "LastDay" in a monthly recurrence rule. Monthly on the 1st and last day of the month for 10 occurrences: + MD1 1 LD #10 or MD1 1 1- #10 +Every 18 months on the 10th thru 15th of the month for 10 occurrences: + MD18 10 11 12 13 14 15 #10 +Monthly on the second to the last day for 5 months. So, if the start date is August 1996, the event would repeat on 8/30/96, 9/29/96, 10/30/96, 11/29/96, and 12/30/96: + MD1 2- #5 +Yearly Rule +The yearly rule is used for specifying repeating events based on an interval of a year or more. There are two types of yearly recurrence rules. One for by-month and one for by-day. The by-month rule allows specific months out of the year to be specified. The by-day allows specific days to be specified. In the by-month rule, the day in the month the rule is to occur on is determined from the initial appointment. +The by-month rule begins with a YM and the by-day rule begins with a YD. The interval in yearly rules represents years. Some examples follow: +Yearly in June and July for 10 occurrences: + YM1 6 7 #10 +Every other year on January, Feb, and March for 10 occurrences: + YM2 1 2 3 #10 +Every 3rd year on the 1st, 100th and 200th day for 10 occurrences: + YD3 1 100 200 #10 +Grammar +{} 0 or more +[] 0 or 1 +start ::= [] | + [] | + [] | + [] | + [] | + [] +digit ::= <0|1|2|3|4|5|6|7|8|9> +digits ::= {} +enddate ::= ISO 8601_date_time value(e.g., 19940712T101530Z) +interval ::= +duration ::= # +lastday ::= LD +plus ::= + +minus ::= - +daynumber ::= <1-31> [|]| +daynumberlist ::= daynumber {} +month ::= <1-12> +monthlist ::= {} +day ::= <1-366> +daylist ::= {} +occurrence ::= <1-5> | <1-5> +occurrencelist ::= {} +weekday ::= +weekdaylist ::= {} +daily ::= D [] +weekly ::= W [] [] +monthlybypos ::= MP [ ] [] +monthlybyday ::= MD [] [] +yearlybymonth ::= YM [] [] +yearlybyday ::= YD [] [] +Glossary +enddate Controls when a repeating event terminates. The enddate is the last time an event can occur. +interval Defines the frequency in which a rule repeats. +duration Controls the number of events a rule generates. +lastday Can be used as a replacement to daynumber to indicate the last day of the month. +daynumber A number representing a day of the month. +month A number representing a month of the year. +day A number representing a day of the year. +occurrence Controls which week of the month a particular weekday event occurs. +weekday A symbol representing a day of the week. +daily Defines a rule that repeats on a daily basis. +weekly Defines a rule that repeats on a weekly basis. +monthlybypos Defines a rule that repeats on a monthly basis on a relative day and week. +monthlybyday Defines a rule that repeats on a monthly basis on an absolute day. +yearlybymonth Defines a rule that repeats on specific months of the year. +yearlybyday Defines a rule that repeats on specific days of the year. +Policies +The duration portion of a rule defines the total number of events the rule generates, including the first event. +Information, not contained in the rule, necessary to determine the next event time and date is derived from the Start Time entry attribute. +If an end date and a duration is specified in the rule, the recurring event ceases when the end date is reached or the number of events indicated in the duration occur; whichever comes first. +If the duration or an end date is not established in the rule (e.g., D4) the event occurs twice. That is D4 is equivalent to D4 #2. +A duration of #0 means repeat this event forever. +Using the occurrence specifier 5+ (e.g. 5th Friday) or 5- (e.g. 5th from last Friday) in a month that does not contain 5 weeks does not generate an event and thus does not count against the duration. The same applies to providing a day of the month that does not occur in the month. For example the 30th or 31st . +The start time and date of an entry must be synchronized with one of the repeating events defined by its recurrence rule. The following is not allowed: + + Initial Appt Date: 7/1/94 (Friday) + Recurrence Rule: W1 MO TH #5 + +The following is acceptable: + + Initial Appt Date: 7/1/94 (Friday) + Recurrence Rule: W1 MO FR #5 or W1 #5 +If the optional and information is missing from a occurrence the information is derived from the entry attributes. The used in the recurring event is a count from the beginning of the month to the entry date and the used is the day of the week the entry is scheduled to occur on. + +If the occurrence or occurrence does not list a week day (e.g., SU or day 10) in the rule, the week day is established from the entry attribute information. As an example the rule MP1 #3 used in an entry with a start date of 7/20/94 (which is the third Wednesday of the month) repeats on 8/17/94 which is the third Wednesday of the month. +vCalendar Properties +The following properties must appear after the BEGIN:VCALENDAR delimiter but before the occurrence of the BEGIN:VEVENT or BEGIN:VTODO delimiters. These properties apply to the vCalendar object as a whole; unless overridden by a property within the scope of an event or todo entity. +Daylight Savings Rule +This property is identified by the property name DAYLIGHT. This property defines the daylight savings time rule observed by the "home" calendar system that created the vCalendar entity. +Many locations adjust their standard time forward or backward by one hour, in order to accommodate seasonal changes in number of daylight hours. Standard time is also known as Winter Time. Daylight savings time is also known as Advanced Time, Summer Time, or Legal Time in certain countries. +The property value consists of a sequence of components that define the daylight savings time rule. The value consists of the daylight savings time flag, followed by the daylight savings time offset, followed by the date and time that the daylight savings time begins, followed by the date and time that the daylight savings time ends, followed by the standard time designation, followed by the daylight savings time designation. The daylight savings time flag is TRUE if daylight savings time is observed, otherwise it is FALSE and no other components are specified. The daylight savings time offset value is specified in a manner consistent with ISO 8601. The property value is a signed numeric indicating the number of hours and possibly minutes from UTC. The date and time that the daylight savings time begins and ends is specified in a manner consistent with ISO 8601 date and time format. The standard time and daylight savings time designations correspond to the customary character designations. +The following are examples of this property: +DAYLIGHT:TRUE;-06;19960407T025959;19961027T010000;EST;EDT +DAYLIGHT:FALSE +DAYLIGHT:TRUE;-09;19960407T115959;19961027T100000;PST;PDT +Support for this property is optional for implementations conforming to this specification. +Geographic Position +This property is identified by the property name GEO. This property specifies information related to the global position of the "home"system that created the vCalendar object. The property value specifies longitude and latitude. The longitude represents the location east and west of the prime meridian as a positive or negative real number, respectively. The latitude represents the location north and south of the equator as a positive or negative real number, respectively. The following is an example of this property: +GEO:37.24,-17.87 +Support for this property is optional for implementations conforming to this specification. +Product Identifier +This property is identified by the property name PRODID. This property specifies the identifier for the product that created the vCalendar object. The vendor of the implementation should assure that this is a globally unique identifier; using some technique such as an ISO 9070 FPI value. The following is an example of this property: +PRODID:-//ABC Corporation//NONSGML My Product//EN +Support for this property is optional for implementations conforming to this specification. +Time Zone +This property is identified by the property name TZ. This property specifies the standard time zone of the "home" system that created the vCalendar object. The property value is specified in a manner consistent with ISO 8601. The property value is a signed numeric indicating the number of hours and possibly minutes from UTC. Time zones east of UTC are positive numbers. Time zones west of UTC are negative numbers. The following are examples of this property: +TZ:-05 +TZ:+05:30 +Support for this property is optional for implementations conforming to this specification. +Version +This property specifies the identifier corresponding to the highest version number of the vCalendar Specification supported by the implementation that created the vCalendar object. The value of this property must be 1.0 to correspond to this specification.. +This property is identified by the property name VERSION. The following is an example of this property: +VERSION:1.0 +Support for this property is mandatory for implementations conforming to this specification. This property must appear within the vCalendar data stream. +vEvent and vTodo Properties +The following properties may appear within an event or todo calendaring and scheduling entity. +Attachment +This property is identified by the property name ATTACH. The property defines an attached object to the vCalendar entity. For example, a document to be reviewed at a scheduled event or the process steps for a todo. The property value can be a text string, a reference to another message body part or a reference to a URL based document. +Multiple attachments may be specified by including multiple ATTACH properties within the vCalendar entity. +The following are examples of this property: +ATTACH;VALUE=CONTENT-ID: +ATTACH;VALUE=URL:file://xyzCorp.com/pub/reports/r-960812.ps +Support for this property is optional for implementations conforming to this specification. +Attendee +This property is identified by the property name ATTENDEE. The property defines an attendee to a group event or todo. The default property value is an (RFC 822) address. The property may include property parameters ROLE, for the role of the attendee in the event or todo; STATUS, for the status of the attendee's participation in the event or todo, RSVP, for indicating whether the favor of a reply is requested, and EXPECT, to indicate the expectation of the attendee's participation by the originator. +Multiple attendees may be specified by including multiple ATTENDEE properties within the vCalendar entity. +The property value may reference a vCard object. This provides a useful mechanism to allow more than just the address of the attendee to be referenced. +The ROLE property parameter for each attendee can have the following values: + +Description +Property Value + +Indicates an attendee at the event or todo +ATTENDEE + +Indicates organizer of the event, but not owner +ORGANIZER + +Indicates owner of the event or todo. +OWNER + +Indicates a delegate of another attendee. +DELEGATE + + +The default value for this property parameter is ATTENDEE. +The STATUS property parameter for each attendee can have the following values: + +Description +Property Value + +Indicates todo was accepted by attendee +ACCEPTED + +Indicates event or todo requires action by attendee +NEEDS ACTION + +Indicates event or todo was sent out to attendee +SENT + +Indicates event is tentatively accepted by attendee +TENTATIVE + +Indicates attendee has confirmed their attendance at the event +CONFIRMED + +Indicates event or todo has been rejected by attendee +DECLINED + +Indicates todo has been completed by attendee +COMPLETED + +Indicates event or todo has been delegated by the attendee to another +DELEGATED + + +The default value for this property parameter is NEEDS ACTION. +The RSVP property parameter for each attendee can have the following values: + +Description +Property Value + +Indicates a reply is requested +YES + +Indicates a reply is not requested. +NO + + +The default value for this property parameter is NO. +The EXPECT property parameter for each attendee can have the following values: + +Description +Property Value + +Indicates request is for your information. +FYI + +Indicates presence is definitely required. +REQUIRE + +Indicates presence is being requested +REQUEST + +Indicates an immediate response needed. +IMMEDIATE + + +The default value for this property parameter is FYI. +The following is an example of this propertyís use for a todo: +ATTENDEE;ROLE=OWNER;STATUS=COMPLETED:jsmith@host1.com +The following is an example of this property used for specifying multiple attendees to an event: +ATTENDEE;ROLE=OWNER;STATUS=CONFIRMED:John Smith +ATTENDEE;ROLE=ATTENDEE;STATUS=TENTATIVE:Henry Cabot +ATTENDEE;ROLE=DELEGATE;STATUS=CONFIRMED:Jane Doe +The following is an example of this property with the value specified as an URL reference to a vCard that contains the information about the attendee: +ATTENDEE;ROLE=ATTENDEE;STATUS=CONFIRMED;VALUE=URL;TYPE=VCARD: + http://www.xyz.com/~myvcard.vcf +Support for this property is optional for implementations conforming to this specification. +Audio Reminder +This property is identified by the property name AALARM. The property defines an audio reminder for the vCalendar entity. An audio reminder is an alarm that is sounded for the event. +The value for the audio reminder consists of the Run Time, or the date and time that the reminder is to be executed; Snooze Time, or the duration of time after the Run Time that the reminder is to be dormant prior to being repeated; Repeat Count, or the number of times that the reminder is to be repeated; and the Audio Content, or the digital sound to be played when the reminder is executed. +The following are some examples of this property: +AALARM;TYPE=WAVE;VALUE=URL:19960415T235959; ; ; file:///mmedia/taps.wav +AALARM;TYPE=WAVE;VALUE=CONTENT-ID:19960903T060000;PT15M;4; +The property has the following additional property parameters: + +Description +Property Parameter Values + +TYPE + + +Indicates the MIME basic audio content type. +PCM + +Indicates the WAVE format for audio content. +WAVE + +Indicates the AIFF format for audio content. +AIFF + + +The Reminder properties are primarily provided as a means for allowing the capture of alarm information when accessing a calendar system. It may not be an appropriate property to send in an event or todo request. +Support for this property is optional for implementations conforming to this specification. +Categories +This property is identified by the property name CATEGORIES. This property defines the categories for the vCalendar entity. More than one category may be specified as a list of categories separated by the Semi-Colon character (ASCII decimal 59). +The following are some examples of this property: +CATEGORIES:APPOINTMENT;EDUCATION +CATEGORIES:MEETING +Some of the possible values for this property might include the following: + +Some Possible +Property Values + +APPOINTMENT + +BUSINESS + +EDUCATION + +HOLIDAY + +MEETING + +MISCELLANEOUS + +PERSONAL + +PHONE CALL + +SICK DAY + +SPECIAL OCCASION + +TRAVEL + +VACATION + + +Support for this property is mandatory for implementations conforming to this specification. +Classification +This property is identified by the property name CLASS. This property defines the access classification for the vCalendar entity. +A calendar entity access classification is only one component of the general security system within a calendar application. It provides a method of capturing the scope of the access the calendar owner intends for information within an individual calendar entry. The access classification of an individual vCalendar entity is useful when measured along with the other security components of a calendar system (e.g., user authorization, access rights, access role, etc.). Hence, the semantics of the individual access classifications can not be completely defined by this specification. Additionally, due to the "blind" nature of most exchange processes using this specification, these entity classifications can not serve as an enforcement statement for a system receiving a vCalendar data stream. Rather, they provide a method for capturing the intention of the calendar owner for the access to the calendar entry. +The following is an example of this property: +CLASS:PUBLIC +The property can have the following values: + +Description +Property Value + +Indicates general, public access. +PUBLIC + +Indicates restricted, private access. +PRIVATE + +Indicates very restricted, confidential access. +CONFIDENTIAL + + +The default value for this property is PUBLIC. +Support for this property is optional for implementations conforming to this specification. +Date/Time Created +This property is identified by the property name DCREATED. This property specifies the date and time that the vCalendar entity was created within the originating calendar system. This is not generally the same date and time that the vCalendar object was created. The date and time value is the local or UTC based time expressed in the complete representation, basic format as specified in ISO 8601. The following is example of this property: +DCREATED:19960329T083000 +Support for this property is optional for implementations conforming to this specification. +Date/Time Completed +This property is identified by the property name COMPLETED. This property defines the date and time that the todo was actually completed. The date and time value is expressed in the complete representation, basic format as specified in ISO 8601. The time can either be in local or UTC based time. The following is an example of this property: +COMPLETED:19960401T235959 +Support for this property is mandatory for implementations conforming to this specification. +Description +This property is identified by the property name DESCRIPTION. This property provides a more complete description of the vCalendar entity, than that provided by the SUMMARY property. The following is an examples of the property with formatted line breaks in the property value: +DESCRIPTION;ENCODING=QUOTED-PRINTABLE:Meeting to provide technical= + review for "Phoenix" design. =0D=0A= + Happy Face Conference Room. Phoenix design team= + must attend this meeting. RSVP to team leader. +The following is an examples of the property with folding of long lines: +DESCRIPTION:Last draft of the new novel is to be completed + for the editor's proof today. +Support for this property is mandatory for implementations conforming to this specification. +Display Reminder +This property is identified by the property name DALARM. The property defines a display reminder for the vCalendar entity. A display reminder is an alarm that is popped up into the user interface or otherwise visually displayed for the event. +The value for the display reminder consists of the Run Time, or the date and time that the reminder is to be executed; Snooze Time, or the duration of time after the Run Time that the reminder is to be dormant prior to being repeated; Repeat Count, or the number of times that the reminder is to be repeated; and the Display String, or the text to be displayed when the reminder is executed. +The following is an example of this property: +DALARM:19960415T235000;PT5M;2;Your Taxes Are Due !!! +The Reminder properties are primarily provided as a means for allowing the capture of alarm information when accessing a calendar system. It may not be an appropriate property to send in an event or todo request. +Support for this property is optional for implementations conforming to this specification. +Due Date/Time +This property is identified by the property name DUE. This property defines the date and time that the todo is due to be completed. The date and time value is expressed in the complete representation, basic format as specified in ISO 8601. The time can either be in local or UTC based time. The following is an example of this property: +DUE:19960401T235959Z +Support for this property is mandatory for implementations conforming to this specification. +End Date/Time +This property is identified by the property name DTEND. This property defines the date and time that the event will end. The date and time value is expressed in the complete representation, basic format as specified in ISO 8601. The time can either be in local or UTC based time. Events may have an end date/time but no start date/time. In that case, the event does not take up any time. The following is an example of this property: +DTEND:19960401T235959Z +Support for this property is mandatory for implementations conforming to this specification. +Exception Date/Times +This property is identified by the property name EXDATE. This property defines the list of date/time exceptions for a recurring vCalendar entity. The date and time values is expressed in the complete representation, basic format as specified in ISO 8601. The times can either be in local or UTC based time. The number of date/time exceptions is specified by the Number Exceptions property. The following is an exampCONFIRMED;VALUE=URL;TYPE=VCARD: + http://www.xyz.com/~myvcard.vcf +Support for this property is optional for implementations conforming to this specification. +Audio Reminder +This property is identified by the property name AALARM. The property defines an audio reminder for the vCalendar entity. An audio reminder is an alarm that is sounded for the event. +The value for the audio reminder consists of the Run Time, or the date and time that the reminder is to be executed; Snooze Time, or the duration of time after the Run Time that the reminder is to be dormant prior to being repeated; Repeat Count, or the number of times that the reminder is to be repeated; and the Audio Content, or the digital sound to be played when the reminder is executed. +The following are some examples of this property: +AALARM;TYPE=WAVE;VALUE=URL:19960415T235959; ; ; file:///mmedia/taps.wav +AALARM;TYPE=WAVE;VALUE=CONTENT-ID:19960903T060000;PT15M;4; +The property has the following additional property parameters: + +Description +Property Parameter Values + +TYPE + + +Indicates the MIME basic audio content type. +PCM + +Indicates the WAVE format for audio content. +WAVE + +Indicates the AIFF format for audio content. +AIFF + + +The Reminder properties are primarily provided as a means for allowing the capture of alarm information when accessing a calendar system. It may not be an appropriate property to send in an event or todo request. +Support for this property is optional for implementations conforming to this specification. +Categories +This property is identified by the property name CATEGORIES. This property defines the categories for the vCalendar entity. More than one category may be specified as a list of categories separated by the Semi-Colon character (ASCII decimal 59). +The following are some examples of this property: +CATEGORIES:APPOINTMENT;EDUCATION +CATEGORIES:MEETING +Some of the possible values for this property might include the following: + +Some Possible +Property Values + +APPOINTMENT + +BUSINESS + +EDUCATION + +HOLIDAY + +MEETING + +MISCELLANEOUS + +PERSONAL + +PHONE CALL + +SICK DAY + +SPECIAL OCCASION + +TRAVEL + +VACATION + + +Support for this property is mandatory for implementations conforming to this specification. +Classification +This property is identified by the property name CLASS. This property defines the access classification for the vCalendar entity. +A calendar entity access classification is only one component of the general security system within a calendar application. It provides a method of capturing the scope of the access the calendar owner intends for information within an individual calendar entry. The access classification of an individual vCalendar entity is useful when measured along with the other security components of a calendar system (e.g., user authorization, access rights, access role, etc.). Hence, the semantics of the individual access classifications can not be completely defined by this specification. Additionally, due to the "blind" nature of most exchange processes using this specification, these entity classifications can not serve as an enforcement statement for a system receiving a vCalendar data stream. Rather, they provide a method for capturing the intention of the calendar owner for the access to the calendar entry. +The following is an example of this property: +CLASS:PUBLIC +The property can have the following values: + +Description +Property Value + +Indicates general, public access. +PUBLIC + +Indicates restricted, private access. +PRIVATE + +Indicates very restricted, confidential access. +CONFIDENTIAL + + +The default value for this property is PUBLIC. +Support for this property is optional for implementations conforming to this specification. +Date/Time Created +This property is identified by the property name DCREATED. This property specifies the date and time that the vCalendar entity was created within the originating calendar system. This is not generally the same date and time that the vCalendar object was crearty is identified by the property name PALARM. The property defines a procedure reminder for the vCalendar entity. A procedure reminder is a procedure, or application executable that will be run as an alarm for the event. +While this property has many useful purposes, implementors should be aware of the security implications of sending a vCalendar data stream containing this property. The security implications are similar to those associated with active messages within electronic mail. +The value for the procedure reminder consists of the Run Time, or the date and time that the reminder is to be executed; Snooze Time, or the duration of time after the Run Time that the reminder is to be dormant prior to being repeated; Repeat Count, or the number of times that the reminder is to be repeated; and the Procedure Name, or the path to the procedure to be run when the reminder is executed. +The following is an example of this property: +PALARM;VALUE=URL:19960415T235000;PT5M;2;file:///myapps/shockme.exe +The Reminder properties are primarily provided as a means for allowing the capture of alarm information when accessing a calendar system. It may not be an appropriate property to send in an event or todo request. +Support for this property is optional for implementations conforming to this specification. +Related To +This property is identified by the property name RELATED-TO. The property is used to represent relationships or references between this vCalendar entity and another. The property value consists of the persistent, globally unique identifier of another vCalendar entity. This value would be represented in a vCalendar data stream by the UID property. +A linked relationship can be specified by a series of entities that each, in turn, refer to their parent entity. A group relationship can be specified by a number of entities that all refer to one common parent entity. +Changes to a calendar entity referenced by this property may impact the related calendar entity. For example, if a group event changes it start or end date or time, then the related, dependent events will need to have their start and end dates changed in a corresponding way. This property is intended only to provide information on the relationship of calendar entities. It is up to the target calendar system to maintain this relationship. +The following is an example of this property: +RELATED-TO: +RELATED-TO:19960401-080045-4000F192713-0052 +Support for this property is optional for implementations conforming to this specification. +Recurrence Date/Times +This property is identified by the property name RDATE. This property defines the list of date/times for a recurring vCalendar entity. The date and time values is expressed in the complete representation, basic format as specified in ISO 8601. The times can either be in local or UTC based time. The number of recurring date/times is specified by the Number Recurrences property. The following is an example of this property: +RDATE:19960402T010000Z;19960403T010000Z;19960404T010000Z +Support for this property is optional for implementations conforming to this specification. +Recurrence Rule +This property is identified by the property name RRULE. This property defines a rule or repeating pattern for a recurring vCalendar entity, based on the Basic Recurrence Rule Grammar of XAPIA's CSA. The value for the property is a pattern specification for the recurrence. The following is an example of this property: +RRULE:W2 TU TH // Every other week, on Tuesday and Thursday +RRULE:D1 #10 // Daily for 10 occurrences +RRULE:YM1 6 7 #8 // Yearly in June and July for 8 occurrences +Support for this property is optional for implementations conforming to this specification. +Resources +This property is identified by the property name RESOURCES. This property defines the equipment or resources needed in the vCalendar event. +Some of the values that the property may have include the following: + +Some Possible +Property Values + +CATERING + +CHAIRS + +COMPUTER PROJECTOR + +EASEL + +OVERHEAD PROJECTOR + +SPEAKER PHONE + +TABLE + +TV + +VCR + +VIDEO PHONE + +VEHICLE + + +The following is an example of this property: +RESOURCES:EASEL;PROJECTOR;VCR +Support for this property is optional for implementations conforming to this specification. +Sequence Number +This property is identified by the property name SEQUENCE. This property defines the instance of the vCalendar entity in a sequence of revisions. When a vCalendar entity is created its sequence number is zero (ASCII decimal 48). It is incremented each time it is revised. The following is an example of this property: +SEQUENCE:1 +Support for this property is optional for implementations conforming to this specification. +Start Date/Time +This property is identified by the property name DTSTART. This property defines the date and time that the event will start. The date and time value is expressed in the complete representation, basic format as specified in ISO 8601. The time can either be in local or UTC based time. Events may have a start date/time but no end date/time. In that case, the event does not take up any time. The following is an example of this property: +DTSTART:19960401T235959 +Support for this property is mandatory for implementations conforming to this specification. +Status +This property is identified by the property name STATUS. This property defines the status associated with the vCalendar entity. This property can be used when the ATTENDEE property is either not supported or not needed. The following is an example of this property: +STATUS:TENTATIVE +The property can have the following values: + +Description +Property Value + +Indicates todo was accepted +ACCEPTED + +Indicates event or todo requires action +NEEDS ACTION + +Indicates event or todo was sent out. +SENT + +Indicates event is tentatively accepted +TENTATIVE + +Indicates event is confirmed +CONFIRMED + +Indicates event or todo has been declined +DECLINED + +Indicates todo has been completed +COMPLETED + +Indicates event or todo has been delegated +DELEGATED + + +The default value for this property is NEEDS ACTION. +Support for this property is mandatory for implementations conforming to this specification. +Summary +This property is identified by the property name SUMMARY. This property defines a short summary or subject of the vCalendar entity. The following is an example of this property: +SUMMARY:Department Party +Support for this property is mandatory for implementations conforming to this specification. +Time Transparency +This property is identified by the property name TRANSP. This property defines whether the event is transparent to free time searches. The value of this property is a number. A value of zero (ASCII decimal 48) guaranttes that the entry will blocks time and will be factored into a free time search. A value of one (ASCII decimal 49) specifies that the entry will not block time and will not be factored into a free time search. Any values greater than "1" will provide implementation specific transparency semantics. Some implementations may treat values greater than one as non-blocking or transparent events. Other implementations may use the numeric value to provide a layering of levels of transparency. The default value is zero (ASCII decimal 48), the event is not transparent and will block free time searches. The following is an example of this property: +TRANSP:0 +Support for this property is optional for implementations conforming to this specification. +Uniform Resource Locator +This property is identified by the property name URL. This property defines a Uniform Resource Locator for an Internet location that can be used to obtain real-time information associated with the vCalendar entity. Valid values for this property are a string conforming to the IETF RFC 1738, Uniform Resource Locators. The following is an example of this property: +URL:http://abc.com/pub/calendars/jsmith/mytime.or3 +Support for this property is optional for implementations conforming to this specification. +Unique Identifier +This property is identified by the property name UID. This property defines a persistent, globally unique identifier associated with the vCalendar entity. Some examples of forms of unique identifiers would include ISO 9070 formal public identifiers (FPI), X.500 distinguished names, machine-generated "random" numbers with a statistically high likelihood of being globally unique and Uniform Resource Locators (URL). If an URL is specified, it is suggested that the URL reference a service which can render an updated version of the vCalendar for the object. The following is an example of this property: +UID:19960401-080045-4000F192713-0052 +This property is an important method for group scheduling applications to match calendar entities with later modification or deletion requests. Calendaring applications that do not generate this property in vCalendar entities may be limiting their interoperability with other group scheduling applications. +Support for this property is optional for implementations conforming to this specification. +Miscellaneous Properties +Extensions +The clear-text encoding provides a "standard mechanism for doing non-standard things". This extension support is provided for implementers to "push the envelope" on the existing version of the specification. Extension properties are specified by property and/or property parameter names that have the initial sub-string of X- (the two character sequence: Capital X character followed by the Dash character). It is recommended that vendors concatenate onto this sentinel an added short sub-string to identify the vendor. This will facilitate readability of the extensions and minimize possible collision of names between different vendors. All vCalendar Readers are expected to be able to interpret the extension properties and property parameters but may ignore them. The following might be the ABC vendor's extension for an audio-clip form of subject property: +X-ABC-MMSUBJ;TYPE=WAV; VALUE=URL: http://load.noise.org/mysubj.wav +At present, there is no registration authority for names of extension properties. +Support for this property is mandatory for implementations conforming to this specification. However, an implementation may not be able to act on the extension property. Conformance only requires that an implementation be able to parse vCalendar data streams with extensions. The implementation need not act on them. +Formal Definition +The following modified Backus-Naur Notation (BNF) is provided to assist developers in building parsers for the clear-text encoding. + +This syntax is written according to the form described in RFC 822, +but it references just this small subset of RFC 822 literals: + CR = ; ( 15, 13.) + LF = ; ( 12, 10.) + CRLF = CR LF + SPACE = ; ( 40, 32.) + HTAB = ; ( 11, 9.) + +All literal property names are valid as upper, lower, or mixed case. + +ws = 1*(SPACE / HTAB) + ; "whitespace," one or more spaces or tabs + +wsls = 1*(SPACE / HTAB / CRLF) + ; whitespace with line separators + +value = 7bit / 8bit / quoted-printable / base64 + ; The value must be in the encoding type specified for the property value. + +7bit = <7bit us-ascii printable chars, excluding CR LF> + +8bit = + +quoted-printable = + +base64 = + ; the end of the text is marked with two CRLF sequences + ; this results in one blank line before the start of the next + ; property + +groups = groups "." word + / word + +word = + +vcal_file = [wsls] vcal [wsls] + +vcal = "BEGIN" [ws] ":" [ws] "VCALENDAR" [ws] 1*CRLF + calprop calentities [ws] *CRLF + "END" [ws] ":" [ws] "VCALENDAR" [ws] 1*CRLF + +calentities = calentities *CRLF calentity + / calentity + +calentity = evententity + / todoentity + +evententity = "BEGIN" [ws] ":" [ws] "EVENT" [ws] 1*CRLF + entprops [ws] *CRLF + "END" [ws] ":" [ws] "EVENT" [ws] 1*CRLF + +todoentity = "BEGIN" [ws] ":" [ws] "TODO" [ws] 1*CRLF + entprops [ws] *CRLF + "END" [ws] ":" [ws] "TODO" [ws] 1*CRLF + +calprops = calprops *CRLF calprop + / calprop + +calprop = "DAYLIGHT" + [params] ":" value CRLF + / "GEO" + [params] ":" value CRLF + / "PRODID" + [params] ":" value CRLF + / "TZ" + [params] ":" value CRLF + / "VERSION" + [params] ":" "1.0" CRLF + ; The VERSION calendar property MUST appear in the vCalendar object. + +entprops = entprops *CRLF entprop + / entprop + +entprop = [ws] simprop + [params] ":" value CRLF + / [ws] "AALARM" + [params] ":" aalarmparts CRLF + / [ws] "CATEGORIES" + [params] ":" 1*catvals CRLF + / [ws] "CLASS" + [params] ":" classvals CRLF + / [ws] "DALARM" + [params] ":" dalarmparts CRLF + / [ws] "EXDATE" + [params] ":" xdatevals CRLF + / [ws] "MALARM" + [params] ":" malarmparts CRLF + / [ws] "PALARM" + [params] ":" palarmparts CRLF + / [ws] "RDATE" + [params] ":" rdatevals CRLF + / [ws] "RESOURCES" + [params] ":" 1*resvals CRLF + / [ws] "STATUS" + [params] ":" statvals CRLF + +simprop = "ATTACH" / "ATTENDEE" / "DCREATED" / "COMPLETED" + / "DESCRIPTION" / "DUE" / "DTEND" / EXRULE / LAST-MODIFIED + / "LOCATION" / "RNUM" / "PRIORITY" / "RELATED-TO" / "RRULE" + / "SEQUENCE" / "DTSTART" / "SUMMARY" / "TRANSP" / "URL" / "UID" + /"X-" word + +aalarmparts = 0*3(strnosemi ";") strnosemi + ; runTime, snoozeTime, repeatCount, audioContent + +catvals = "APPOINTMENT" / "BUSINESS" / "EDUCATION" / "HOLIDAY" / "MEETING" + / "MISCELLANEOUS" / "PERSONAL" / "PHONE CALL" / "SICK DAY" + / "SPECIAL OCCASION" / "TRAVEL" / "VACATION" / "X-" word / value + +classvals = "PUBLIC" / "PRIVATE" / "CONFIDENTIAL" / "X-" word / value + +dalarmparts = 0*3(strnosemi ";") strnosemi + ; runTime, snoozeTime, repeatCount, displayString + +xdatevals = 1*value + ; One or more date/time values + +malarmparts = 0*4(strnosemi ";") strnosemi + ; runTime, snoozeTime, repeatCount, addressString, noteString + +palarmparts = 0*3(strnosemi ";") strnosemi + ; runTime, snoozeTime, repeatCount, procedureName + +rdatevals = 1*value + ; One or more date/time values + +resvals = "CATERING" / "CHAIRS" / "EASEL" / "PROJECTOR" / "VCR" + / "VEHICLE" / "X-" word / value + +statvals = "ACCEPTED" / "NEEDS ACTION" / "SENT" / "TENTATIVE" + / "CONFIRMED" / "DECLINED" / "COMPLETED" / "DELEGATED" + / "X-" word / value + +params = ";" [ws] paramlist + +paramlist = paramlist [ws] ";" [ws] param + / param + +param = "TYPE" [ws] "=" [ws] ptypeval + / ["VALUE" [ws] "=" [ws]] pvalueval + / ["ENCODING" [ws] "=" [ws]] pencodingval + / "CHARSET" [ws] "=" [ws] charsetval + / "LANGUAGE" [ws] "=" [ws] langval + / "ROLE" [ws] "=" [ws] roleval + / "STATUS" [ws] "=" [ws] statuval + / "X-" word [ws] "=" [ws] word + / knowntype + +ptypeval = knowntype / "X-" word + +knowntype = "WAVE" / "PCM" / "VCARD" / "X-" word / value + +pvalueval = "INLINE" / "URL" / "CONTENT-ID" / "CID" / "X-" word + +pencodingval = "7BIT" / "8BIT" / "QUOTED-PRINTABLE" / "BASE64" / "X-" word + +charsetval = + +langval = + +roleval = "ATTENDEE" / "ORGANIZER" / "OWNER" / "X-" word + +statusval = "ACCEPTED" / "NEEDS ACTION" / "SENT" / "TENTATIVE" / "CONFIRMED" + / "DECLINED" / "COMPLETED" / "DELEGATED" / "X-" word + +strnosemi = *(*nonsemi ("\;" / "\" CRLF)) *nonsemi + ; To include a semicolon in this string, it must be escaped + ; with a "\" character. + +nonsemi = + + + +Section 3 : Internet Recommendations +[DS3] 1 +Recommended Practice With SMTP/MIME +The vCalendar information can be transported through SMTP/MIME based electronic mail services. Interoperability of vCalendar information over SMTP/MIME transports can be better assured by following a common set of recommended practices for encapsulation of the vCalendar. +Text/Plain Content Type +Without any change to existing SMTP or MIME compliant user agents, a vCalendar object can be included within Internet email messages. This might be the case for an existing, simple user agent such as a legacy SMTP mail system. While this approach provides for transport of vCalendars over SMTP services, it does not allow for the end user to take advantage of the full capabilities of either the vCalendar or Internet email (i.e., MIME) functionality. +The following demonstrates how a vCalendar can be included as a SMTP message made up of a RFC 822 message. This may be an initial method for incorporating vCalendar objects into SMTP messages. +Date: Thr, 25 Jan 96 0932 EDT +From: john.smith@host.com +Subject: Re: RFC822 vCalendar Example +Sender: john.smith@host.com +To: smartin@host2.com +Message-ID: + +Steve: Thanks for the call earlier today. Let's get together +tomorrow at 8:30 AM EST to discuss your new proposal. Here is +the meeting notice for your PIM. +BEGIN:VCALENDAR +VERSION:1.0 +BEGIN:VEVENT +CATEGORIES:MEETING +STATUS:TENTATIVE +DTSTART:19960401T033000Z +DTEND:19960401T043000Z +SUMMARY:Your Proposal Review +DESCRIPTION:Steve and John to review newest proposal material +CLASS:PRIVATE +END:VEVENT +END:VCALENDAR +The following example demonstrates how a vCalendar can be included as a separate text/plain content portion within current MIME user agents. +Date: Fri, 26 Jan 1996 07:53:00 -0500 +From: smartin@host2.com +Subject: RE: Text/Plain MIME vCalendar Example +To: john.smith@host.com +Mime-Version: 1.0 +Content-Type: multipart/mixed; boundary=vCalendar +Message-ID: + +--vCalendar +Content-Type:text/plain; charset=us-ascii +Content-Transfer-Encoding: 7bit +John: I can't make that meeting at 8:30. How about doing it +over lunch at noon? Here is an action item for the meeting. +--vCalendar +Content-Type:text/plain; charset=us-ascii; name="MARTIN.VCS" + +BEGIN:VCALENDAR +VERSION:1.0 +BEGIN:VTODO +SUMMARY:John to pay for lunch +DUE:19960401T083000Z +STATUS:NEEDS ACTION +END:VTODO +END:VCALENDAR + +--vCalendar- +Text/X-vCalendar Content Type +The vCalendar object can also be passed as a non-standard MIME media type. This would be useful in order to clearly identify the vCalendar object in an electronic mail message body part. A non-standard, vCalendar object should be identified as the MIME type/subtype "text/x-vCalendar". +The following example demonstrates how a vCalendar containing both an event and a todo can be included as a separate text/x-vCalendar content portion within a MIME user agent. +Date: Fri, 26 Jan 1996 07:53:00 -0500 +From: smartin@host2.com +Subject: RE: Text/X-vCalendar MIME vCalendar Example +To: john.smith@host.com +Mime-Version: 1.0 +Content-Type: multipart/mixed; boundary=vCalendar +Message-ID: + +--vCalendar +Content-Type:text/plain; charset=us-ascii +Content-Transfer-Encoding: 7bit +John: I can't make that meeting at 8:30. How about doing it +over lunch at noon? Here is an event for your PIM. I have +also given you an action item for the meeting. +--vCalendar +Content-Type:text/x-vCalendar; charset=us-ascii; name="MARTIN.VCS" + +BEGIN:VCALENDAR +VERSION:1.0 +BEGIN:VEVENT +CATEGORIES:MEETING +STATUS:NEEDS ACTION +DTSTART:19960401T073000Z +DTEND:19960401T083000Z +SUMMARY:Steve's Proposal Review +DESCRIPTION:Steve and John to review newest proposal material +CLASS:PRIVATE +END:VEVENT +BEGIN:VTODO +SUMMARY:John to pay for lunch +DUE:19960401T083000Z +STATUS:NEEDS ACTION +END:VTODO +END:VCALENDAR + +--vCalendar- +Recommended Practice With HTTP/HTML +The vCalendar specification provides a useful format for conveying calendaring and scheduling information between a Web browser and a HTTP server. Homepages can be used as a web-based document for publishing public events. The events can be easily formatted into vCalendar objects for transfer between the server and a requesting browser. The following examples are provided to illustrate possible scenarios where a non-standard "text/x-vCalendar" MIME type/subtype corresponding the vCalendar can be used to transfer calendaring and scheduling information across the World Wide Web. +The following example demonstrates how a vCalendar object can be included in an HTML document or Web page. This may be an initial method for incorporating vCalendar objects into Web pages. This sample assumes that the Web Browser is capable of handling the OBJECT HTML 3.2 element. + + +HTTP/Web vCalendar Example + + +

Special New Events

+

The latest events to be added to the calendar of activities are:

+
+
+ +Your browser does not support OBJECT or the text/x-vCalendar MIME type/subtype. Get the events' data here and manually use it. + +
+
+
+ +
+
+ + +The following table demonstrates a simple HTTP transaction between client and server that retrieves a vCalendar object from the Web Server. The entries under Client and Server are the actual HTTP headers and data that might be exchanged. + +Client +Direction +Server + +GET martin.vcs HTTP/1.0 +User-Agent: MyBrowser/1.0 +Accept: text/html, text/plain, image/gif, image/jpeg, */* +-> + + + +<- +200 OK +Server: YourServer/1.1 +Date: 25 Jan 96 0932 EDT +Content-Type: text/x-vCalendar +Content-Length: 257 + +BEGIN:VCALENDAR +BEGIN:VEVENT +CATEGORIES:MEETING +STATUS:TENTATIVE +DTSTART:19960401T033000Z +DTEND:19960401T043000Z +SUBJECT:Your Proposal Review +DESCRIPTION:Steve and John to review newest proposal material +CLASS:PRIVATE +END:VEVENT +END:VCALENDAR + + +The following example illustrates how a ìmonth at a glanceî type of information can be displayed on a homepage with the events or todos being links to vCalendar objects. + + +HTTP/Web vCalendar Example + +

Calendar/Events for August

+
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+

Monday

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+ + + +Section 4 : UI Support Recommendations +[DS4] +When integrating vCalendar support into an application, an implementor needs to consider a number of user interface (UI) implications. Most applications provide some levels of support for interacting with other applications. This is usually accomplished in three ways. These include the File System, Clipboard, and Drag/Drop. The full potential of the vCalendar technology can be better utilized if an application supports the vCalendar in each of these UI actions. +File System +It is recommended that applications integrating support for vCalendar specification provide support for importing and exporting vCalendar objects from the operating system's file system. In operating systems that support file types, it is recommended that a file type of VCS be used to distinguish the vCalendar objects. Applications should make use of the file system capabilities to support the FileOpen and FileSaveAs, or their equivalent function, of a vCalendar object. +Clipboard +It is recommended that applications integrating support for the vCalendar specification provide UI capabilities for exchanging vCalendar objects through the operating system's clipboard. In operating systems that provide support for registering clipboard format types, it is recommended that the vCalendar object be registered using the string +//ISBN 1-887687-00-9::versit::PDI//vCalendar. This string is an ISO 9070 Formal Public Identifier (FPI). Applications should make use of the operating system's clipboard capability to support the Cut, Copy, and Paste, or their equivalent function, of a vCalendar object. Applications copying a vCalendar to the clipboard should put the vCalendar object on to the clipboard in both the vCalendar registered format and a plain text format. +Drag/Drop +It is recommended that applications integrating support for the vCalendar specification provide UI capabilities for exchanging vCalendar objects through the operating system's drag/drop capability. In operating systems that provide support for registering drag/drop object types, it is recommended that the vCalendar object be registered using the string +//ISBN 1-887687-00-9::versit::PDI//vCalendar. This string is an ISO 9070 Formal Public Identifier (FPI). Applications should make use of the operating system's drag/drop capability to enable the application to act as either a Drag Source and Drag Target, or their equivalent function, of a vCalendar object. Applications acting as a Drag Source should advertise their ability to render the vCalendar in both the vCalendar registered format and a plain text format. +Where an operating system environment provided multiple drag/drop protocols (e.g., file specification or clipboard based), it is recommended that an implementation provide negotiated support for both. For example, the file specification based drag/drop protocol is useful when dragging a desktop file object or a web based URL to a target application. In addition, the clipboard based drag/drop protocol is useful when dragging an event or todo from a source within an application to a target in another application. Supporting just one of these mechanisms will unnecessarily lead to a lack of interoperability between applications supporting this specifications. +Section 5 : Conformance +[DS5] +In order for a vCalendar Reader or Writer to conform to this specification it must meet the following criteria: +All properties must be implemented as defined. Statements elsewhere in the specification which describe features as optional or with exceptions take precedence over this criterion. +Character set support is up to the underlying implementation. However, support for the default character set (i.e., US ASCII) is required. Optionally, other character sets may be supported. +All extensions are optional. It is requested that any vendor-specific extensions include the vendor identification sub-string in the extension name. For example, the extension name X-ABC- for an extension created by the ABC organization. +All vendor defined extensions must declare the minimum conformance for that extension. + +Section 6 : Extended Recurrence Grammar +[DS6] + +The material in this section is included in this specification for reference information.It is copied, with permission of the XAPIA, from the XAPIA Calendaring and Sceduling API (CSA) Specification. This section defines an extended recurrence rule grammar that may be useful to implementations wishing to extend the capability of the basic recurrence rule defined by this specification. The material is equally applicable to extended support of the exception rules for repeating events. +Rule Introduction +A recurrence rule is made up of one or more recurrence frequencies. The frequencies express the granularity of the repeating event. The smallest granularity is based on minutes, the largest is based on years. Each frequency is immediately followed by an interval. The interval helps to define how often the frequency repeats (daily, every third day, etc): +D2 +Where, where D is the Frequency and 2 is the Interval. +M5 Repeat every five minutes +D1 Repeat daily +D2 Repeat every other day +D3 Repeat every third day +W1 Repeat weekly +W2 Repeat every other week +W3 Repeat every third week +The meaning of the interval depends on the frequency. As an example, the 5 in M5 is in minutes while the 3 in D3 is in days. +A rule can end with the duration symbol, #, followed by a number. This defines the number of times the repetition occurs (including the first time). +D2 #5 +Where, #5 is the Duration. In this example, the event occurs every other day and the duration indicates it occur 5 times. +There may be other information between the frequency and the duration that supplements the meaning of the rule: +D2 1200 1600 #5 +In this example, the event occurs every other day at 1200 and 1600 for a total of 10 occurrences. The duration controls the number of times the rule occurs. In this case the rule defines two occurrences (1200 and 1600) so a total of 10 (2 x 5) occurrences are generated. +A rule can be made up of several recurrence rules: +MP6 1+ MO #5 D2 1200 1600 #5 M5 #3 +This recurrence rule is made up of three recurrence rules. Every time the first rule executes (every 6 months) it executes the next rule to the right. If there is not a rule to the right an event is generated. In this case there is a daily frequency rule to the right of the monthly frequency rule. It executes twice a day; starting on the first Monday of the month. The daily frequency rule executes a total of ten times. Since there is a rule following the daily rule it executes it each time the daily frequency rule executes. The minute frequency rule is executed three times, every time the daily frequency rule executes, for a total of six times a day. The ROWSPAN="2" WIDTH="17%">19: +20: +21: +

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+ + + +Section 4 : UI Support Recommendations +[DS4] +When integrating vCalendar support into an application, an implementor needs to consider a number of user interface (UI) implications. Most applications provide some levels of support for interacting with other applications. This is usually accomplished in three ways. These include the File System, Clipboard, and Drag/Drop. The full potential of the vCalendar technology can be better utilized if an application supports the vCalendar in each of these UI actions. +File System +It is recommended that applications integrating support for vCalendar specification provide support for importing and exporting vCalendar objects from the operating system's file system. In operating systems that support file types, it is recommended that a file type of VCS be used to distinguish the vCalendar objects. Applications should make use of the file system capabilities to support the FileOpen and FileSaveAs, or their equivalent function, of a vCalendar object. +Clipboard +It is recommended that applications integrating support for the vCalendar specification provide UI capabilities for exchanging vCalendar objects through the operating system's clipboard. In operating systems that provide support for registering clipboard format types, it is recommended that the vCalendar object be registered using the string +//ISBN 1-887687-00-9::versit::PDI//vCalendar. This string is an ISO 9070 Formal Public Identifier (FPI). Applications should make use of the operating system's clipboard capability to support the Cut, Copy, and Paste, or their equivalent function, of a vCalendar object. Applications copying a vCalendar to the clipboard should put the vCalendar object on to the clipboard in both the vCalendar registered format and a plain text format. +Drag/Drop +It is recommended that applications integrating support for the vCalendar specification provide UI capabilities for exchanging vCalendar objects through the operating system's drag/drop capability. In operating systems that provide support for registering drag/drop object types, it is recommended that the vCalendar object be registered using the string +//ISBN 1-887687-00-9::versit::PDI//vCalendar. This string is an ISO 9070 Formal Public Identifier (FPI). Applications should make use of the operating system's drag/drop capability to enable the application to act as either a Drag Source and Drag Target, or their equivalent function, of a vCalendar object. Applications acting as a Drag Source should advertise their ability to render the vCalendar in both the vCalendar registered format and a plain text format. +Where an operating system environment provided multiple drag/drop protocols (e.g., file specification or clipboard based), it is recommend days of the year. +Policies +The duration portion of a rule defines the total number of occurrences the rule generates, including the first event. As an example, the rule MP1 #3 W1 #3 starting on 1/1/94 would generate occurrences on 1/1/94, 1/8, 1/15, 2/5/94, 2/12, 2/19, 3/5/94, 3/12, 3/19. +The duration granularity is defined by the recurrence frequency immediately preceding the duration portion of the rule. For example, D1 #5 M15 #4 establishes a repeating event which happens for five days, four times per day. +Information, not contained in the rule, necessary to determine the next event time and date is derived from the event start time. +If no specific time is indicated in the recurrence rule it is taken from the event. +If an end date and a duration for the first rule in a nested rule are specified in the rule, then the recurring event ceases when the end date is reached or the number of occurrences indicated in the duration occur; whichever comes first. +If the duration or and end date is not established in the rule (e.g. ``D2'') the event occurs twice. That is D2 is equivalent to D2 #2. +If an endmark is used in a second or later rule of a nested rule, then the endmark is applied each time that rule is executed by the previous rule. YM1 1 6 #1 MD1 7$ 14 generates occurrences on 1/7 1/14 2/7 6/7 6/14 7/7. +If an endmark is used on a day of the week which is followed by several times (TU$ 1200 1300) or an endmark is used on a week occurrence that is followed by several weekdays (1+$ TU WE) the repeating event stops after the last time or week day in the list is executed. +If a rule has an ambiguity with respect to whether it will repeat on a specific day (12th of the month) vs on a relative day (2nd Friday of the month), the specific day takes precedence. The only exception to this policy is policy 14. +A duration of #0 means repeat this event forever. +Nested rules can not have a duration of 0. These are not allowed: + + YM1 6 #10 MP1 1+ SA #0 + D5 0600 0800 #5 M5 #0 +Using the occurrence specifier 5+ (e.g. 5th Friday) or 5- (e.g. 5th from last Friday) in a month that does not contain 5 weeks does not generate an event and thus does not count against the duration. The same applies to providing a day of the month that does not occur in the month: 31st. +The start time and date of an event must be in-sync with one of the event slots defined by its ocurrence rule. The following are not allowed: + + Initial Appt Time: 1300 + Recurrence Rule: D1 1400 #5 + Initial Appt Date: 7/1/94 (Friday) + Recurrence Rule: W1 MO TH #5 + +The following are acceptable: + + Initial Appt Time: 1300 + Recurrence Rule: D1 #5 or D1 1300 #5 + Initial Appt Date: 7/1/94 (Friday) + Recurrence Rule: W1 MO FR #5 or W1 #5 +If the optional information is missing from a frequency, the information is derived from the initial event. The used in the recurring event is a count from the beginning of the month to the event date and the used is the day of the week the initial event is scheduled to occur on. If the frequency does not list a week day (e.g. SU) in the rule, then the week day is established from the initial event information. As an example, the rule MP1 #3 used in an event with a start date of 7/20/94 (which is the third Wed of the month) will repeat on 8/17/94 which is the third Wed of the month. +The next event of a higher order rule does not execute until all the occurrences of a subrule are generated. If the next event of a higher order rule comes earlier in time than the last event of a subrule then the missed occurrences are not generated. In other words, subrules can not interleave occurrences with other subrules. The following results in indeterminate results because the minute subrule which begins to execute at 0630 generates occurrences beyond 0700 which is when the daily subrule begins executing again: + + D1 0630 0700 #4 M45 #5 + +Another incorrect rule: + + MP1 1+ 1- #3 W2 TU TH #5 + +Examples +Hourly for 12 hours (12:00, 1:00,...10:00, 11:00): +M60 #12 +Every 5 minutes for 1 hour (1:00, 1:05, 1:10,...1:50, 1:55): +M5 #12 +Daily, for 5 days: +D1 #5 +Daily, for 5 days repeating at 10 minute intervals for 1 hour. e.g. 6/1 at 12:00, 12:10, 12:20, ... 12:50; 6/2 at 12:00, 12:10, ... +D1 #5 M10 #6 +Every other day, two times: +D2 +Every other day at 6AM, 12noon and 3PM for a duration of two occurrences (span of three days). e.g. 6/1/94 at 6, 12 and 3PM and 6/3/94 at 6, 12 and 3PM. +D2 0600 1200 1500 #2 +Every other day at 6AM, 12noon and 3PM for a duration of three occurrences (a span of 5 days) stopping at noon on the fifth day. e.g. 6/1/94 at 6, 12, and 3, 6/3/94 at 6, 12 and 3 and 6/5/94 at 6 and 12. +D2 0600 1200$ 1500 #3 +Weekly at 6 AM (repeat every 15 minutes for an hour) for five weeks. e.g. 6:00, 6:15, 6:30, 6:45 on 6/1, 6/8, 6/15, 6/22 and 6/29. +D7 0600 #5 M15 #4 +Weekly at 6 AM (repeat every 15 minutes for an hour) for four weeks stopping at 6AM on the last event day. e.g. 6:00, 6:15, 6:30, 6:45 on 6/1, 6/8, 6/15 and 6:00 on 6/22. +D7 0600$ #4 M15 #4 +Weekly at 6 AM (repeat every 15 minutes for an hour) for 1 week stopping at 6:45AM. e.g. 6:00, 6:15, 6:30, 6:45 on 6/1. +D7 0600 #1 M15 #4 or +D7 #1 M15 #4 /* start time defined in appt entry */ or +M15 #4 /* start time defined in appt entry */ +Weekly for four weeks: +W1 #4 +Biweekly on Monday and Tuesday for 2 occurrences ending on a Monday: +W2 MO$ TU #2 +Weekly on Tuesday and Thursday at the time specified in the appt and repeated at time + 5 minutes: +W1 TU TH #3 M5 #2 +Weekly on Tuesday at 1200 and 1230 and Thursday at 1130 and 1200 for 10 weeks: +W1 TU 1200 TH 1130 #10 M30 or +W1 TU 1200 1230 TH 1130 1200 #10 +Weekly on Tuesday at 1200 and 1230 and Thursday at 1130 and 1200 for 10 weeks stopping on the last TU at 1230: +W1 TU$ 1200 TH 1130 #10 M30 or +W1 TU$ 1200 1230 TH 1130 1200 #10 +Weekly on Tuesday at 1200 and 1230 and Thursday at 1130 and 1200 for 10 weeks stopping on the last Tuesday at 1200: +W1 TU 1200$ 1230 TH 1130 1200 #10 +Monthly for 1 year: +MP1 #12 +Every other month on the first and last Friday of the month for 5 months: +MP2 1+ 1- FR #3 +Monthly on the second to the last day of the month for 5 months: +MD1 2- #5 +Monthly on the second to the last Monday of the month for 6 months: +MP1 2- MO #6 +Monthly on the third to the last day of the month for forever: +MD1 3- #0 +Monthly on the seventh to the last day of the month for 12 months: +MD1 7- #12 +Every other month on the first and last Friday of the month for 5 months stopping on the first Friday in the fifth month: +MP2 1+$ 1- FR #3 +Every six months on the first Monday of the month (repeat for 5 days) for 24 months: +MP6 1+ MO #5 D1 #5 +Every six months on the first Monday of the month (repeat every other day at 0600, 1200 and 1500 for 20 days) for 24 months: +MP6 1+ MO #5 D2 0600 1200 1500 #10 +Every six months on the first Monday of the month (repeat every other day at 0600, 1200 and 1500 for 20 days (repeat every 5 minutes for 3 times)) for 24 months: +MP6 1+ MO #5 D2 0600 1200 1500 #10 M5 #3 +Every six months on the first Monday of the month and the second to last Thursday of the month (repeat five minutes later) for 24 months: +MP6 1+ MO 2- TH #5 M5 #2 +Every six months on the first SU and MO at Noon, the second TU and WE at 1:00PM and the third TH and FR at 2:00PM: +MP6 1+ SU MO 1200 2+ TU WE 1300 3+ TH FR 1400 #4 +Every month on the 7th for 12 months: +MD1 7 #12 +Every month on the 7th, 14th, 21st, 28th for 12 months +MD1 7 14 21 28 #12 +Every month on the 10th and 20th for 24 months - daily for 5 days at 0600, 1200 and 1600 - every 15 minutes for an hour: +MD1 10 20 #24 D1 0600 1200 1600 #5 M15 #4 +Yearly on the 1st, 6th and 12 month on the first Monday and last Friday of the month: +YM1 1 6 12 #5 MP1 1+ MO 1- FR +Every other year on the 6th month (on the 12th day) for 5 years. +YM2 6 #3 MD1 12 +Yearly on the 7th 14th 21st and 28th of the 1st 3rd and 8th month and on the 7th and 14th of the 2nd, 4th and 9th months ending on the 4th month, 14th day of the 5th year: +YM1 1 3$ 8 #5 MD1 7 14$ 21 28 +Yearly on the 6th, 9th and 10th month on all weekends of the month: +YM1 6 9 10 #10 MP1 1+ 2+ 3+ 4+ 1- SA SU #1 +Yearly on the 6th month for 10 years, weekly on Tuesday and Thursday at 1100 and 1300 for 4 weeks: +YM1 6 #10 W1 TU TH 1100 1300 #4 +Yearly on the 1st, 100th, 200th and 300th day for 4 years: +YD1 1 100 200 300 #4 +Yearly on the 1st - 5th days and 100th - 104th days: +YD1 1 100 #5 D1 #5 +Yearly on the 1st - 5th days and 100th - 104th days stopping on 1/2/99: +YD1 1 100 D1 #5 19990102T000000Z + +[DS1]This entry/line in the section is assigned the style for the level 1 heading. This is done so that a section number can be given in the chapter title (style ìchptr_titleî) and so that ìheading 1î (more specifically, the format/heading numbering of the form ì1. Overviewî) can be ìskipped,î and the appropriate form for the next-level of heading can be properly displayed (eg., "1.1 Overview"). It is, and must be, formatted as "hidden text" prior to pagination and/or printing. +[DS2]This entry/line in the section is assigned the style for the level 1 heading. This is done so that a section number can be given in the chapter title (style ìchptr_titleî) and so that ìheading 1î (more specifically, the format/heading numbering of the form ì1. Overviewî) can be ìskipped,î and the appropriate form for the next-level of heading can be properly displayed (eg., "1.1 Overview"). It is, and must be, formatted as "hidden text" prior to pagination and/or printing. +[DS3]This entry/line in the section is assigned the style for the level 1 heading. This is done so that a section number can be given in the chapter title (style ìchptr_titleî) and so that ìheading 1î (more specifically, the format/heading numbering of the form ì1. Overviewî) can be ìskipped,î and the appropriate form for the next-level of heading can be properly displayed (eg., ì1.1 Overview"). It is, and must be, formatted as "hidden text" prior to pagination and/or printing. +[DS4]This entry/line in the section is assigned the style for the level 1 heading. This is done so that a section number can be given in the chapter title (style ìchptr_titleî) and so that ìheading 1î (more specifically, the format/heading numbering of the form ì1. Overviewî) can be ìskipped,î and the appropriate form for the next-level of heading can be properly displayed (eg., ì1.1 Overview"). It is, and must be, formatted as "hidden text" prior to pagination and/or printing. +[DS5]This entry/line in the section is assigned the style for the level 1 heading. This is done so that a section number can be given in the chapter title (style ìchptr_titleî) and so that ìheading 1î (more specifically, the format/heading numbering of the form ì1. Overviewî) can be ìskipped,î and the appropriate form for the next-level of heading can be properly displayed (eg., ì1.1 Overview"). It is, and must be, formatted as "hidden text" prior to pagination and/or printing. +[DS6]This entry/line in the section is assigned the style for the level 1 heading. This is done so that a section number can be given in the chapter title (style ìchptr_titleî) and so that ìheading 1î (more specifically, the format/heading numbering of the form ì1. Overviewî) can be ìskipped,î and the appropriate form for the next-level of heading can be properly displayed (eg., ì1.1 Overviewî). It is, and must be, formatted as "hidden text" prior to pagination and/or printing. + + + + + + + +Copyrights + + + + + + + +Trademarks +vi vCalendar Specification, v0.4 + +Reference Information v + +versit Update vii + + + + + + + +4 vCalendar Specification, v0.4 + +Contents ix + + + + +Section 1 : Introduction 3 + diff --git a/VisualCard/Specs/vcalendar-20-rfc5545.txt b/VisualCard/Specs/vcalendar-20-rfc5545.txt new file mode 100644 index 0000000..47ea31d --- /dev/null +++ b/VisualCard/Specs/vcalendar-20-rfc5545.txt @@ -0,0 +1,9411 @@ + + + + + + +Network Working Group B. Desruisseaux, Ed. +Request for Comments: 5545 Oracle +Obsoletes: 2445 September 2009 +Category: Standards Track + + + Internet Calendaring and Scheduling Core Object Specification + (iCalendar) + +Abstract + +This document defines the iCalendar data format for representing and +exchanging calendaring and scheduling information such as events, +to-dos, journal entries, and free/busy information, independent of any +particular calendar service or protocol. + +Status of This Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright and License Notice + + Copyright (c) 2009 IETF Trust and the persons identified as the + document authors. All rights reserved. + + This document is subject to BCP 78 and the IETF Trust's Legal + Provisions Relating to IETF Documents + (http://trustee.ietf.org/license-info) in effect on the date of + publication of this document. Please review these documents + carefully, as they describe your rights and restrictions with respect + to this document. Code Components extracted from this document must + include Simplified BSD License text as described in Section 4.e of + the Trust Legal Provisions and are provided without warranty as + described in the BSD License. + + This document may contain material from IETF Documents or IETF + Contributions published or made publicly available before November + 10, 2008. The person(s) controlling the copyright in some of this + material may not have granted the IETF Trust the right to allow + modifications of such material outside the IETF Standards Process. + Without obtaining an adequate license from the person(s) controlling + the copyright in such materials, this document may not be modified + outside the IETF Standards Process, and derivative works of it may + not be created outside the IETF Standards Process, except to format + + + +Desruisseaux Standards Track [Page 1] + +RFC 5545 iCalendar September 2009 + + + it for publication as an RFC or to translate it into languages other + than English. + +Table of Contents + + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 + 2. Basic Grammar and Conventions . . . . . . . . . . . . . . . . 6 + 2.1. Formatting Conventions . . . . . . . . . . . . . . . . . 6 + 2.2. Related Memos . . . . . . . . . . . . . . . . . . . . . . 7 + 3. iCalendar Object Specification . . . . . . . . . . . . . . . 8 + 3.1. Content Lines . . . . . . . . . . . . . . . . . . . . . . 8 + 3.1.1. List and Field Separators . . . . . . . . . . . . . . 11 + 3.1.2. Multiple Values . . . . . . . . . . . . . . . . . . . 11 + 3.1.3. Binary Content . . . . . . . . . . . . . . . . . . . 11 + 3.1.4. Character Set . . . . . . . . . . . . . . . . . . . . 12 + 3.2. Property Parameters . . . . . . . . . . . . . . . . . . . 12 + 3.2.1. Alternate Text Representation . . . . . . . . . . . . 13 + 3.2.2. Common Name . . . . . . . . . . . . . . . . . . . . . 15 + 3.2.3. Calendar User Type . . . . . . . . . . . . . . . . . 15 + 3.2.4. Delegators . . . . . . . . . . . . . . . . . . . . . 16 + 3.2.5. Delegatees . . . . . . . . . . . . . . . . . . . . . 16 + 3.2.6. Directory Entry Reference . . . . . . . . . . . . . . 17 + 3.2.7. Inline Encoding . . . . . . . . . . . . . . . . . . . 17 + 3.2.8. Format Type . . . . . . . . . . . . . . . . . . . . . 18 + 3.2.9. Free/Busy Time Type . . . . . . . . . . . . . . . . . 19 + 3.2.10. Language . . . . . . . . . . . . . . . . . . . . . . 20 + 3.2.11. Group or List Membership . . . . . . . . . . . . . . 20 + 3.2.12. Participation Status . . . . . . . . . . . . . . . . 21 + 3.2.13. Recurrence Identifier Range . . . . . . . . . . . . . 22 + 3.2.14. Alarm Trigger Relationship . . . . . . . . . . . . . 23 + 3.2.15. Relationship Type . . . . . . . . . . . . . . . . . . 24 + 3.2.16. Participation Role . . . . . . . . . . . . . . . . . 25 + 3.2.17. RSVP Expectation . . . . . . . . . . . . . . . . . . 25 + 3.2.18. Sent By . . . . . . . . . . . . . . . . . . . . . . . 26 + 3.2.19. Time Zone Identifier . . . . . . . . . . . . . . . . 26 + 3.2.20. Value Data Types . . . . . . . . . . . . . . . . . . 28 + 3.3. Property Value Data Types . . . . . . . . . . . . . . . . 29 + 3.3.1. Binary . . . . . . . . . . . . . . . . . . . . . . . 29 + 3.3.2. Boolean . . . . . . . . . . . . . . . . . . . . . . . 30 + 3.3.3. Calendar User Address . . . . . . . . . . . . . . . . 30 + 3.3.4. Date . . . . . . . . . . . . . . . . . . . . . . . . 31 + 3.3.5. Date-Time . . . . . . . . . . . . . . . . . . . . . . 31 + 3.3.6. Duration . . . . . . . . . . . . . . . . . . . . . . 34 + 3.3.7. Float . . . . . . . . . . . . . . . . . . . . . . . . 35 + 3.3.8. Integer . . . . . . . . . . . . . . . . . . . . . . . 35 + 3.3.9. Period of Time . . . . . . . . . . . . . . . . . . . 36 + 3.3.10. Recurrence Rule . . . . . . . . . . . . . . . . . . . 37 + 3.3.11. Text . . . . . . . . . . . . . . . . . . . . . . . . 45 + + + +Desruisseaux Standards Track [Page 2] + +RFC 5545 iCalendar September 2009 + + + 3.3.12. Time . . . . . . . . . . . . . . . . . . . . . . . . 46 + 3.3.13. URI . . . . . . . . . . . . . . . . . . . . . . . . . 48 + 3.3.14. UTC Offset . . . . . . . . . . . . . . . . . . . . . 49 + 3.4. iCalendar Object . . . . . . . . . . . . . . . . . . . . 49 + 3.5. Property . . . . . . . . . . . . . . . . . . . . . . . . 50 + 3.6. Calendar Components . . . . . . . . . . . . . . . . . . . 50 + 3.6.1. Event Component . . . . . . . . . . . . . . . . . . . 52 + 3.6.2. To-Do Component . . . . . . . . . . . . . . . . . . . 56 + 3.6.3. Journal Component . . . . . . . . . . . . . . . . . . 58 + 3.6.4. Free/Busy Component . . . . . . . . . . . . . . . . . 60 + 3.6.5. Time Zone Component . . . . . . . . . . . . . . . . . 63 + 3.6.6. Alarm Component . . . . . . . . . . . . . . . . . . . 72 + 3.7. Calendar Properties . . . . . . . . . . . . . . . . . . . 77 + 3.7.1. Calendar Scale . . . . . . . . . . . . . . . . . . . 77 + 3.7.2. Method . . . . . . . . . . . . . . . . . . . . . . . 78 + 3.7.3. Product Identifier . . . . . . . . . . . . . . . . . 79 + 3.7.4. Version . . . . . . . . . . . . . . . . . . . . . . . 80 + 3.8. Component Properties . . . . . . . . . . . . . . . . . . 81 + 3.8.1. Descriptive Component Properties . . . . . . . . . . 81 + 3.8.1.1. Attachment . . . . . . . . . . . . . . . . . . . 81 + 3.8.1.2. Categories . . . . . . . . . . . . . . . . . . . 82 + 3.8.1.3. Classification . . . . . . . . . . . . . . . . . 83 + 3.8.1.4. Comment . . . . . . . . . . . . . . . . . . . . . 84 + 3.8.1.5. Description . . . . . . . . . . . . . . . . . . . 85 + 3.8.1.6. Geographic Position . . . . . . . . . . . . . . . 87 + 3.8.1.7. Location . . . . . . . . . . . . . . . . . . . . 88 + 3.8.1.8. Percent Complete . . . . . . . . . . . . . . . . 89 + 3.8.1.9. Priority . . . . . . . . . . . . . . . . . . . . 90 + 3.8.1.10. Resources . . . . . . . . . . . . . . . . . . . . 92 + 3.8.1.11. Status . . . . . . . . . . . . . . . . . . . . . 93 + 3.8.1.12. Summary . . . . . . . . . . . . . . . . . . . . . 94 + 3.8.2. Date and Time Component Properties . . . . . . . . . 95 + 3.8.2.1. Date-Time Completed . . . . . . . . . . . . . . . 95 + 3.8.2.2. Date-Time End . . . . . . . . . . . . . . . . . . 96 + 3.8.2.3. Date-Time Due . . . . . . . . . . . . . . . . . . 97 + 3.8.2.4. Date-Time Start . . . . . . . . . . . . . . . . . 99 + 3.8.2.5. Duration . . . . . . . . . . . . . . . . . . . . 100 + 3.8.2.6. Free/Busy Time . . . . . . . . . . . . . . . . . 101 + 3.8.2.7. Time Transparency . . . . . . . . . . . . . . . . 102 + 3.8.3. Time Zone Component Properties . . . . . . . . . . . 103 + 3.8.3.1. Time Zone Identifier . . . . . . . . . . . . . . 103 + 3.8.3.2. Time Zone Name . . . . . . . . . . . . . . . . . 105 + 3.8.3.3. Time Zone Offset From . . . . . . . . . . . . . . 106 + 3.8.3.4. Time Zone Offset To . . . . . . . . . . . . . . . 106 + 3.8.3.5. Time Zone URL . . . . . . . . . . . . . . . . . . 107 + 3.8.4. Relationship Component Properties . . . . . . . . . . 108 + 3.8.4.1. Attendee . . . . . . . . . . . . . . . . . . . . 108 + 3.8.4.2. Contact . . . . . . . . . . . . . . . . . . . . . 111 + + + +Desruisseaux Standards Track [Page 3] + +RFC 5545 iCalendar September 2009 + + + 3.8.4.3. Organizer . . . . . . . . . . . . . . . . . . . . 113 + 3.8.4.4. Recurrence ID . . . . . . . . . . . . . . . . . . 114 + 3.8.4.5. Related To . . . . . . . . . . . . . . . . . . . 117 + 3.8.4.6. Uniform Resource Locator . . . . . . . . . . . . 118 + 3.8.4.7. Unique Identifier . . . . . . . . . . . . . . . . 119 + 3.8.5. Recurrence Component Properties . . . . . . . . . . . 120 + 3.8.5.1. Exception Date-Times . . . . . . . . . . . . . . 120 + 3.8.5.2. Recurrence Date-Times . . . . . . . . . . . . . . 122 + 3.8.5.3. Recurrence Rule . . . . . . . . . . . . . . . . . 124 + 3.8.6. Alarm Component Properties . . . . . . . . . . . . . 134 + 3.8.6.1. Action . . . . . . . . . . . . . . . . . . . . . 134 + 3.8.6.2. Repeat Count . . . . . . . . . . . . . . . . . . 135 + 3.8.6.3. Trigger . . . . . . . . . . . . . . . . . . . . . 135 + 3.8.7. Change Management Component Properties . . . . . . . 138 + 3.8.7.1. Date-Time Created . . . . . . . . . . . . . . . . 138 + 3.8.7.2. Date-Time Stamp . . . . . . . . . . . . . . . . . 139 + 3.8.7.3. Last Modified . . . . . . . . . . . . . . . . . . 140 + 3.8.7.4. Sequence Number . . . . . . . . . . . . . . . . . 141 + 3.8.8. Miscellaneous Component Properties . . . . . . . . . 142 + 3.8.8.1. IANA Properties . . . . . . . . . . . . . . . . . 142 + 3.8.8.2. Non-Standard Properties . . . . . . . . . . . . . 142 + 3.8.8.3. Request Status . . . . . . . . . . . . . . . . . 144 + 4. iCalendar Object Examples . . . . . . . . . . . . . . . . . . 146 + 5. Recommended Practices . . . . . . . . . . . . . . . . . . . . 150 + 6. Internationalization Considerations . . . . . . . . . . . . . 151 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 151 + 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 151 + 8.1. iCalendar Media Type Registration . . . . . . . . . . . . 151 + 8.2. New iCalendar Elements Registration . . . . . . . . . . . 155 + 8.2.1. iCalendar Elements Registration Procedure . . . . . . 155 + 8.2.2. Registration Template for Components . . . . . . . . 155 + 8.2.3. Registration Template for Properties . . . . . . . . 156 + 8.2.4. Registration Template for Parameters . . . . . . . . 156 + 8.2.5. Registration Template for Value Data Types . . . . . 157 + 8.2.6. Registration Template for Values . . . . . . . . . . 157 + 8.3. Initial iCalendar Elements Registries . . . . . . . . . . 158 + 8.3.1. Components Registry . . . . . . . . . . . . . . . . . 158 + 8.3.2. Properties Registry . . . . . . . . . . . . . . . . . 158 + 8.3.3. Parameters Registry . . . . . . . . . . . . . . . . . 161 + 8.3.4. Value Data Types Registry . . . . . . . . . . . . . . 162 + 8.3.5. Calendar User Types Registry . . . . . . . . . . . . 162 + 8.3.6. Free/Busy Time Types Registry . . . . . . . . . . . . 163 + 8.3.7. Participation Statuses Registry . . . . . . . . . . . 163 + 8.3.8. Relationship Types Registry . . . . . . . . . . . . . 164 + 8.3.9. Participation Roles Registry . . . . . . . . . . . . 164 + 8.3.10. Actions Registry . . . . . . . . . . . . . . . . . . 165 + 8.3.11. Classifications Registry . . . . . . . . . . . . . . 165 + 8.3.12. Methods Registry . . . . . . . . . . . . . . . . . . 165 + + + +Desruisseaux Standards Track [Page 4] + +RFC 5545 iCalendar September 2009 + + + 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 165 + 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 166 + 10.1. Normative References . . . . . . . . . . . . . . . . . . 166 + 10.2. Informative References . . . . . . . . . . . . . . . . . 167 + Appendix A. Differences from RFC 2445 . . . . . . . . . . . . . 169 + A.1. New Restrictions . . . . . . . . . . . . . . . . . . . . 169 + A.2. Restrictions Removed . . . . . . . . . . . . . . . . . . 169 + A.3. Deprecated Features . . . . . . . . . . . . . . . . . . . 169 + +1. Introduction + + The use of calendaring and scheduling has grown considerably in the + last decade. Enterprise and inter-enterprise business has become + dependent on rapid scheduling of events and actions using this + information technology. This memo is intended to progress the level + of interoperability possible between dissimilar calendaring and + scheduling applications. This memo defines a MIME content type for + exchanging electronic calendaring and scheduling information. The + Internet Calendaring and Scheduling Core Object Specification, or + iCalendar, allows for the capture and exchange of information + normally stored within a calendaring and scheduling application; such + as a Personal Information Manager (PIM) or a Group-Scheduling + product. + + The iCalendar format is suitable as an exchange format between + applications or systems. The format is defined in terms of a MIME + content type. This will enable the object to be exchanged using + several transports, including but not limited to SMTP, HTTP, a file + system, desktop interactive protocols such as the use of a memory- + based clipboard or drag/drop interactions, point-to-point + asynchronous communication, wired-network transport, or some form of + unwired transport such as infrared. + + The memo also provides for the definition of iCalendar object methods + that will map this content type to a set of messages for supporting + calendaring and scheduling operations such as requesting, replying + to, modifying, and canceling meetings or appointments, to-dos, and + journal entries. The iCalendar object methods can be used to define + other calendaring and scheduling operations such as requesting for + and replying with free/busy time data. Such a scheduling protocol is + defined in the iCalendar Transport-independent Interoperability + Protocol (iTIP) defined in [2446bis]. + + The memo also includes a formal grammar for the content type based on + the Internet ABNF defined in [RFC5234]. This ABNF is required for + the implementation of parsers and to serve as the definitive + reference when ambiguities or questions arise in interpreting the + descriptive prose definition of the memo. Additional restrictions + + + +Desruisseaux Standards Track [Page 5] + +RFC 5545 iCalendar September 2009 + + + that could not easily be expressed with the ABNF syntax are specified + as comments in the ABNF. Comments with normative statements should + be treated as such. + +2. Basic Grammar and Conventions + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in [RFC2119]. + + This memo makes use of both a descriptive prose and a more formal + notation for defining the calendaring and scheduling format. + + The notation used in this memo is the ABNF notation of [RFC5234]. + Readers intending on implementing the format defined in this memo + should be familiar with this notation in order to properly interpret + the specifications of this memo. + + All numeric values used in this memo are given in decimal notation. + + All names of properties, property parameters, enumerated property + values, and property parameter values are case-insensitive. However, + all other property values are case-sensitive, unless otherwise + stated. + + Note: All indented editorial notes, such as this one, are intended + to provide the reader with additional information. The + information is not essential to the building of an implementation + conformant with this memo. The information is provided to + highlight a particular feature or characteristic of the memo. + + The format for the iCalendar object is based on the syntax of the + text/directory media type [RFC2425]. While the iCalendar object is + not a profile of the text/directory media type [RFC2425], it does + reuse a number of the elements from the [RFC2425] specification. + +2.1. Formatting Conventions + + The elements defined in this memo are defined in prose. Many of the + terms used to describe these have common usage that is different than + the standards usage of this memo. In order to reference, within this + memo, elements of the calendaring and scheduling model, core object + (this memo), or interoperability protocol [2446bis] some formatting + conventions have been used. Calendaring and scheduling roles are + referred to in quoted-strings of text with the first character of + each word in uppercase. For example, "Organizer" refers to a role of + a "Calendar User" within the scheduling protocol defined by + [2446bis]. Calendar components defined by this memo are referred to + + + +Desruisseaux Standards Track [Page 6] + +RFC 5545 iCalendar September 2009 + + + with capitalized, quoted-strings of text. All calendar components + start with the letter "V". For example, "VEVENT" refers to the event + calendar component, "VTODO" refers to the to-do calendar component, + and "VJOURNAL" refers to the daily journal calendar component. + Scheduling methods defined by iTIP [2446bis] are referred to with + capitalized, quoted-strings of text. For example, "REQUEST" refers + to the method for requesting a scheduling calendar component be + created or modified, and "REPLY" refers to the method a recipient of + a request uses to update their status with the "Organizer" of the + calendar component. + + The properties defined by this memo are referred to with capitalized, + quoted-strings of text, followed by the word "property". For + example, "ATTENDEE" property refers to the iCalendar property used to + convey the calendar address of a calendar user. Property parameters + defined by this memo are referred to with lowercase, quoted-strings + of text, followed by the word "parameter". For example, "value" + parameter refers to the iCalendar property parameter used to override + the default value type for a property value. Enumerated values + defined by this memo are referred to with capitalized text, either + alone or followed by the word "value". For example, the "MINUTELY" + value can be used with the "FREQ" component of the "RECUR" value type + to specify repeating components based on an interval of one minute or + more. + + The following table lists the different characters from the + [US-ASCII] character set that is referenced in this document. For + each character, the table specifies the character name used + throughout this document, along with its US-ASCII decimal codepoint. + + + + + + + + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 7] + +RFC 5545 iCalendar September 2009 + + + +------------------------+-------------------+ + | Character name | Decimal codepoint | + +------------------------+-------------------+ + | HTAB | 9 | + | LF | 10 | + | CR | 13 | + | DQUOTE | 22 | + | SPACE | 32 | + | PLUS SIGN | 43 | + | COMMA | 44 | + | HYPHEN-MINUS | 45 | + | PERIOD | 46 | + | SOLIDUS | 47 | + | COLON | 58 | + | SEMICOLON | 59 | + | LATIN CAPITAL LETTER N | 78 | + | LATIN CAPITAL LETTER T | 84 | + | LATIN CAPITAL LETTER X | 88 | + | LATIN CAPITAL LETTER Z | 90 | + | BACKSLASH | 92 | + | LATIN SMALL LETTER N | 110 | + +------------------------+-------------------+ + +2.2. Related Memos + + Implementers will need to be familiar with several other memos that, + along with this memo, form a framework for Internet calendaring and + scheduling standards. This memo specifies a core specification of + objects, value types, properties, and property parameters. + + o iTIP [2446bis] specifies an interoperability protocol for + scheduling between different implementations; + + o iCalendar Message-Based Interoperability Protocol (iMIP) [2447bis] + specifies an Internet email binding for [2446bis]. + + This memo does not attempt to repeat the specification of concepts or + definitions from these other memos. Where possible, references are + made to the memo that provides for the specification of these + concepts or definitions. + +3. iCalendar Object Specification + + The following sections define the details of a Calendaring and + Scheduling Core Object Specification. The Calendaring and Scheduling + Core Object is a collection of calendaring and scheduling + information. Typically, this information will consist of an + iCalendar stream with one or more iCalendar objects. The body of the + + + +Desruisseaux Standards Track [Page 8] + +RFC 5545 iCalendar September 2009 + + + iCalendar object consists of a sequence of calendar properties and + one or more calendar components. + + Section 3.1 defines the content line format; Section 3.2 defines the + property parameter format; Section 3.3 defines the data types for + property values; Section 3.4 defines the iCalendar object format; + Section 3.5 defines the iCalendar property format; Section 3.6 + defines the calendar component format; Section 3.7 defines calendar + properties; and Section 3.8 defines calendar component properties. + + This information is intended to be an integral part of the MIME + content type registration. In addition, this information can be used + independent of such content registration. In particular, this memo + has direct applicability for use as a calendaring and scheduling + exchange format in file-, memory-, or network-based transport + mechanisms. + +3.1. Content Lines + + The iCalendar object is organized into individual lines of text, + called content lines. Content lines are delimited by a line break, + which is a CRLF sequence (CR character followed by LF character). + + Lines of text SHOULD NOT be longer than 75 octets, excluding the line + break. Long content lines SHOULD be split into a multiple line + representations using a line "folding" technique. That is, a long + line can be split between any two characters by inserting a CRLF + immediately followed by a single linear white-space character (i.e., + SPACE or HTAB). Any sequence of CRLF followed immediately by a + single linear white-space character is ignored (i.e., removed) when + processing the content type. + + For example, the line: + + DESCRIPTION:This is a long description that exists on a long line. + + Can be represented as: + + DESCRIPTION:This is a lo + ng description + that exists on a long line. + + The process of moving from this folded multiple-line representation + to its single-line representation is called "unfolding". Unfolding + is accomplished by removing the CRLF and the linear white-space + character that immediately follows. + + + + + +Desruisseaux Standards Track [Page 9] + +RFC 5545 iCalendar September 2009 + + + When parsing a content line, folded lines MUST first be unfolded + according to the unfolding procedure described above. + + Note: It is possible for very simple implementations to generate + improperly folded lines in the middle of a UTF-8 multi-octet + sequence. For this reason, implementations need to unfold lines + in such a way to properly restore the original sequence. + + The content information associated with an iCalendar object is + formatted using a syntax similar to that defined by [RFC2425]. That + is, the content information consists of CRLF-separated content lines. + + The following notation defines the lines of content in an iCalendar + object: + + contentline = name *(";" param ) ":" value CRLF + ; This ABNF is just a general definition for an initial parsing + ; of the content line into its property name, parameter list, + ; and value string + + ; When parsing a content line, folded lines MUST first + ; be unfolded according to the unfolding procedure + ; described above. When generating a content line, lines + ; longer than 75 octets SHOULD be folded according to + ; the folding procedure described above. + + name = iana-token / x-name + + iana-token = 1*(ALPHA / DIGIT / "-") + ; iCalendar identifier registered with IANA + + x-name = "X-" [vendorid "-"] 1*(ALPHA / DIGIT / "-") + ; Reserved for experimental use. + + vendorid = 3*(ALPHA / DIGIT) + ; Vendor identification + + param = param-name "=" param-value *("," param-value) + ; Each property defines the specific ABNF for the parameters + ; allowed on the property. Refer to specific properties for + ; precise parameter ABNF. + + param-name = iana-token / x-name + + param-value = paramtext / quoted-string + + paramtext = *SAFE-CHAR + + + + +Desruisseaux Standards Track [Page 10] + +RFC 5545 iCalendar September 2009 + + + value = *VALUE-CHAR + + quoted-string = DQUOTE *QSAFE-CHAR DQUOTE + + QSAFE-CHAR = WSP / %x21 / %x23-7E / NON-US-ASCII + ; Any character except CONTROL and DQUOTE + + SAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-7E + / NON-US-ASCII + ; Any character except CONTROL, DQUOTE, ";", ":", "," + + VALUE-CHAR = WSP / %x21-7E / NON-US-ASCII + ; Any textual character + + NON-US-ASCII = UTF8-2 / UTF8-3 / UTF8-4 + ; UTF8-2, UTF8-3, and UTF8-4 are defined in [RFC3629] + + CONTROL = %x00-08 / %x0A-1F / %x7F + ; All the controls except HTAB + + The property value component of a content line has a format that is + property specific. Refer to the section describing each property for + a definition of this format. + + All names of properties, property parameters, enumerated property + values and property parameter values are case-insensitive. However, + all other property values are case-sensitive, unless otherwise + stated. + +3.1.1. List and Field Separators + + Some properties and parameters allow a list of values. Values in a + list of values MUST be separated by a COMMA character. There is no + significance to the order of values in a list. For those parameter + values (such as those that specify URI values) that are specified in + quoted-strings, the individual quoted-strings are separated by a + COMMA character. + + Some property values are defined in terms of multiple parts. These + structured property values MUST have their value parts separated by a + SEMICOLON character. + + Some properties allow a list of parameters. Each property parameter + in a list of property parameters MUST be separated by a SEMICOLON + character. + + + + + + +Desruisseaux Standards Track [Page 11] + +RFC 5545 iCalendar September 2009 + + + Property parameters with values containing a COLON character, a + SEMICOLON character or a COMMA character MUST be placed in quoted + text. + + For example, in the following properties, a SEMICOLON is used to + separate property parameters from each other and a COMMA character is + used to separate property values in a value list. + + ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT:mailto: + jsmith@example.com + + RDATE;VALUE=DATE:19970304,19970504,19970704,19970904 + +3.1.2. Multiple Values + + Some properties defined in the iCalendar object can have multiple + values. The general rule for encoding multi-valued items is to + simply create a new content line for each value, including the + property name. However, it should be noted that some properties + support encoding multiple values in a single property by separating + the values with a COMMA character. Individual property definitions + should be consulted for determining whether a specific property + allows multiple values and in which of these two forms. Multi-valued + properties MUST NOT be used to specify multiple language variants of + the same value. Calendar applications SHOULD display all values. + +3.1.3. Binary Content + + Binary content information in an iCalendar object SHOULD be + referenced using a URI within a property value. That is, the binary + content information SHOULD be placed in an external MIME entity that + can be referenced by a URI from within the iCalendar object. In + applications where this is not feasible, binary content information + can be included within an iCalendar object, but only after first + encoding it into text using the "BASE64" encoding method defined in + [RFC4648]. Inline binary content SHOULD only be used in applications + whose special circumstances demand that an iCalendar object be + expressed as a single entity. A property containing inline binary + content information MUST specify the "ENCODING" property parameter. + Binary content information placed external to the iCalendar object + MUST be referenced by a uniform resource identifier (URI). + + The following example specifies an "ATTACH" property that references + an attachment external to the iCalendar object with a URI reference: + + ATTACH:http://example.com/public/quarterly-report.doc + + + + + +Desruisseaux Standards Track [Page 12] + +RFC 5545 iCalendar September 2009 + + + The following example specifies an "ATTACH" property with inline + binary encoded content information: + + ATTACH;FMTTYPE=text/plain;ENCODING=BASE64;VALUE=BINARY:VGhlIH + F1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZy4 + +3.1.4. Character Set + + There is not a property parameter to declare the charset used in a + property value. The default charset for an iCalendar stream is UTF-8 + as defined in [RFC3629]. + + The "charset" Content-Type parameter MUST be used in MIME transports + to specify the charset being used. + +3.2. Property Parameters + + A property can have attributes with which it is associated. These + "property parameters" contain meta-information about the property or + the property value. Property parameters are provided to specify such + information as the location of an alternate text representation for a + property value, the language of a text property value, the value type + of the property value, and other attributes. + + Property parameter values that contain the COLON, SEMICOLON, or COMMA + character separators MUST be specified as quoted-string text values. + Property parameter values MUST NOT contain the DQUOTE character. The + DQUOTE character is used as a delimiter for parameter values that + contain restricted characters or URI text. For example: + + DESCRIPTION;ALTREP="cid:part1.0001@example.org":The Fall'98 Wild + Wizards Conference - - Las Vegas\, NV\, USA + + Property parameter values that are not in quoted-strings are case- + insensitive. + + The general property parameters defined by this memo are defined by + the following notation: + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 13] + +RFC 5545 iCalendar September 2009 + + + icalparameter = altrepparam ; Alternate text representation + / cnparam ; Common name + / cutypeparam ; Calendar user type + / delfromparam ; Delegator + / deltoparam ; Delegatee + / dirparam ; Directory entry + / encodingparam ; Inline encoding + / fmttypeparam ; Format type + / fbtypeparam ; Free/busy time type + / languageparam ; Language for text + / memberparam ; Group or list membership + / partstatparam ; Participation status + / rangeparam ; Recurrence identifier range + / trigrelparam ; Alarm trigger relationship + / reltypeparam ; Relationship type + / roleparam ; Participation role + / rsvpparam ; RSVP expectation + / sentbyparam ; Sent by + / tzidparam ; Reference to time zone object + / valuetypeparam ; Property value data type + / other-param + + other-param = (iana-param / x-param) + + iana-param = iana-token "=" param-value *("," param-value) + ; Some other IANA-registered iCalendar parameter. + + x-param = x-name "=" param-value *("," param-value) + ; A non-standard, experimental parameter. + + Applications MUST ignore x-param and iana-param values they don't + recognize. + +3.2.1. Alternate Text Representation + + Parameter Name: ALTREP + + Purpose: To specify an alternate text representation for the + property value. + + Format Definition: This property parameter is defined by the + following notation: + + altrepparam = "ALTREP" "=" DQUOTE uri DQUOTE + + Description: This parameter specifies a URI that points to an + alternate representation for a textual property value. A property + specifying this parameter MUST also include a value that reflects + + + +Desruisseaux Standards Track [Page 14] + +RFC 5545 iCalendar September 2009 + + + the default representation of the text value. The URI parameter + value MUST be specified in a quoted-string. + + Note: While there is no restriction imposed on the URI schemes + allowed for this parameter, Content Identifier (CID) [RFC2392], + HTTP [RFC2616], and HTTPS [RFC2818] are the URI schemes most + commonly used by current implementations. + + Example: + + DESCRIPTION;ALTREP="CID:part3.msg.970415T083000@example.com": + Project XYZ Review Meeting will include the following agenda + items: (a) Market Overview\, (b) Finances\, (c) Project Man + agement + + The "ALTREP" property parameter value might point to a "text/html" + content portion. + + Content-Type:text/html + Content-Id: + + + + + + +

+ Project XYZ Review Meeting will include + the following agenda items: +

    +
  1. Market Overview
    2. +
  2. Finances
    3. +
  3. Project Management
    4. +
+

+ + + +3.2.2. Common Name + + Parameter Name: CN + + Purpose: To specify the common name to be associated with the + calendar user specified by the property. + + Format Definition: This property parameter is defined by the + following notation: + + + + +Desruisseaux Standards Track [Page 15] + +RFC 5545 iCalendar September 2009 + + + cnparam = "CN" "=" param-value + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. The parameter specifies the common name + to be associated with the calendar user specified by the property. + The parameter value is text. The parameter value can be used for + display text to be associated with the calendar address specified + by the property. + + Example: + + ORGANIZER;CN="John Smith":mailto:jsmith@example.com + +3.2.3. Calendar User Type + + Parameter Name: CUTYPE + + Purpose: To identify the type of calendar user specified by the + property. + + Format Definition: This property parameter is defined by the + following notation: + + cutypeparam = "CUTYPE" "=" + ("INDIVIDUAL" ; An individual + / "GROUP" ; A group of individuals + / "RESOURCE" ; A physical resource + / "ROOM" ; A room resource + / "UNKNOWN" ; Otherwise not known + / x-name ; Experimental type + / iana-token) ; Other IANA-registered + ; type + ; Default is INDIVIDUAL + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. The parameter identifies the type of + calendar user specified by the property. If not specified on a + property that allows this parameter, the default is INDIVIDUAL. + Applications MUST treat x-name and iana-token values they don't + recognize the same way as they would the UNKNOWN value. + + Example: + + ATTENDEE;CUTYPE=GROUP:mailto:ietf-calsch@example.org + + + + + + + +Desruisseaux Standards Track [Page 16] + +RFC 5545 iCalendar September 2009 + + +3.2.4. Delegators + + Parameter Name: DELEGATED-FROM + + Purpose: To specify the calendar users that have delegated their + participation to the calendar user specified by the property. + + Format Definition: This property parameter is defined by the + following notation: + + delfromparam = "DELEGATED-FROM" "=" DQUOTE cal-address + DQUOTE *("," DQUOTE cal-address DQUOTE) + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. This parameter specifies those calendar + users that have delegated their participation in a group-scheduled + event or to-do to the calendar user specified by the property. + The individual calendar address parameter values MUST each be + specified in a quoted-string. + + Example: + + ATTENDEE;DELEGATED-FROM="mailto:jsmith@example.com":mailto: + jdoe@example.com + +3.2.5. Delegatees + + Parameter Name: DELEGATED-TO + + Purpose: To specify the calendar users to whom the calendar user + specified by the property has delegated participation. + + Format Definition: This property parameter is defined by the + following notation: + + deltoparam = "DELEGATED-TO" "=" DQUOTE cal-address DQUOTE + *("," DQUOTE cal-address DQUOTE) + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. This parameter specifies those calendar + users whom have been delegated participation in a group-scheduled + event or to-do by the calendar user specified by the property. + The individual calendar address parameter values MUST each be + specified in a quoted-string. + + + + + + + +Desruisseaux Standards Track [Page 17] + +RFC 5545 iCalendar September 2009 + + + Example: + + ATTENDEE;DELEGATED-TO="mailto:jdoe@example.com","mailto:jqpublic + @example.com":mailto:jsmith@example.com + +3.2.6. Directory Entry Reference + + Parameter Name: DIR + + Purpose: To specify reference to a directory entry associated with + the calendar user specified by the property. + + Format Definition: This property parameter is defined by the + following notation: + + dirparam = "DIR" "=" DQUOTE uri DQUOTE + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. The parameter specifies a reference to + the directory entry associated with the calendar user specified by + the property. The parameter value is a URI. The URI parameter + value MUST be specified in a quoted-string. + + Note: While there is no restriction imposed on the URI schemes + allowed for this parameter, CID [RFC2392], DATA [RFC2397], FILE + [RFC1738], FTP [RFC1738], HTTP [RFC2616], HTTPS [RFC2818], LDAP + [RFC4516], and MID [RFC2392] are the URI schemes most commonly + used by current implementations. + + Example: + + ORGANIZER;DIR="ldap://example.com:6666/o=ABC%20Industries, + c=US???(cn=Jim%20Dolittle)":mailto:jimdo@example.com + +3.2.7. Inline Encoding + + Parameter Name: ENCODING + + Purpose: To specify an alternate inline encoding for the property + value. + + Format Definition: This property parameter is defined by the + following notation: + + + + + + + + +Desruisseaux Standards Track [Page 18] + +RFC 5545 iCalendar September 2009 + + + encodingparam = "ENCODING" "=" + ( "8BIT" + ; "8bit" text encoding is defined in [RFC2045] + / "BASE64" + ; "BASE64" binary encoding format is defined in [RFC4648] + ) + + Description: This property parameter identifies the inline encoding + used in a property value. The default encoding is "8BIT", + corresponding to a property value consisting of text. The + "BASE64" encoding type corresponds to a property value encoded + using the "BASE64" encoding defined in [RFC2045]. + + If the value type parameter is ";VALUE=BINARY", then the inline + encoding parameter MUST be specified with the value + ";ENCODING=BASE64". + + Example: + + ATTACH;FMTTYPE=text/plain;ENCODING=BASE64;VALUE=BINARY:TG9yZW + 0gaXBzdW0gZG9sb3Igc2l0IGFtZXQsIGNvbnNlY3RldHVyIGFkaXBpc2ljaW + 5nIGVsaXQsIHNlZCBkbyBlaXVzbW9kIHRlbXBvciBpbmNpZGlkdW50IHV0IG + xhYm9yZSBldCBkb2xvcmUgbWFnbmEgYWxpcXVhLiBVdCBlbmltIGFkIG1pbm + ltIHZlbmlhbSwgcXVpcyBub3N0cnVkIGV4ZXJjaXRhdGlvbiB1bGxhbWNvIG + xhYm9yaXMgbmlzaSB1dCBhbGlxdWlwIGV4IGVhIGNvbW1vZG8gY29uc2VxdW + F0LiBEdWlzIGF1dGUgaXJ1cmUgZG9sb3IgaW4gcmVwcmVoZW5kZXJpdCBpbi + B2b2x1cHRhdGUgdmVsaXQgZXNzZSBjaWxsdW0gZG9sb3JlIGV1IGZ1Z2lhdC + BudWxsYSBwYXJpYXR1ci4gRXhjZXB0ZXVyIHNpbnQgb2NjYWVjYXQgY3VwaW + RhdGF0IG5vbiBwcm9pZGVudCwgc3VudCBpbiBjdWxwYSBxdWkgb2ZmaWNpYS + BkZXNlcnVudCBtb2xsaXQgYW5pbSBpZCBlc3QgbGFib3J1bS4= + +3.2.8. Format Type + + Parameter Name: FMTTYPE + + Purpose: To specify the content type of a referenced object. + + Format Definition: This property parameter is defined by the + following notation: + + fmttypeparam = "FMTTYPE" "=" type-name "/" subtype-name + ; Where "type-name" and "subtype-name" are + ; defined in Section 4.2 of [RFC4288]. + + Description: This parameter can be specified on properties that are + used to reference an object. The parameter specifies the media + type [RFC4288] of the referenced object. For example, on the + "ATTACH" property, an FTP type URI value does not, by itself, + + + +Desruisseaux Standards Track [Page 19] + +RFC 5545 iCalendar September 2009 + + + necessarily convey the type of content associated with the + resource. The parameter value MUST be the text for either an + IANA-registered media type or a non-standard media type. + + Example: + + ATTACH;FMTTYPE=application/msword:ftp://example.com/pub/docs/ + agenda.doc + +3.2.9. Free/Busy Time Type + + Parameter Name: FBTYPE + + Purpose: To specify the free or busy time type. + + Format Definition: This property parameter is defined by the + following notation: + + fbtypeparam = "FBTYPE" "=" ("FREE" / "BUSY" + / "BUSY-UNAVAILABLE" / "BUSY-TENTATIVE" + / x-name + ; Some experimental iCalendar free/busy type. + / iana-token) + ; Some other IANA-registered iCalendar free/busy type. + + Description: This parameter specifies the free or busy time type. + The value FREE indicates that the time interval is free for + scheduling. The value BUSY indicates that the time interval is + busy because one or more events have been scheduled for that + interval. The value BUSY-UNAVAILABLE indicates that the time + interval is busy and that the interval can not be scheduled. The + value BUSY-TENTATIVE indicates that the time interval is busy + because one or more events have been tentatively scheduled for + that interval. If not specified on a property that allows this + parameter, the default is BUSY. Applications MUST treat x-name + and iana-token values they don't recognize the same way as they + would the BUSY value. + + Example: The following is an example of this parameter on a + "FREEBUSY" property. + + FREEBUSY;FBTYPE=BUSY:19980415T133000Z/19980415T170000Z + + + + + + + + + +Desruisseaux Standards Track [Page 20] + +RFC 5545 iCalendar September 2009 + + +3.2.10. Language + + Parameter Name: LANGUAGE + + Purpose: To specify the language for text values in a property or + property parameter. + + Format Definition: This property parameter is defined by the + following notation: + + languageparam = "LANGUAGE" "=" language + + language = Language-Tag + ; As defined in [RFC5646]. + + Description: This parameter identifies the language of the text in + the property value and of all property parameter values of the + property. The value of the "LANGUAGE" property parameter is that + defined in [RFC5646]. + + For transport in a MIME entity, the Content-Language header field + can be used to set the default language for the entire body part. + Otherwise, no default language is assumed. + + Example: The following are examples of this parameter on the + "SUMMARY" and "LOCATION" properties: + + SUMMARY;LANGUAGE=en-US:Company Holiday Party + + LOCATION;LANGUAGE=en:Germany + + LOCATION;LANGUAGE=no:Tyskland + +3.2.11. Group or List Membership + + Parameter Name: MEMBER + + Purpose: To specify the group or list membership of the calendar + user specified by the property. + + Format Definition: This property parameter is defined by the + following notation: + + memberparam = "MEMBER" "=" DQUOTE cal-address DQUOTE + *("," DQUOTE cal-address DQUOTE) + + + + + + +Desruisseaux Standards Track [Page 21] + +RFC 5545 iCalendar September 2009 + + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. The parameter identifies the groups or + list membership for the calendar user specified by the property. + The parameter value is either a single calendar address in a + quoted-string or a COMMA-separated list of calendar addresses, + each in a quoted-string. The individual calendar address + parameter values MUST each be specified in a quoted-string. + + Example: + + ATTENDEE;MEMBER="mailto:ietf-calsch@example.org":mailto: + jsmith@example.com + + ATTENDEE;MEMBER="mailto:projectA@example.com","mailto:pr + ojectB@example.com":mailto:janedoe@example.com + +3.2.12. Participation Status + + Parameter Name: PARTSTAT + + Purpose: To specify the participation status for the calendar user + specified by the property. + + Format Definition: This property parameter is defined by the + following notation: + + partstatparam = "PARTSTAT" "=" + (partstat-event + / partstat-todo + / partstat-jour) + + partstat-event = ("NEEDS-ACTION" ; Event needs action + / "ACCEPTED" ; Event accepted + / "DECLINED" ; Event declined + / "TENTATIVE" ; Event tentatively + ; accepted + / "DELEGATED" ; Event delegated + / x-name ; Experimental status + / iana-token) ; Other IANA-registered + ; status + ; These are the participation statuses for a "VEVENT". + ; Default is NEEDS-ACTION. + + partstat-todo = ("NEEDS-ACTION" ; To-do needs action + / "ACCEPTED" ; To-do accepted + / "DECLINED" ; To-do declined + / "TENTATIVE" ; To-do tentatively + ; accepted + + + +Desruisseaux Standards Track [Page 22] + +RFC 5545 iCalendar September 2009 + + + / "DELEGATED" ; To-do delegated + / "COMPLETED" ; To-do completed + ; COMPLETED property has + ; DATE-TIME completed + / "IN-PROCESS" ; To-do in process of + ; being completed + / x-name ; Experimental status + / iana-token) ; Other IANA-registered + ; status + ; These are the participation statuses for a "VTODO". + ; Default is NEEDS-ACTION. + + + + partstat-jour = ("NEEDS-ACTION" ; Journal needs action + / "ACCEPTED" ; Journal accepted + / "DECLINED" ; Journal declined + / x-name ; Experimental status + / iana-token) ; Other IANA-registered + ; status + ; These are the participation statuses for a "VJOURNAL". + ; Default is NEEDS-ACTION. + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. The parameter identifies the + participation status for the calendar user specified by the + property value. The parameter values differ depending on whether + they are associated with a group-scheduled "VEVENT", "VTODO", or + "VJOURNAL". The values MUST match one of the values allowed for + the given calendar component. If not specified on a property that + allows this parameter, the default value is NEEDS-ACTION. + Applications MUST treat x-name and iana-token values they don't + recognize the same way as they would the NEEDS-ACTION value. + + Example: + + ATTENDEE;PARTSTAT=DECLINED:mailto:jsmith@example.com + +3.2.13. Recurrence Identifier Range + + Parameter Name: RANGE + + Purpose: To specify the effective range of recurrence instances from + the instance specified by the recurrence identifier specified by + the property. + + Format Definition: This property parameter is defined by the + following notation: + + + +Desruisseaux Standards Track [Page 23] + +RFC 5545 iCalendar September 2009 + + + rangeparam = "RANGE" "=" "THISANDFUTURE" + ; To specify the instance specified by the recurrence identifier + ; and all subsequent recurrence instances. + + Description: This parameter can be specified on a property that + specifies a recurrence identifier. The parameter specifies the + effective range of recurrence instances that is specified by the + property. The effective range is from the recurrence identifier + specified by the property. If this parameter is not specified on + an allowed property, then the default range is the single instance + specified by the recurrence identifier value of the property. The + parameter value can only be "THISANDFUTURE" to indicate a range + defined by the recurrence identifier and all subsequent instances. + The value "THISANDPRIOR" is deprecated by this revision of + iCalendar and MUST NOT be generated by applications. + + Example: + + RECURRENCE-ID;RANGE=THISANDFUTURE:19980401T133000Z + +3.2.14. Alarm Trigger Relationship + + Parameter Name: RELATED + + Purpose: To specify the relationship of the alarm trigger with + respect to the start or end of the calendar component. + + Format Definition: This property parameter is defined by the + following notation: + + trigrelparam = "RELATED" "=" + ("START" ; Trigger off of start + / "END") ; Trigger off of end + + Description: This parameter can be specified on properties that + specify an alarm trigger with a "DURATION" value type. The + parameter specifies whether the alarm will trigger relative to the + start or end of the calendar component. The parameter value START + will set the alarm to trigger off the start of the calendar + component; the parameter value END will set the alarm to trigger + off the end of the calendar component. If the parameter is not + specified on an allowable property, then the default is START. + + Example: + + TRIGGER;RELATED=END:PT5M + + + + + +Desruisseaux Standards Track [Page 24] + +RFC 5545 iCalendar September 2009 + + +3.2.15. Relationship Type + + Parameter Name: RELTYPE + + Purpose: To specify the type of hierarchical relationship associated + with the calendar component specified by the property. + + Format Definition: This property parameter is defined by the + following notation: + + reltypeparam = "RELTYPE" "=" + ("PARENT" ; Parent relationship - Default + / "CHILD" ; Child relationship + / "SIBLING" ; Sibling relationship + / iana-token ; Some other IANA-registered + ; iCalendar relationship type + / x-name) ; A non-standard, experimental + ; relationship type + + Description: This parameter can be specified on a property that + references another related calendar. The parameter specifies the + hierarchical relationship type of the calendar component + referenced by the property. The parameter value can be PARENT, to + indicate that the referenced calendar component is a superior of + calendar component; CHILD to indicate that the referenced calendar + component is a subordinate of the calendar component; or SIBLING + to indicate that the referenced calendar component is a peer of + the calendar component. If this parameter is not specified on an + allowable property, the default relationship type is PARENT. + Applications MUST treat x-name and iana-token values they don't + recognize the same way as they would the PARENT value. + + Example: + + RELATED-TO;RELTYPE=SIBLING:19960401-080045-4000F192713@ + example.com + +3.2.16. Participation Role + + Parameter Name: ROLE + + Purpose: To specify the participation role for the calendar user + specified by the property. + + Format Definition: This property parameter is defined by the + following notation: + + + + + +Desruisseaux Standards Track [Page 25] + +RFC 5545 iCalendar September 2009 + + + roleparam = "ROLE" "=" + ("CHAIR" ; Indicates chair of the + ; calendar entity + / "REQ-PARTICIPANT" ; Indicates a participant whose + ; participation is required + / "OPT-PARTICIPANT" ; Indicates a participant whose + ; participation is optional + / "NON-PARTICIPANT" ; Indicates a participant who + ; is copied for information + ; purposes only + / x-name ; Experimental role + / iana-token) ; Other IANA role + ; Default is REQ-PARTICIPANT + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. The parameter specifies the participation + role for the calendar user specified by the property in the group + schedule calendar component. If not specified on a property that + allows this parameter, the default value is REQ-PARTICIPANT. + Applications MUST treat x-name and iana-token values they don't + recognize the same way as they would the REQ-PARTICIPANT value. + + Example: + + ATTENDEE;ROLE=CHAIR:mailto:mrbig@example.com + +3.2.17. RSVP Expectation + + Parameter Name: RSVP + + Purpose: To specify whether there is an expectation of a favor of a + reply from the calendar user specified by the property value. + + Format Definition: This property parameter is defined by the + following notation: + + rsvpparam = "RSVP" "=" ("TRUE" / "FALSE") + ; Default is FALSE + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. The parameter identifies the expectation + of a reply from the calendar user specified by the property value. + This parameter is used by the "Organizer" to request a + participation status reply from an "Attendee" of a group-scheduled + event or to-do. If not specified on a property that allows this + parameter, the default value is FALSE. + + + + + +Desruisseaux Standards Track [Page 26] + +RFC 5545 iCalendar September 2009 + + + Example: + + ATTENDEE;RSVP=TRUE:mailto:jsmith@example.com + +3.2.18. Sent By + + Parameter Name: SENT-BY + + Purpose: To specify the calendar user that is acting on behalf of + the calendar user specified by the property. + + Format Definition: This property parameter is defined by the + following notation: + + sentbyparam = "SENT-BY" "=" DQUOTE cal-address DQUOTE + + Description: This parameter can be specified on properties with a + CAL-ADDRESS value type. The parameter specifies the calendar user + that is acting on behalf of the calendar user specified by the + property. The parameter value MUST be a mailto URI as defined in + [RFC2368]. The individual calendar address parameter values MUST + each be specified in a quoted-string. + + Example: + + ORGANIZER;SENT-BY="mailto:sray@example.com":mailto: + jsmith@example.com + +3.2.19. Time Zone Identifier + + Parameter Name: TZID + + Purpose: To specify the identifier for the time zone definition for + a time component in the property value. + + Format Definition: This property parameter is defined by the + following notation: + + tzidparam = "TZID" "=" [tzidprefix] paramtext + + tzidprefix = "/" + + Description: This parameter MUST be specified on the "DTSTART", + "DTEND", "DUE", "EXDATE", and "RDATE" properties when either a + DATE-TIME or TIME value type is specified and when the value is + neither a UTC or a "floating" time. Refer to the DATE-TIME or + TIME value type definition for a description of UTC and "floating + time" formats. This property parameter specifies a text value + + + +Desruisseaux Standards Track [Page 27] + +RFC 5545 iCalendar September 2009 + + + that uniquely identifies the "VTIMEZONE" calendar component to be + used when evaluating the time portion of the property. The value + of the "TZID" property parameter will be equal to the value of the + "TZID" property for the matching time zone definition. An + individual "VTIMEZONE" calendar component MUST be specified for + each unique "TZID" parameter value specified in the iCalendar + object. + + The parameter MUST be specified on properties with a DATE-TIME + value if the DATE-TIME is not either a UTC or a "floating" time. + Failure to include and follow VTIMEZONE definitions in iCalendar + objects may lead to inconsistent understanding of the local time + at any given location. + + The presence of the SOLIDUS character as a prefix, indicates that + this "TZID" represents a unique ID in a globally defined time zone + registry (when such registry is defined). + + Note: This document does not define a naming convention for + time zone identifiers. Implementers may want to use the naming + conventions defined in existing time zone specifications such + as the public-domain TZ database [TZDB]. The specification of + globally unique time zone identifiers is not addressed by this + document and is left for future study. + + The following are examples of this property parameter: + + DTSTART;TZID=America/New_York:19980119T020000 + + DTEND;TZID=America/New_York:19980119T030000 + + The "TZID" property parameter MUST NOT be applied to DATE + properties and DATE-TIME or TIME properties whose time values are + specified in UTC. + + The use of local time in a DATE-TIME or TIME value without the + "TZID" property parameter is to be interpreted as floating time, + regardless of the existence of "VTIMEZONE" calendar components in + the iCalendar object. + + For more information, see the sections on the value types DATE- + TIME and TIME. + + + + + + + + + +Desruisseaux Standards Track [Page 28] + +RFC 5545 iCalendar September 2009 + + +3.2.20. Value Data Types + + Parameter Name: VALUE + + Purpose: To explicitly specify the value type format for a property + value. + + Format Definition: This property parameter is defined by the + following notation: + + valuetypeparam = "VALUE" "=" valuetype + + valuetype = ("BINARY" + / "BOOLEAN" + / "CAL-ADDRESS" + / "DATE" + / "DATE-TIME" + / "DURATION" + / "FLOAT" + / "INTEGER" + / "PERIOD" + / "RECUR" + / "TEXT" + / "TIME" + / "URI" + / "UTC-OFFSET" + / x-name + ; Some experimental iCalendar value type. + / iana-token) + ; Some other IANA-registered iCalendar value type. + + Description: This parameter specifies the value type and format of + the property value. The property values MUST be of a single value + type. For example, a "RDATE" property cannot have a combination + of DATE-TIME and TIME value types. + + If the property's value is the default value type, then this + parameter need not be specified. However, if the property's + default value type is overridden by some other allowable value + type, then this parameter MUST be specified. + + Applications MUST preserve the value data for x-name and iana- + token values that they don't recognize without attempting to + interpret or parse the value data. + + + + + + + +Desruisseaux Standards Track [Page 29] + +RFC 5545 iCalendar September 2009 + + +3.3. Property Value Data Types + + The properties in an iCalendar object are strongly typed. The + definition of each property restricts the value to be one of the + value data types, or simply value types, defined in this section. + The value type for a property will either be specified implicitly as + the default value type or will be explicitly specified with the + "VALUE" parameter. If the value type of a property is one of the + alternate valid types, then it MUST be explicitly specified with the + "VALUE" parameter. + +3.3.1. Binary + + Value Name: BINARY + + Purpose: This value type is used to identify properties that contain + a character encoding of inline binary data. For example, an + inline attachment of a document might be included in an iCalendar + object. + + Format Definition: This value type is defined by the following + notation: + + binary = *(4b-char) [b-end] + ; A "BASE64" encoded character string, as defined by [RFC4648]. + + b-end = (2b-char "==") / (3b-char "=") + + b-char = ALPHA / DIGIT / "+" / "/" + + Description: Property values with this value type MUST also include + the inline encoding parameter sequence of ";ENCODING=BASE64". + That is, all inline binary data MUST first be character encoded + using the "BASE64" encoding method defined in [RFC2045]. No + additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) is defined for this value type. + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 30] + +RFC 5545 iCalendar September 2009 + + + Example: The following is an example of a "BASE64" encoded binary + value data: + + ATTACH;FMTTYPE=image/vnd.microsoft.icon;ENCODING=BASE64;VALUE + =BINARY:AAABAAEAEBAQAAEABAAoAQAAFgAAACgAAAAQAAAAIAAAAAEABAAA + AAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAAAAgIAAAICAgADAwMAA////AAAA + AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA + AAAAAAAAAAAAAAAAAAAAAAMwAAAAAAABNEMQAAAAAAAkQgAAAAAAJEREQgAA + ACECQ0QgEgAAQxQzM0E0AABERCRCREQAADRDJEJEQwAAAhA0QwEQAAAAAERE + AAAAAAAAREQAAAAAAAAkQgAAAAAAAAMgAAAAAAAAAAAAAAAAAAAAAAAAAAAA + AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA + AAAAAAAAAAAA + +3.3.2. Boolean + + Value Name: BOOLEAN + + Purpose: This value type is used to identify properties that contain + either a "TRUE" or "FALSE" Boolean value. + + Format Definition: This value type is defined by the following + notation: + + boolean = "TRUE" / "FALSE" + + Description: These values are case-insensitive text. No additional + content value encoding (i.e., BACKSLASH character encoding, see + Section 3.3.11) is defined for this value type. + + Example: The following is an example of a hypothetical property that + has a BOOLEAN value type: + + TRUE + +3.3.3. Calendar User Address + + Value Name: CAL-ADDRESS + + Purpose: This value type is used to identify properties that contain + a calendar user address. + + Format Definition: This value type is defined by the following + notation: + + cal-address = uri + + Description: The value is a URI as defined by [RFC3986] or any other + IANA-registered form for a URI. When used to address an Internet + + + +Desruisseaux Standards Track [Page 31] + +RFC 5545 iCalendar September 2009 + + + email transport address for a calendar user, the value MUST be a + mailto URI, as defined by [RFC2368]. No additional content value + encoding (i.e., BACKSLASH character encoding, see Section 3.3.11) + is defined for this value type. + + Example: + + mailto:jane_doe@example.com + +3.3.4. Date + + Value Name: DATE + + Purpose: This value type is used to identify values that contain a + calendar date. + + Format Definition: This value type is defined by the following + notation: + + date = date-value + + date-value = date-fullyear date-month date-mday + date-fullyear = 4DIGIT + date-month = 2DIGIT ;01-12 + date-mday = 2DIGIT ;01-28, 01-29, 01-30, 01-31 + ;based on month/year + + Description: If the property permits, multiple "date" values are + specified as a COMMA-separated list of values. The format for the + value type is based on the [ISO.8601.2004] complete + representation, basic format for a calendar date. The textual + format specifies a four-digit year, two-digit month, and two-digit + day of the month. There are no separator characters between the + year, month, and day component text. + + No additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) is defined for this value type. + + Example: The following represents July 14, 1997: + + 19970714 + +3.3.5. Date-Time + + Value Name: DATE-TIME + + Purpose: This value type is used to identify values that specify a + precise calendar date and time of day. + + + +Desruisseaux Standards Track [Page 32] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This value type is defined by the following + notation: + + date-time = date "T" time ;As specified in the DATE and TIME + ;value definitions + + Description: If the property permits, multiple "DATE-TIME" values + are specified as a COMMA-separated list of values. No additional + content value encoding (i.e., BACKSLASH character encoding, see + Section 3.3.11) is defined for this value type. + + The "DATE-TIME" value type is used to identify values that contain + a precise calendar date and time of day. The format is based on + the [ISO.8601.2004] complete representation, basic format for a + calendar date and time of day. The text format is a concatenation + of the "date", followed by the LATIN CAPITAL LETTER T character, + the time designator, followed by the "time" format. + + The "DATE-TIME" value type expresses time values in three forms: + + The form of date and time with UTC offset MUST NOT be used. For + example, the following is not valid for a DATE-TIME value: + + 19980119T230000-0800 ;Invalid time format + + FORM #1: DATE WITH LOCAL TIME + + The date with local time form is simply a DATE-TIME value that + does not contain the UTC designator nor does it reference a time + zone. For example, the following represents January 18, 1998, at + 11 PM: + + 19980118T230000 + + DATE-TIME values of this type are said to be "floating" and are + not bound to any time zone in particular. They are used to + represent the same hour, minute, and second value regardless of + which time zone is currently being observed. For example, an + event can be defined that indicates that an individual will be + busy from 11:00 AM to 1:00 PM every day, no matter which time zone + the person is in. In these cases, a local time can be specified. + The recipient of an iCalendar object with a property value + consisting of a local time, without any relative time zone + information, SHOULD interpret the value as being fixed to whatever + time zone the "ATTENDEE" is in at any given moment. This means + that two "Attendees", in different time zones, receiving the same + event definition as a floating time, may be participating in the + + + + +Desruisseaux Standards Track [Page 33] + +RFC 5545 iCalendar September 2009 + + + event at different actual times. Floating time SHOULD only be + used where that is the reasonable behavior. + + In most cases, a fixed time is desired. To properly communicate a + fixed time in a property value, either UTC time or local time with + time zone reference MUST be specified. + + The use of local time in a DATE-TIME value without the "TZID" + property parameter is to be interpreted as floating time, + regardless of the existence of "VTIMEZONE" calendar components in + the iCalendar object. + + FORM #2: DATE WITH UTC TIME + + The date with UTC time, or absolute time, is identified by a LATIN + CAPITAL LETTER Z suffix character, the UTC designator, appended to + the time value. For example, the following represents January 19, + 1998, at 0700 UTC: + + 19980119T070000Z + + The "TZID" property parameter MUST NOT be applied to DATE-TIME + properties whose time values are specified in UTC. + + FORM #3: DATE WITH LOCAL TIME AND TIME ZONE REFERENCE + + The date and local time with reference to time zone information is + identified by the use the "TZID" property parameter to reference + the appropriate time zone definition. "TZID" is discussed in + detail in Section 3.2.19. For example, the following represents + 2:00 A.M. in New York on January 19, 1998: + + TZID=America/New_York:19980119T020000 + + If, based on the definition of the referenced time zone, the local + time described occurs more than once (when changing from daylight + to standard time), the DATE-TIME value refers to the first + occurrence of the referenced time. Thus, TZID=America/ + New_York:20071104T013000 indicates November 4, 2007 at 1:30 A.M. + EDT (UTC-04:00). If the local time described does not occur (when + changing from standard to daylight time), the DATE-TIME value is + interpreted using the UTC offset before the gap in local times. + Thus, TZID=America/New_York:20070311T023000 indicates March 11, + 2007 at 3:30 A.M. EDT (UTC-04:00), one hour after 1:30 A.M. EST + (UTC-05:00). + + + + + + +Desruisseaux Standards Track [Page 34] + +RFC 5545 iCalendar September 2009 + + + A time value MUST only specify the second 60 when specifying a + positive leap second. For example: + + 19970630T235960Z + + Implementations that do not support leap seconds SHOULD interpret + the second 60 as equivalent to the second 59. + + Example: The following represents July 14, 1997, at 1:30 PM in New + York City in each of the three time formats, using the "DTSTART" + property. + + DTSTART:19970714T133000 ; Local time + DTSTART:19970714T173000Z ; UTC time + DTSTART;TZID=America/New_York:19970714T133000 + ; Local time and time + ; zone reference + +3.3.6. Duration + + Value Name: DURATION + + Purpose: This value type is used to identify properties that contain + a duration of time. + + Format Definition: This value type is defined by the following + notation: + + dur-value = (["+"] / "-") "P" (dur-date / dur-time / dur-week) + + dur-date = dur-day [dur-time] + dur-time = "T" (dur-hour / dur-minute / dur-second) + dur-week = 1*DIGIT "W" + dur-hour = 1*DIGIT "H" [dur-minute] + dur-minute = 1*DIGIT "M" [dur-second] + dur-second = 1*DIGIT "S" + dur-day = 1*DIGIT "D" + + Description: If the property permits, multiple "duration" values are + specified by a COMMA-separated list of values. The format is + based on the [ISO.8601.2004] complete representation basic format + with designators for the duration of time. The format can + represent nominal durations (weeks and days) and accurate + durations (hours, minutes, and seconds). Note that unlike + [ISO.8601.2004], this value type doesn't support the "Y" and "M" + designators to specify durations in terms of years and months. + + + + + +Desruisseaux Standards Track [Page 35] + +RFC 5545 iCalendar September 2009 + + + The duration of a week or a day depends on its position in the + calendar. In the case of discontinuities in the time scale, such + as the change from standard time to daylight time and back, the + computation of the exact duration requires the subtraction or + addition of the change of duration of the discontinuity. Leap + seconds MUST NOT be considered when computing an exact duration. + When computing an exact duration, the greatest order time + components MUST be added first, that is, the number of days MUST + be added first, followed by the number of hours, number of + minutes, and number of seconds. + + Negative durations are typically used to schedule an alarm to + trigger before an associated time (see Section 3.8.6.3). + + No additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) are defined for this value type. + + Example: A duration of 15 days, 5 hours, and 20 seconds would be: + + P15DT5H0M20S + + A duration of 7 weeks would be: + + P7W + +3.3.7. Float + + Value Name: FLOAT + + Purpose: This value type is used to identify properties that contain + a real-number value. + + Format Definition: This value type is defined by the following + notation: + + float = (["+"] / "-") 1*DIGIT ["." 1*DIGIT] + + Description: If the property permits, multiple "float" values are + specified by a COMMA-separated list of values. + + No additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) is defined for this value type. + + Example: + + 1000000.0000001 + 1.333 + -3.14 + + + +Desruisseaux Standards Track [Page 36] + +RFC 5545 iCalendar September 2009 + + +3.3.8. Integer + + Value Name: INTEGER + + Purpose: This value type is used to identify properties that contain + a signed integer value. + + Format Definition: This value type is defined by the following + notation: + + integer = (["+"] / "-") 1*DIGIT + + Description: If the property permits, multiple "integer" values are + specified by a COMMA-separated list of values. The valid range + for "integer" is -2147483648 to 2147483647. If the sign is not + specified, then the value is assumed to be positive. + + No additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) is defined for this value type. + + Example: + + 1234567890 + -1234567890 + +1234567890 + 432109876 + +3.3.9. Period of Time + + Value Name: PERIOD + + Purpose: This value type is used to identify values that contain a + precise period of time. + + Format Definition: This value type is defined by the following + notation: + + period = period-explicit / period-start + + period-explicit = date-time "/" date-time + ; [ISO.8601.2004] complete representation basic format for a + ; period of time consisting of a start and end. The start MUST + ; be before the end. + + period-start = date-time "/" dur-value + ; [ISO.8601.2004] complete representation basic format for a + ; period of time consisting of a start and positive duration + ; of time. + + + +Desruisseaux Standards Track [Page 37] + +RFC 5545 iCalendar September 2009 + + + Description: If the property permits, multiple "period" values are + specified by a COMMA-separated list of values. There are two + forms of a period of time. First, a period of time is identified + by its start and its end. This format is based on the + [ISO.8601.2004] complete representation, basic format for "DATE- + TIME" start of the period, followed by a SOLIDUS character + followed by the "DATE-TIME" of the end of the period. The start + of the period MUST be before the end of the period. Second, a + period of time can also be defined by a start and a positive + duration of time. The format is based on the [ISO.8601.2004] + complete representation, basic format for the "DATE-TIME" start of + the period, followed by a SOLIDUS character, followed by the + [ISO.8601.2004] basic format for "DURATION" of the period. + + Example: The period starting at 18:00:00 UTC, on January 1, 1997 and + ending at 07:00:00 UTC on January 2, 1997 would be: + + 19970101T180000Z/19970102T070000Z + + The period start at 18:00:00 on January 1, 1997 and lasting 5 + hours and 30 minutes would be: + + 19970101T180000Z/PT5H30M + + No additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) is defined for this value type. + +3.3.10. Recurrence Rule + + Value Name: RECUR + + Purpose: This value type is used to identify properties that contain + a recurrence rule specification. + + Format Definition: This value type is defined by the following + notation: + + recur = recur-rule-part *( ";" recur-rule-part ) + ; + ; The rule parts are not ordered in any + ; particular sequence. + ; + ; The FREQ rule part is REQUIRED, + ; but MUST NOT occur more than once. + ; + ; The UNTIL or COUNT rule parts are OPTIONAL, + ; but they MUST NOT occur in the same 'recur'. + ; + + + +Desruisseaux Standards Track [Page 38] + +RFC 5545 iCalendar September 2009 + + + ; The other rule parts are OPTIONAL, + ; but MUST NOT occur more than once. + + recur-rule-part = ( "FREQ" "=" freq ) + / ( "UNTIL" "=" enddate ) + / ( "COUNT" "=" 1*DIGIT ) + / ( "INTERVAL" "=" 1*DIGIT ) + / ( "BYSECOND" "=" byseclist ) + / ( "BYMINUTE" "=" byminlist ) + / ( "BYHOUR" "=" byhrlist ) + / ( "BYDAY" "=" bywdaylist ) + / ( "BYMONTHDAY" "=" bymodaylist ) + / ( "BYYEARDAY" "=" byyrdaylist ) + / ( "BYWEEKNO" "=" bywknolist ) + / ( "BYMONTH" "=" bymolist ) + / ( "BYSETPOS" "=" bysplist ) + / ( "WKST" "=" weekday ) + + freq = "SECONDLY" / "MINUTELY" / "HOURLY" / "DAILY" + / "WEEKLY" / "MONTHLY" / "YEARLY" + + enddate = date / date-time + + byseclist = ( seconds *("," seconds) ) + + seconds = 1*2DIGIT ;0 to 60 + + byminlist = ( minutes *("," minutes) ) + + minutes = 1*2DIGIT ;0 to 59 + + byhrlist = ( hour *("," hour) ) + + hour = 1*2DIGIT ;0 to 23 + + bywdaylist = ( weekdaynum *("," weekdaynum) ) + + weekdaynum = [[plus / minus] ordwk] weekday + + plus = "+" + + minus = "-" + + ordwk = 1*2DIGIT ;1 to 53 + + weekday = "SU" / "MO" / "TU" / "WE" / "TH" / "FR" / "SA" + ;Corresponding to SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, + ;FRIDAY, and SATURDAY days of the week. + + + +Desruisseaux Standards Track [Page 39] + +RFC 5545 iCalendar September 2009 + + + bymodaylist = ( monthdaynum *("," monthdaynum) ) + + monthdaynum = [plus / minus] ordmoday + + ordmoday = 1*2DIGIT ;1 to 31 + + byyrdaylist = ( yeardaynum *("," yeardaynum) ) + + yeardaynum = [plus / minus] ordyrday + + ordyrday = 1*3DIGIT ;1 to 366 + + bywknolist = ( weeknum *("," weeknum) ) + + weeknum = [plus / minus] ordwk + + bymolist = ( monthnum *("," monthnum) ) + + monthnum = 1*2DIGIT ;1 to 12 + + bysplist = ( setposday *("," setposday) ) + + setposday = yeardaynum + + Description: This value type is a structured value consisting of a + list of one or more recurrence grammar parts. Each rule part is + defined by a NAME=VALUE pair. The rule parts are separated from + each other by the SEMICOLON character. The rule parts are not + ordered in any particular sequence. Individual rule parts MUST + only be specified once. Compliant applications MUST accept rule + parts ordered in any sequence, but to ensure backward + compatibility with applications that pre-date this revision of + iCalendar the FREQ rule part MUST be the first rule part specified + in a RECUR value. + + The FREQ rule part identifies the type of recurrence rule. This + rule part MUST be specified in the recurrence rule. Valid values + include SECONDLY, to specify repeating events based on an interval + of a second or more; MINUTELY, to specify repeating events based + on an interval of a minute or more; HOURLY, to specify repeating + events based on an interval of an hour or more; DAILY, to specify + repeating events based on an interval of a day or more; WEEKLY, to + specify repeating events based on an interval of a week or more; + MONTHLY, to specify repeating events based on an interval of a + month or more; and YEARLY, to specify repeating events based on an + interval of a year or more. + + + + + +Desruisseaux Standards Track [Page 40] + +RFC 5545 iCalendar September 2009 + + + The INTERVAL rule part contains a positive integer representing at + which intervals the recurrence rule repeats. The default value is + "1", meaning every second for a SECONDLY rule, every minute for a + MINUTELY rule, every hour for an HOURLY rule, every day for a + DAILY rule, every week for a WEEKLY rule, every month for a + MONTHLY rule, and every year for a YEARLY rule. For example, + within a DAILY rule, a value of "8" means every eight days. + + The UNTIL rule part defines a DATE or DATE-TIME value that bounds + the recurrence rule in an inclusive manner. If the value + specified by UNTIL is synchronized with the specified recurrence, + this DATE or DATE-TIME becomes the last instance of the + recurrence. The value of the UNTIL rule part MUST have the same + value type as the "DTSTART" property. Furthermore, if the + "DTSTART" property is specified as a date with local time, then + the UNTIL rule part MUST also be specified as a date with local + time. If the "DTSTART" property is specified as a date with UTC + time or a date with local time and time zone reference, then the + UNTIL rule part MUST be specified as a date with UTC time. In the + case of the "STANDARD" and "DAYLIGHT" sub-components the UNTIL + rule part MUST always be specified as a date with UTC time. If + specified as a DATE-TIME value, then it MUST be specified in a UTC + time format. If not present, and the COUNT rule part is also not + present, the "RRULE" is considered to repeat forever. + + The COUNT rule part defines the number of occurrences at which to + range-bound the recurrence. The "DTSTART" property value always + counts as the first occurrence. + + The BYSECOND rule part specifies a COMMA-separated list of seconds + within a minute. Valid values are 0 to 60. The BYMINUTE rule + part specifies a COMMA-separated list of minutes within an hour. + Valid values are 0 to 59. The BYHOUR rule part specifies a COMMA- + separated list of hours of the day. Valid values are 0 to 23. + The BYSECOND, BYMINUTE and BYHOUR rule parts MUST NOT be specified + when the associated "DTSTART" property has a DATE value type. + These rule parts MUST be ignored in RECUR value that violate the + above requirement (e.g., generated by applications that pre-date + this revision of iCalendar). + + The BYDAY rule part specifies a COMMA-separated list of days of + the week; SU indicates Sunday; MO indicates Monday; TU indicates + Tuesday; WE indicates Wednesday; TH indicates Thursday; FR + indicates Friday; and SA indicates Saturday. + + Each BYDAY value can also be preceded by a positive (+n) or + negative (-n) integer. If present, this indicates the nth + occurrence of a specific day within the MONTHLY or YEARLY "RRULE". + + + +Desruisseaux Standards Track [Page 41] + +RFC 5545 iCalendar September 2009 + + + For example, within a MONTHLY rule, +1MO (or simply 1MO) + represents the first Monday within the month, whereas -1MO + represents the last Monday of the month. The numeric value in a + BYDAY rule part with the FREQ rule part set to YEARLY corresponds + to an offset within the month when the BYMONTH rule part is + present, and corresponds to an offset within the year when the + BYWEEKNO or BYMONTH rule parts are present. If an integer + modifier is not present, it means all days of this type within the + specified frequency. For example, within a MONTHLY rule, MO + represents all Mondays within the month. The BYDAY rule part MUST + NOT be specified with a numeric value when the FREQ rule part is + not set to MONTHLY or YEARLY. Furthermore, the BYDAY rule part + MUST NOT be specified with a numeric value with the FREQ rule part + set to YEARLY when the BYWEEKNO rule part is specified. + + The BYMONTHDAY rule part specifies a COMMA-separated list of days + of the month. Valid values are 1 to 31 or -31 to -1. For + example, -10 represents the tenth to the last day of the month. + The BYMONTHDAY rule part MUST NOT be specified when the FREQ rule + part is set to WEEKLY. + + The BYYEARDAY rule part specifies a COMMA-separated list of days + of the year. Valid values are 1 to 366 or -366 to -1. For + example, -1 represents the last day of the year (December 31st) + and -306 represents the 306th to the last day of the year (March + 1st). The BYYEARDAY rule part MUST NOT be specified when the FREQ + rule part is set to DAILY, WEEKLY, or MONTHLY. + + The BYWEEKNO rule part specifies a COMMA-separated list of + ordinals specifying weeks of the year. Valid values are 1 to 53 + or -53 to -1. This corresponds to weeks according to week + numbering as defined in [ISO.8601.2004]. A week is defined as a + seven day period, starting on the day of the week defined to be + the week start (see WKST). Week number one of the calendar year + is the first week that contains at least four (4) days in that + calendar year. This rule part MUST NOT be used when the FREQ rule + part is set to anything other than YEARLY. For example, 3 + represents the third week of the year. + + Note: Assuming a Monday week start, week 53 can only occur when + Thursday is January 1 or if it is a leap year and Wednesday is + January 1. + + The BYMONTH rule part specifies a COMMA-separated list of months + of the year. Valid values are 1 to 12. + + The WKST rule part specifies the day on which the workweek starts. + Valid values are MO, TU, WE, TH, FR, SA, and SU. This is + + + +Desruisseaux Standards Track [Page 42] + +RFC 5545 iCalendar September 2009 + + + significant when a WEEKLY "RRULE" has an interval greater than 1, + and a BYDAY rule part is specified. This is also significant when + in a YEARLY "RRULE" when a BYWEEKNO rule part is specified. The + default value is MO. + + The BYSETPOS rule part specifies a COMMA-separated list of values + that corresponds to the nth occurrence within the set of + recurrence instances specified by the rule. BYSETPOS operates on + a set of recurrence instances in one interval of the recurrence + rule. For example, in a WEEKLY rule, the interval would be one + week A set of recurrence instances starts at the beginning of the + interval defined by the FREQ rule part. Valid values are 1 to 366 + or -366 to -1. It MUST only be used in conjunction with another + BYxxx rule part. For example "the last work day of the month" + could be represented as: + + FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-1 + + Each BYSETPOS value can include a positive (+n) or negative (-n) + integer. If present, this indicates the nth occurrence of the + specific occurrence within the set of occurrences specified by the + rule. + + Recurrence rules may generate recurrence instances with an invalid + date (e.g., February 30) or nonexistent local time (e.g., 1:30 AM + on a day where the local time is moved forward by an hour at 1:00 + AM). Such recurrence instances MUST be ignored and MUST NOT be + counted as part of the recurrence set. + + Information, not contained in the rule, necessary to determine the + various recurrence instance start time and dates are derived from + the Start Time ("DTSTART") component attribute. For example, + "FREQ=YEARLY;BYMONTH=1" doesn't specify a specific day within the + month or a time. This information would be the same as what is + specified for "DTSTART". + + BYxxx rule parts modify the recurrence in some manner. BYxxx rule + parts for a period of time that is the same or greater than the + frequency generally reduce or limit the number of occurrences of + the recurrence generated. For example, "FREQ=DAILY;BYMONTH=1" + reduces the number of recurrence instances from all days (if + BYMONTH rule part is not present) to all days in January. BYxxx + rule parts for a period of time less than the frequency generally + increase or expand the number of occurrences of the recurrence. + For example, "FREQ=YEARLY;BYMONTH=1,2" increases the number of + days within the yearly recurrence set from 1 (if BYMONTH rule part + is not present) to 2. + + + + +Desruisseaux Standards Track [Page 43] + +RFC 5545 iCalendar September 2009 + + + If multiple BYxxx rule parts are specified, then after evaluating + the specified FREQ and INTERVAL rule parts, the BYxxx rule parts + are applied to the current set of evaluated occurrences in the + following order: BYMONTH, BYWEEKNO, BYYEARDAY, BYMONTHDAY, BYDAY, + BYHOUR, BYMINUTE, BYSECOND and BYSETPOS; then COUNT and UNTIL are + evaluated. + + The table below summarizes the dependency of BYxxx rule part + expand or limit behavior on the FREQ rule part value. + + The term "N/A" means that the corresponding BYxxx rule part MUST + NOT be used with the corresponding FREQ value. + + BYDAY has some special behavior depending on the FREQ value and + this is described in separate notes below the table. + + +----------+--------+--------+-------+-------+------+-------+------+ + | |SECONDLY|MINUTELY|HOURLY |DAILY |WEEKLY|MONTHLY|YEARLY| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYMONTH |Limit |Limit |Limit |Limit |Limit |Limit |Expand| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYWEEKNO |N/A |N/A |N/A |N/A |N/A |N/A |Expand| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYYEARDAY |Limit |Limit |Limit |N/A |N/A |N/A |Expand| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYMONTHDAY|Limit |Limit |Limit |Limit |N/A |Expand |Expand| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYDAY |Limit |Limit |Limit |Limit |Expand|Note 1 |Note 2| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYHOUR |Limit |Limit |Limit |Expand |Expand|Expand |Expand| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYMINUTE |Limit |Limit |Expand |Expand |Expand|Expand |Expand| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYSECOND |Limit |Expand |Expand |Expand |Expand|Expand |Expand| + +----------+--------+--------+-------+-------+------+-------+------+ + |BYSETPOS |Limit |Limit |Limit |Limit |Limit |Limit |Limit | + +----------+--------+--------+-------+-------+------+-------+------+ + + Note 1: Limit if BYMONTHDAY is present; otherwise, special expand + for MONTHLY. + + Note 2: Limit if BYYEARDAY or BYMONTHDAY is present; otherwise, + special expand for WEEKLY if BYWEEKNO present; otherwise, + special expand for MONTHLY if BYMONTH present; otherwise, + special expand for YEARLY. + + + + + + +Desruisseaux Standards Track [Page 44] + +RFC 5545 iCalendar September 2009 + + + Here is an example of evaluating multiple BYxxx rule parts. + + DTSTART;TZID=America/New_York:19970105T083000 + RRULE:FREQ=YEARLY;INTERVAL=2;BYMONTH=1;BYDAY=SU;BYHOUR=8,9; + BYMINUTE=30 + + First, the "INTERVAL=2" would be applied to "FREQ=YEARLY" to + arrive at "every other year". Then, "BYMONTH=1" would be applied + to arrive at "every January, every other year". Then, "BYDAY=SU" + would be applied to arrive at "every Sunday in January, every + other year". Then, "BYHOUR=8,9" would be applied to arrive at + "every Sunday in January at 8 AM and 9 AM, every other year". + Then, "BYMINUTE=30" would be applied to arrive at "every Sunday in + January at 8:30 AM and 9:30 AM, every other year". Then, lacking + information from "RRULE", the second is derived from "DTSTART", to + end up in "every Sunday in January at 8:30:00 AM and 9:30:00 AM, + every other year". Similarly, if the BYMINUTE, BYHOUR, BYDAY, + BYMONTHDAY, or BYMONTH rule part were missing, the appropriate + minute, hour, day, or month would have been retrieved from the + "DTSTART" property. + + If the computed local start time of a recurrence instance does not + exist, or occurs more than once, for the specified time zone, the + time of the recurrence instance is interpreted in the same manner + as an explicit DATE-TIME value describing that date and time, as + specified in Section 3.3.5. + + No additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) is defined for this value type. + + Example: The following is a rule that specifies 10 occurrences that + occur every other day: + + FREQ=DAILY;COUNT=10;INTERVAL=2 + + There are other examples specified in Section 3.8.5.3. + +3.3.11. Text + + Value Name: TEXT + + Purpose: This value type is used to identify values that contain + human-readable text. + + Format Definition: This value type is defined by the following + notation: + + + + + +Desruisseaux Standards Track [Page 45] + +RFC 5545 iCalendar September 2009 + + + text = *(TSAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR) + ; Folded according to description above + + ESCAPED-CHAR = ("\\" / "\;" / "\," / "\N" / "\n") + ; \\ encodes \, \N or \n encodes newline + ; \; encodes ;, \, encodes , + + TSAFE-CHAR = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-5B / + %x5D-7E / NON-US-ASCII + ; Any character except CONTROLs not needed by the current + ; character set, DQUOTE, ";", ":", "\", "," + + Description: If the property permits, multiple TEXT values are + specified by a COMMA-separated list of values. + + The language in which the text is represented can be controlled by + the "LANGUAGE" property parameter. + + An intentional formatted text line break MUST only be included in + a "TEXT" property value by representing the line break with the + character sequence of BACKSLASH, followed by a LATIN SMALL LETTER + N or a LATIN CAPITAL LETTER N, that is "\n" or "\N". + + The "TEXT" property values may also contain special characters + that are used to signify delimiters, such as a COMMA character for + lists of values or a SEMICOLON character for structured values. + In order to support the inclusion of these special characters in + "TEXT" property values, they MUST be escaped with a BACKSLASH + character. A BACKSLASH character in a "TEXT" property value MUST + be escaped with another BACKSLASH character. A COMMA character in + a "TEXT" property value MUST be escaped with a BACKSLASH + character. A SEMICOLON character in a "TEXT" property value MUST + be escaped with a BACKSLASH character. However, a COLON character + in a "TEXT" property value SHALL NOT be escaped with a BACKSLASH + character. + + Example: A multiple line value of: + + Project XYZ Final Review + Conference Room - 3B + Come Prepared. + + would be represented as: + + Project XYZ Final Review\nConference Room - 3B\nCome Prepared. + + + + + + +Desruisseaux Standards Track [Page 46] + +RFC 5545 iCalendar September 2009 + + +3.3.12. Time + + Value Name: TIME + + Purpose: This value type is used to identify values that contain a + time of day. + + Format Definition: This value type is defined by the following + notation: + + time = time-hour time-minute time-second [time-utc] + + time-hour = 2DIGIT ;00-23 + time-minute = 2DIGIT ;00-59 + time-second = 2DIGIT ;00-60 + ;The "60" value is used to account for positive "leap" seconds. + + time-utc = "Z" + + Description: If the property permits, multiple "time" values are + specified by a COMMA-separated list of values. No additional + content value encoding (i.e., BACKSLASH character encoding, see + Section 3.3.11) is defined for this value type. + + The "TIME" value type is used to identify values that contain a + time of day. The format is based on the [ISO.8601.2004] complete + representation, basic format for a time of day. The text format + consists of a two-digit, 24-hour of the day (i.e., values 00-23), + two-digit minute in the hour (i.e., values 00-59), and two-digit + seconds in the minute (i.e., values 00-60). The seconds value of + 60 MUST only be used to account for positive "leap" seconds. + Fractions of a second are not supported by this format. + + In parallel to the "DATE-TIME" definition above, the "TIME" value + type expresses time values in three forms: + + The form of time with UTC offset MUST NOT be used. For example, + the following is not valid for a time value: + + 230000-0800 ;Invalid time format + + FORM #1 LOCAL TIME + + The local time form is simply a time value that does not contain + the UTC designator nor does it reference a time zone. For + example, 11:00 PM: + + 230000 + + + +Desruisseaux Standards Track [Page 47] + +RFC 5545 iCalendar September 2009 + + + Time values of this type are said to be "floating" and are not + bound to any time zone in particular. They are used to represent + the same hour, minute, and second value regardless of which time + zone is currently being observed. For example, an event can be + defined that indicates that an individual will be busy from 11:00 + AM to 1:00 PM every day, no matter which time zone the person is + in. In these cases, a local time can be specified. The recipient + of an iCalendar object with a property value consisting of a local + time, without any relative time zone information, SHOULD interpret + the value as being fixed to whatever time zone the "ATTENDEE" is + in at any given moment. This means that two "Attendees", may + participate in the same event at different UTC times; floating + time SHOULD only be used where that is reasonable behavior. + + In most cases, a fixed time is desired. To properly communicate a + fixed time in a property value, either UTC time or local time with + time zone reference MUST be specified. + + The use of local time in a TIME value without the "TZID" property + parameter is to be interpreted as floating time, regardless of the + existence of "VTIMEZONE" calendar components in the iCalendar + object. + + FORM #2: UTC TIME + + UTC time, or absolute time, is identified by a LATIN CAPITAL + LETTER Z suffix character, the UTC designator, appended to the + time value. For example, the following represents 07:00 AM UTC: + + 070000Z + + The "TZID" property parameter MUST NOT be applied to TIME + properties whose time values are specified in UTC. + + FORM #3: LOCAL TIME AND TIME ZONE REFERENCE + + The local time with reference to time zone information form is + identified by the use the "TZID" property parameter to reference + the appropriate time zone definition. "TZID" is discussed in + detail in Section 3.2.19. + + Example: The following represents 8:30 AM in New York in winter, + five hours behind UTC, in each of the three formats: + + 083000 + 133000Z + TZID=America/New_York:083000 + + + + +Desruisseaux Standards Track [Page 48] + +RFC 5545 iCalendar September 2009 + + +3.3.13. URI + + Value Name: URI + + Purpose: This value type is used to identify values that contain a + uniform resource identifier (URI) type of reference to the + property value. + + Format Definition: This value type is defined by the following + notation: + + uri = + + Description: This value type might be used to reference binary + information, for values that are large, or otherwise undesirable + to include directly in the iCalendar object. + + Property values with this value type MUST follow the generic URI + syntax defined in [RFC3986]. + + When a property parameter value is a URI value type, the URI MUST + be specified as a quoted-string value. + + No additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) is defined for this value type. + + Example: The following is a URI for a network file: + + http://example.com/my-report.txt + +3.3.14. UTC Offset + + Value Name: UTC-OFFSET + + Purpose: This value type is used to identify properties that contain + an offset from UTC to local time. + + Format Definition: This value type is defined by the following + notation: + + utc-offset = time-numzone + + time-numzone = ("+" / "-") time-hour time-minute [time-second] + + Description: The PLUS SIGN character MUST be specified for positive + UTC offsets (i.e., ahead of UTC). The HYPHEN-MINUS character MUST + be specified for negative UTC offsets (i.e., behind of UTC). The + + + + +Desruisseaux Standards Track [Page 49] + +RFC 5545 iCalendar September 2009 + + + value of "-0000" and "-000000" are not allowed. The time-second, + if present, MUST NOT be 60; if absent, it defaults to zero. + + No additional content value encoding (i.e., BACKSLASH character + encoding, see Section 3.3.11) is defined for this value type. + + Example: The following UTC offsets are given for standard time for + New York (five hours behind UTC) and Geneva (one hour ahead of + UTC): + + -0500 + + +0100 + +3.4. iCalendar Object + + The Calendaring and Scheduling Core Object is a collection of + calendaring and scheduling information. Typically, this information + will consist of an iCalendar stream with a single iCalendar object. + However, multiple iCalendar objects can be sequentially grouped + together in an iCalendar stream. The first line and last line of the + iCalendar object MUST contain a pair of iCalendar object delimiter + strings. The syntax for an iCalendar stream is as follows: + + icalstream = 1*icalobject + + icalobject = "BEGIN" ":" "VCALENDAR" CRLF + icalbody + "END" ":" "VCALENDAR" CRLF + + The following is a simple example of an iCalendar object: + + BEGIN:VCALENDAR + VERSION:2.0 + PRODID:-//hacksw/handcal//NONSGML v1.0//EN + BEGIN:VEVENT + UID:19970610T172345Z-AF23B2@example.com + DTSTAMP:19970610T172345Z + DTSTART:19970714T170000Z + DTEND:19970715T040000Z + SUMMARY:Bastille Day Party + END:VEVENT + END:VCALENDAR + + + + + + + + +Desruisseaux Standards Track [Page 50] + +RFC 5545 iCalendar September 2009 + + +3.5. Property + + A property is the definition of an individual attribute describing a + calendar object or a calendar component. A property takes the form + defined by the "contentline" notation defined in Section 3.1. + + The following is an example of a property: + + DTSTART:19960415T133000Z + + This memo imposes no ordering of properties within an iCalendar + object. + + Property names, parameter names, and enumerated parameter values are + case-insensitive. For example, the property name "DUE" is the same + as "due" and "Due", DTSTART;TZID=America/New_York:19980714T120000 is + the same as DtStart;TzID=America/New_York:19980714T120000. + +3.6. Calendar Components + + The body of the iCalendar object consists of a sequence of calendar + properties and one or more calendar components. The calendar + properties are attributes that apply to the calendar object as a + whole. The calendar components are collections of properties that + express a particular calendar semantic. For example, the calendar + component can specify an event, a to-do, a journal entry, time zone + information, free/busy time information, or an alarm. + + The body of the iCalendar object is defined by the following + notation: + + icalbody = calprops component + + calprops = *( + ; + ; The following are REQUIRED, + ; but MUST NOT occur more than once. + ; + prodid / version / + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + calscale / method / + ; + ; The following are OPTIONAL, + ; and MAY occur more than once. + ; + + + +Desruisseaux Standards Track [Page 51] + +RFC 5545 iCalendar September 2009 + + + x-prop / iana-prop + ; + ) + + component = 1*(eventc / todoc / journalc / freebusyc / + timezonec / iana-comp / x-comp) + + iana-comp = "BEGIN" ":" iana-token CRLF + 1*contentline + "END" ":" iana-token CRLF + + x-comp = "BEGIN" ":" x-name CRLF + 1*contentline + "END" ":" x-name CRLF + + An iCalendar object MUST include the "PRODID" and "VERSION" calendar + properties. In addition, it MUST include at least one calendar + component. Special forms of iCalendar objects are possible to + publish just busy time (i.e., only a "VFREEBUSY" calendar component) + or time zone (i.e., only a "VTIMEZONE" calendar component) + information. In addition, a complex iCalendar object that is used to + capture a complete snapshot of the contents of a calendar is possible + (e.g., composite of many different calendar components). More + commonly, an iCalendar object will consist of just a single "VEVENT", + "VTODO", or "VJOURNAL" calendar component. Applications MUST ignore + x-comp and iana-comp values they don't recognize. Applications that + support importing iCalendar objects SHOULD support all of the + component types defined in this document, and SHOULD NOT silently + drop any components as that can lead to user data loss. + +3.6.1. Event Component + + Component Name: VEVENT + + Purpose: Provide a grouping of component properties that describe an + event. + + Format Definition: A "VEVENT" calendar component is defined by the + following notation: + + eventc = "BEGIN" ":" "VEVENT" CRLF + eventprop *alarmc + "END" ":" "VEVENT" CRLF + + eventprop = *( + ; + ; The following are REQUIRED, + ; but MUST NOT occur more than once. + + + +Desruisseaux Standards Track [Page 52] + +RFC 5545 iCalendar September 2009 + + + ; + dtstamp / uid / + ; + ; The following is REQUIRED if the component + ; appears in an iCalendar object that doesn't + ; specify the "METHOD" property; otherwise, it + ; is OPTIONAL; in any case, it MUST NOT occur + ; more than once. + ; + dtstart / + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + class / created / description / geo / + last-mod / location / organizer / priority / + seq / status / summary / transp / + url / recurid / + ; + ; The following is OPTIONAL, + ; but SHOULD NOT occur more than once. + ; + rrule / + ; + ; Either 'dtend' or 'duration' MAY appear in + ; a 'eventprop', but 'dtend' and 'duration' + ; MUST NOT occur in the same 'eventprop'. + ; + dtend / duration / + ; + ; The following are OPTIONAL, + ; and MAY occur more than once. + ; + attach / attendee / categories / comment / + contact / exdate / rstatus / related / + resources / rdate / x-prop / iana-prop + ; + ) + + Description: A "VEVENT" calendar component is a grouping of + component properties, possibly including "VALARM" calendar + components, that represents a scheduled amount of time on a + calendar. For example, it can be an activity; such as a one-hour + long, department meeting from 8:00 AM to 9:00 AM, tomorrow. + Generally, an event will take up time on an individual calendar. + Hence, the event will appear as an opaque interval in a search for + busy time. Alternately, the event can have its Time Transparency + + + + +Desruisseaux Standards Track [Page 53] + +RFC 5545 iCalendar September 2009 + + + set to "TRANSPARENT" in order to prevent blocking of the event in + searches for busy time. + + The "VEVENT" is also the calendar component used to specify an + anniversary or daily reminder within a calendar. These events + have a DATE value type for the "DTSTART" property instead of the + default value type of DATE-TIME. If such a "VEVENT" has a "DTEND" + property, it MUST be specified as a DATE value also. The + anniversary type of "VEVENT" can span more than one date (i.e., + "DTEND" property value is set to a calendar date after the + "DTSTART" property value). If such a "VEVENT" has a "DURATION" + property, it MUST be specified as a "dur-day" or "dur-week" value. + + The "DTSTART" property for a "VEVENT" specifies the inclusive + start of the event. For recurring events, it also specifies the + very first instance in the recurrence set. The "DTEND" property + for a "VEVENT" calendar component specifies the non-inclusive end + of the event. For cases where a "VEVENT" calendar component + specifies a "DTSTART" property with a DATE value type but no + "DTEND" nor "DURATION" property, the event's duration is taken to + be one day. For cases where a "VEVENT" calendar component + specifies a "DTSTART" property with a DATE-TIME value type but no + "DTEND" property, the event ends on the same calendar date and + time of day specified by the "DTSTART" property. + + The "VEVENT" calendar component cannot be nested within another + calendar component. However, "VEVENT" calendar components can be + related to each other or to a "VTODO" or to a "VJOURNAL" calendar + component with the "RELATED-TO" property. + + Example: The following is an example of the "VEVENT" calendar + component used to represent a meeting that will also be opaque to + searches for busy time: + + BEGIN:VEVENT + UID:19970901T130000Z-123401@example.com + DTSTAMP:19970901T130000Z + DTSTART:19970903T163000Z + DTEND:19970903T190000Z + SUMMARY:Annual Employee Review + CLASS:PRIVATE + CATEGORIES:BUSINESS,HUMAN RESOURCES + END:VEVENT + + The following is an example of the "VEVENT" calendar component + used to represent a reminder that will not be opaque, but rather + transparent, to searches for busy time: + + + + +Desruisseaux Standards Track [Page 54] + +RFC 5545 iCalendar September 2009 + + + BEGIN:VEVENT + UID:19970901T130000Z-123402@example.com + DTSTAMP:19970901T130000Z + DTSTART:19970401T163000Z + DTEND:19970402T010000Z + SUMMARY:Laurel is in sensitivity awareness class. + CLASS:PUBLIC + CATEGORIES:BUSINESS,HUMAN RESOURCES + TRANSP:TRANSPARENT + END:VEVENT + + The following is an example of the "VEVENT" calendar component + used to represent an anniversary that will occur annually: + + BEGIN:VEVENT + UID:19970901T130000Z-123403@example.com + DTSTAMP:19970901T130000Z + DTSTART;VALUE=DATE:19971102 + SUMMARY:Our Blissful Anniversary + TRANSP:TRANSPARENT + CLASS:CONFIDENTIAL + CATEGORIES:ANNIVERSARY,PERSONAL,SPECIAL OCCASION + RRULE:FREQ=YEARLY + END:VEVENT + + The following is an example of the "VEVENT" calendar component + used to represent a multi-day event scheduled from June 28th, 2007 + to July 8th, 2007 inclusively. Note that the "DTEND" property is + set to July 9th, 2007, since the "DTEND" property specifies the + non-inclusive end of the event. + + BEGIN:VEVENT + UID:20070423T123432Z-541111@example.com + DTSTAMP:20070423T123432Z + DTSTART;VALUE=DATE:20070628 + DTEND;VALUE=DATE:20070709 + SUMMARY:Festival International de Jazz de Montreal + TRANSP:TRANSPARENT + END:VEVENT + +3.6.2. To-Do Component + + Component Name: VTODO + + Purpose: Provide a grouping of calendar properties that describe a + to-do. + + + + + +Desruisseaux Standards Track [Page 55] + +RFC 5545 iCalendar September 2009 + + + Format Definition: A "VTODO" calendar component is defined by the + following notation: + + todoc = "BEGIN" ":" "VTODO" CRLF + todoprop *alarmc + "END" ":" "VTODO" CRLF + + todoprop = *( + ; + ; The following are REQUIRED, + ; but MUST NOT occur more than once. + ; + dtstamp / uid / + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + class / completed / created / description / + dtstart / geo / last-mod / location / organizer / + percent / priority / recurid / seq / status / + summary / url / + ; + ; The following is OPTIONAL, + ; but SHOULD NOT occur more than once. + ; + rrule / + ; + ; Either 'due' or 'duration' MAY appear in + ; a 'todoprop', but 'due' and 'duration' + ; MUST NOT occur in the same 'todoprop'. + ; If 'duration' appear in a 'todoprop', + ; then 'dtstart' MUST also appear in + ; the same 'todoprop'. + ; + due / duration / + ; + ; The following are OPTIONAL, + ; and MAY occur more than once. + ; + attach / attendee / categories / comment / contact / + exdate / rstatus / related / resources / + rdate / x-prop / iana-prop + ; + ) + + Description: A "VTODO" calendar component is a grouping of component + properties and possibly "VALARM" calendar components that + represent an action-item or assignment. For example, it can be + + + +Desruisseaux Standards Track [Page 56] + +RFC 5545 iCalendar September 2009 + + + used to represent an item of work assigned to an individual; such + as "turn in travel expense today". + + The "VTODO" calendar component cannot be nested within another + calendar component. However, "VTODO" calendar components can be + related to each other or to a "VEVENT" or to a "VJOURNAL" calendar + component with the "RELATED-TO" property. + + A "VTODO" calendar component without the "DTSTART" and "DUE" (or + "DURATION") properties specifies a to-do that will be associated + with each successive calendar date, until it is completed. + + Examples: The following is an example of a "VTODO" calendar + component that needs to be completed before May 1st, 2007. On + midnight May 1st, 2007 this to-do would be considered overdue. + + BEGIN:VTODO + UID:20070313T123432Z-456553@example.com + DTSTAMP:20070313T123432Z + DUE;VALUE=DATE:20070501 + SUMMARY:Submit Quebec Income Tax Return for 2006 + CLASS:CONFIDENTIAL + CATEGORIES:FAMILY,FINANCE + STATUS:NEEDS-ACTION + END:VTODO + + The following is an example of a "VTODO" calendar component that + was due before 1:00 P.M. UTC on July 9th, 2007 and was completed + on July 7th, 2007 at 10:00 A.M. UTC. + + BEGIN:VTODO + UID:20070514T103211Z-123404@example.com + DTSTAMP:20070514T103211Z + DTSTART:20070514T110000Z + DUE:20070709T130000Z + COMPLETED:20070707T100000Z + SUMMARY:Submit Revised Internet-Draft + PRIORITY:1 + STATUS:NEEDS-ACTION + END:VTODO + +3.6.3. Journal Component + + Component Name: VJOURNAL + + Purpose: Provide a grouping of component properties that describe a + journal entry. + + + + +Desruisseaux Standards Track [Page 57] + +RFC 5545 iCalendar September 2009 + + + Format Definition: A "VJOURNAL" calendar component is defined by the + following notation: + + journalc = "BEGIN" ":" "VJOURNAL" CRLF + jourprop + "END" ":" "VJOURNAL" CRLF + + jourprop = *( + ; + ; The following are REQUIRED, + ; but MUST NOT occur more than once. + ; + dtstamp / uid / + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + class / created / dtstart / + last-mod / organizer / recurid / seq / + status / summary / url / + ; + ; The following is OPTIONAL, + ; but SHOULD NOT occur more than once. + ; + rrule / + ; + ; The following are OPTIONAL, + ; and MAY occur more than once. + ; + attach / attendee / categories / comment / + contact / description / exdate / related / rdate / + rstatus / x-prop / iana-prop + ; + ) + + Description: A "VJOURNAL" calendar component is a grouping of + component properties that represent one or more descriptive text + notes associated with a particular calendar date. The "DTSTART" + property is used to specify the calendar date with which the + journal entry is associated. Generally, it will have a DATE value + data type, but it can also be used to specify a DATE-TIME value + data type. Examples of a journal entry include a daily record of + a legislative body or a journal entry of individual telephone + contacts for the day or an ordered list of accomplishments for the + day. The "VJOURNAL" calendar component can also be used to + associate a document with a calendar date. + + + + + +Desruisseaux Standards Track [Page 58] + +RFC 5545 iCalendar September 2009 + + + The "VJOURNAL" calendar component does not take up time on a + calendar. Hence, it does not play a role in free or busy time + searches -- it is as though it has a time transparency value of + TRANSPARENT. It is transparent to any such searches. + + The "VJOURNAL" calendar component cannot be nested within another + calendar component. However, "VJOURNAL" calendar components can + be related to each other or to a "VEVENT" or to a "VTODO" calendar + component, with the "RELATED-TO" property. + + Example: The following is an example of the "VJOURNAL" calendar + component: + + BEGIN:VJOURNAL + UID:19970901T130000Z-123405@example.com + DTSTAMP:19970901T130000Z + DTSTART;VALUE=DATE:19970317 + SUMMARY:Staff meeting minutes + DESCRIPTION:1. Staff meeting: Participants include Joe\, + Lisa\, and Bob. Aurora project plans were reviewed. + There is currently no budget reserves for this project. + Lisa will escalate to management. Next meeting on Tuesday.\n + 2. Telephone Conference: ABC Corp. sales representative + called to discuss new printer. Promised to get us a demo by + Friday.\n3. Henry Miller (Handsoff Insurance): Car was + totaled by tree. Is looking into a loaner car. 555-2323 + (tel). + END:VJOURNAL + +3.6.4. Free/Busy Component + + Component Name: VFREEBUSY + + Purpose: Provide a grouping of component properties that describe + either a request for free/busy time, describe a response to a + request for free/busy time, or describe a published set of busy + time. + + Format Definition: A "VFREEBUSY" calendar component is defined by + the following notation: + + freebusyc = "BEGIN" ":" "VFREEBUSY" CRLF + fbprop + "END" ":" "VFREEBUSY" CRLF + + fbprop = *( + ; + ; The following are REQUIRED, + + + +Desruisseaux Standards Track [Page 59] + +RFC 5545 iCalendar September 2009 + + + ; but MUST NOT occur more than once. + ; + dtstamp / uid / + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + contact / dtstart / dtend / + organizer / url / + ; + ; The following are OPTIONAL, + ; and MAY occur more than once. + ; + attendee / comment / freebusy / rstatus / x-prop / + iana-prop + ; + ) + + Description: A "VFREEBUSY" calendar component is a grouping of + component properties that represents either a request for free or + busy time information, a reply to a request for free or busy time + information, or a published set of busy time information. + + When used to request free/busy time information, the "ATTENDEE" + property specifies the calendar users whose free/busy time is + being requested; the "ORGANIZER" property specifies the calendar + user who is requesting the free/busy time; the "DTSTART" and + "DTEND" properties specify the window of time for which the free/ + busy time is being requested; the "UID" and "DTSTAMP" properties + are specified to assist in proper sequencing of multiple free/busy + time requests. + + When used to reply to a request for free/busy time, the "ATTENDEE" + property specifies the calendar user responding to the free/busy + time request; the "ORGANIZER" property specifies the calendar user + that originally requested the free/busy time; the "FREEBUSY" + property specifies the free/busy time information (if it exists); + and the "UID" and "DTSTAMP" properties are specified to assist in + proper sequencing of multiple free/busy time replies. + + When used to publish busy time, the "ORGANIZER" property specifies + the calendar user associated with the published busy time; the + "DTSTART" and "DTEND" properties specify an inclusive time window + that surrounds the busy time information; the "FREEBUSY" property + specifies the published busy time information; and the "DTSTAMP" + property specifies the DATE-TIME that iCalendar object was + created. + + + + +Desruisseaux Standards Track [Page 60] + +RFC 5545 iCalendar September 2009 + + + The "VFREEBUSY" calendar component cannot be nested within another + calendar component. Multiple "VFREEBUSY" calendar components can + be specified within an iCalendar object. This permits the + grouping of free/busy information into logical collections, such + as monthly groups of busy time information. + + The "VFREEBUSY" calendar component is intended for use in + iCalendar object methods involving requests for free time, + requests for busy time, requests for both free and busy, and the + associated replies. + + Free/Busy information is represented with the "FREEBUSY" property. + This property provides a terse representation of time periods. + One or more "FREEBUSY" properties can be specified in the + "VFREEBUSY" calendar component. + + When present in a "VFREEBUSY" calendar component, the "DTSTART" + and "DTEND" properties SHOULD be specified prior to any "FREEBUSY" + properties. + + The recurrence properties ("RRULE", "RDATE", "EXDATE") are not + permitted within a "VFREEBUSY" calendar component. Any recurring + events are resolved into their individual busy time periods using + the "FREEBUSY" property. + + Example: The following is an example of a "VFREEBUSY" calendar + component used to request free or busy time information: + + BEGIN:VFREEBUSY + UID:19970901T082949Z-FA43EF@example.com + ORGANIZER:mailto:jane_doe@example.com + ATTENDEE:mailto:john_public@example.com + DTSTART:19971015T050000Z + DTEND:19971016T050000Z + DTSTAMP:19970901T083000Z + END:VFREEBUSY + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 61] + +RFC 5545 iCalendar September 2009 + + + The following is an example of a "VFREEBUSY" calendar component + used to reply to the request with busy time information: + + BEGIN:VFREEBUSY + UID:19970901T095957Z-76A912@example.com + ORGANIZER:mailto:jane_doe@example.com + ATTENDEE:mailto:john_public@example.com + DTSTAMP:19970901T100000Z + FREEBUSY:19971015T050000Z/PT8H30M, + 19971015T160000Z/PT5H30M,19971015T223000Z/PT6H30M + URL:http://example.com/pub/busy/jpublic-01.ifb + COMMENT:This iCalendar file contains busy time information for + the next three months. + END:VFREEBUSY + + The following is an example of a "VFREEBUSY" calendar component + used to publish busy time information: + + BEGIN:VFREEBUSY + UID:19970901T115957Z-76A912@example.com + DTSTAMP:19970901T120000Z + ORGANIZER:jsmith@example.com + DTSTART:19980313T141711Z + DTEND:19980410T141711Z + FREEBUSY:19980314T233000Z/19980315T003000Z + FREEBUSY:19980316T153000Z/19980316T163000Z + FREEBUSY:19980318T030000Z/19980318T040000Z + URL:http://www.example.com/calendar/busytime/jsmith.ifb + END:VFREEBUSY + +3.6.5. Time Zone Component + + Component Name: VTIMEZONE + + Purpose: Provide a grouping of component properties that defines a + time zone. + + Format Definition: A "VTIMEZONE" calendar component is defined by + the following notation: + + timezonec = "BEGIN" ":" "VTIMEZONE" CRLF + *( + ; + ; 'tzid' is REQUIRED, but MUST NOT occur more + ; than once. + ; + tzid / + ; + + + +Desruisseaux Standards Track [Page 62] + +RFC 5545 iCalendar September 2009 + + + ; 'last-mod' and 'tzurl' are OPTIONAL, + ; but MUST NOT occur more than once. + ; + last-mod / tzurl / + ; + ; One of 'standardc' or 'daylightc' MUST occur + ; and each MAY occur more than once. + ; + standardc / daylightc / + ; + ; The following are OPTIONAL, + ; and MAY occur more than once. + ; + x-prop / iana-prop + ; + ) + "END" ":" "VTIMEZONE" CRLF + + standardc = "BEGIN" ":" "STANDARD" CRLF + tzprop + "END" ":" "STANDARD" CRLF + + daylightc = "BEGIN" ":" "DAYLIGHT" CRLF + tzprop + "END" ":" "DAYLIGHT" CRLF + + tzprop = *( + ; + ; The following are REQUIRED, + ; but MUST NOT occur more than once. + ; + dtstart / tzoffsetto / tzoffsetfrom / + ; + ; The following is OPTIONAL, + ; but SHOULD NOT occur more than once. + ; + rrule / + ; + ; The following are OPTIONAL, + ; and MAY occur more than once. + ; + comment / rdate / tzname / x-prop / iana-prop + ; + ) + + Description: A time zone is unambiguously defined by the set of time + measurement rules determined by the governing body for a given + geographic area. These rules describe, at a minimum, the base + + + +Desruisseaux Standards Track [Page 63] + +RFC 5545 iCalendar September 2009 + + + offset from UTC for the time zone, often referred to as the + Standard Time offset. Many locations adjust their Standard Time + forward or backward by one hour, in order to accommodate seasonal + changes in number of daylight hours, often referred to as Daylight + Saving Time. Some locations adjust their time by a fraction of an + hour. Standard Time is also known as Winter Time. Daylight + Saving Time is also known as Advanced Time, Summer Time, or Legal + Time in certain countries. The following table shows the changes + in time zone rules in effect for New York City starting from 1967. + Each line represents a description or rule for a particular + observance. + + Effective Observance Rule + + +-----------+--------------------------+--------+--------------+ + | Date | (Date-Time) | Offset | Abbreviation | + +-----------+--------------------------+--------+--------------+ + | 1967-1973 | last Sun in Apr, 02:00 | -0400 | EDT | + | | | | | + | 1967-2006 | last Sun in Oct, 02:00 | -0500 | EST | + | | | | | + | 1974-1974 | Jan 6, 02:00 | -0400 | EDT | + | | | | | + | 1975-1975 | Feb 23, 02:00 | -0400 | EDT | + | | | | | + | 1976-1986 | last Sun in Apr, 02:00 | -0400 | EDT | + | | | | | + | 1987-2006 | first Sun in Apr, 02:00 | -0400 | EDT | + | | | | | + | 2007-* | second Sun in Mar, 02:00 | -0400 | EDT | + | | | | | + | 2007-* | first Sun in Nov, 02:00 | -0500 | EST | + +-----------+--------------------------+--------+--------------+ + + Note: The specification of a global time zone registry is not + addressed by this document and is left for future study. + However, implementers may find the TZ database [TZDB] a useful + reference. It is an informal, public-domain collection of time + zone information, which is currently being maintained by + volunteer Internet participants, and is used in several + operating systems. This database contains current and + historical time zone information for a wide variety of + locations around the globe; it provides a time zone identifier + for every unique time zone rule set in actual use since 1970, + with historical data going back to the introduction of standard + time. + + + + + +Desruisseaux Standards Track [Page 64] + +RFC 5545 iCalendar September 2009 + + + Interoperability between two calendaring and scheduling + applications, especially for recurring events, to-dos or journal + entries, is dependent on the ability to capture and convey date + and time information in an unambiguous format. The specification + of current time zone information is integral to this behavior. + + If present, the "VTIMEZONE" calendar component defines the set of + Standard Time and Daylight Saving Time observances (or rules) for + a particular time zone for a given interval of time. The + "VTIMEZONE" calendar component cannot be nested within other + calendar components. Multiple "VTIMEZONE" calendar components can + exist in an iCalendar object. In this situation, each "VTIMEZONE" + MUST represent a unique time zone definition. This is necessary + for some classes of events, such as airline flights, that start in + one time zone and end in another. + + The "VTIMEZONE" calendar component MUST include the "TZID" + property and at least one definition of a "STANDARD" or "DAYLIGHT" + sub-component. The "STANDARD" or "DAYLIGHT" sub-component MUST + include the "DTSTART", "TZOFFSETFROM", and "TZOFFSETTO" + properties. + + An individual "VTIMEZONE" calendar component MUST be specified for + each unique "TZID" parameter value specified in the iCalendar + object. In addition, a "VTIMEZONE" calendar component, referred + to by a recurring calendar component, MUST provide valid time zone + information for all recurrence instances. + + Each "VTIMEZONE" calendar component consists of a collection of + one or more sub-components that describe the rule for a particular + observance (either a Standard Time or a Daylight Saving Time + observance). The "STANDARD" sub-component consists of a + collection of properties that describe Standard Time. The + "DAYLIGHT" sub-component consists of a collection of properties + that describe Daylight Saving Time. In general, this collection + of properties consists of: + + * the first onset DATE-TIME for the observance; + + * the last onset DATE-TIME for the observance, if a last onset is + known; + + * the offset to be applied for the observance; + + * a rule that describes the day and time when the observance + takes effect; + + * an optional name for the observance. + + + +Desruisseaux Standards Track [Page 65] + +RFC 5545 iCalendar September 2009 + + + For a given time zone, there may be multiple unique definitions of + the observances over a period of time. Each observance is + described using either a "STANDARD" or "DAYLIGHT" sub-component. + The collection of these sub-components is used to describe the + time zone for a given period of time. The offset to apply at any + given time is found by locating the observance that has the last + onset date and time before the time in question, and using the + offset value from that observance. + + The top-level properties in a "VTIMEZONE" calendar component are: + + The mandatory "TZID" property is a text value that uniquely + identifies the "VTIMEZONE" calendar component within the scope of + an iCalendar object. + + The optional "LAST-MODIFIED" property is a UTC value that + specifies the date and time that this time zone definition was + last updated. + + The optional "TZURL" property is a url value that points to a + published "VTIMEZONE" definition. "TZURL" SHOULD refer to a + resource that is accessible by anyone who might need to interpret + the object. This SHOULD NOT normally be a "file" URL or other URL + that is not widely accessible. + + The collection of properties that are used to define the + "STANDARD" and "DAYLIGHT" sub-components include: + + The mandatory "DTSTART" property gives the effective onset date + and local time for the time zone sub-component definition. + "DTSTART" in this usage MUST be specified as a date with a local + time value. + + The mandatory "TZOFFSETFROM" property gives the UTC offset that is + in use when the onset of this time zone observance begins. + "TZOFFSETFROM" is combined with "DTSTART" to define the effective + onset for the time zone sub-component definition. For example, + the following represents the time at which the observance of + Standard Time took effect in Fall 1967 for New York City: + + DTSTART:19671029T020000 + + TZOFFSETFROM:-0400 + + The mandatory "TZOFFSETTO" property gives the UTC offset for the + time zone sub-component (Standard Time or Daylight Saving Time) + when this observance is in use. + + + + +Desruisseaux Standards Track [Page 66] + +RFC 5545 iCalendar September 2009 + + + The optional "TZNAME" property is the customary name for the time + zone. This could be used for displaying dates. + + The onset DATE-TIME values for the observance defined by the time + zone sub-component is defined by the "DTSTART", "RRULE", and + "RDATE" properties. + + The "RRULE" property defines the recurrence rule for the onset of + the observance defined by this time zone sub-component. Some + specific requirements for the usage of "RRULE" for this purpose + include: + + * If observance is known to have an effective end date, the + "UNTIL" recurrence rule parameter MUST be used to specify the + last valid onset of this observance (i.e., the UNTIL DATE-TIME + will be equal to the last instance generated by the recurrence + pattern). It MUST be specified in UTC time. + + * The "DTSTART" and the "TZOFFSETFROM" properties MUST be used + when generating the onset DATE-TIME values (instances) from the + "RRULE". + + The "RDATE" property can also be used to define the onset of the + observance by giving the individual onset date and times. "RDATE" + in this usage MUST be specified as a date with local time value, + relative to the UTC offset specified in the "TZOFFSETFROM" + property. + + The optional "COMMENT" property is also allowed for descriptive + explanatory text. + + Example: The following are examples of the "VTIMEZONE" calendar + component: + + This is an example showing all the time zone rules for New York + City since April 30, 1967 at 03:00:00 EDT. + + BEGIN:VTIMEZONE + TZID:America/New_York + LAST-MODIFIED:20050809T050000Z + BEGIN:DAYLIGHT + DTSTART:19670430T020000 + RRULE:FREQ=YEARLY;BYMONTH=4;BYDAY=-1SU;UNTIL=19730429T070000Z + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + BEGIN:STANDARD + + + +Desruisseaux Standards Track [Page 67] + +RFC 5545 iCalendar September 2009 + + + DTSTART:19671029T020000 + RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU;UNTIL=20061029T060000Z + TZOFFSETFROM:-0400 + TZOFFSETTO:-0500 + TZNAME:EST + END:STANDARD + BEGIN:DAYLIGHT + DTSTART:19740106T020000 + RDATE:19750223T020000 + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + BEGIN:DAYLIGHT + DTSTART:19760425T020000 + RRULE:FREQ=YEARLY;BYMONTH=4;BYDAY=-1SU;UNTIL=19860427T070000Z + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + BEGIN:DAYLIGHT + DTSTART:19870405T020000 + RRULE:FREQ=YEARLY;BYMONTH=4;BYDAY=1SU;UNTIL=20060402T070000Z + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + BEGIN:DAYLIGHT + DTSTART:20070311T020000 + RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + BEGIN:STANDARD + DTSTART:20071104T020000 + RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU + TZOFFSETFROM:-0400 + TZOFFSETTO:-0500 + TZNAME:EST + END:STANDARD + END:VTIMEZONE + + This is an example showing time zone information for New York City + using only the "DTSTART" property. Note that this is only + suitable for a recurring event that starts on or later than March + 11, 2007 at 03:00:00 EDT (i.e., the earliest effective transition + date and time) and ends no later than March 9, 2008 at 01:59:59 + + + +Desruisseaux Standards Track [Page 68] + +RFC 5545 iCalendar September 2009 + + + EST (i.e., latest valid date and time for EST in this scenario). + For example, this can be used for a recurring event that occurs + every Friday, 8:00 A.M.-9:00 A.M., starting June 1, 2007, ending + December 31, 2007, + + BEGIN:VTIMEZONE + TZID:America/New_York + LAST-MODIFIED:20050809T050000Z + BEGIN:STANDARD + DTSTART:20071104T020000 + TZOFFSETFROM:-0400 + TZOFFSETTO:-0500 + TZNAME:EST + END:STANDARD + BEGIN:DAYLIGHT + DTSTART:20070311T020000 + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + END:VTIMEZONE + + This is a simple example showing the current time zone rules for + New York City using a "RRULE" recurrence pattern. Note that there + is no effective end date to either of the Standard Time or + Daylight Time rules. This information would be valid for a + recurring event starting today and continuing indefinitely. + + BEGIN:VTIMEZONE + TZID:America/New_York + LAST-MODIFIED:20050809T050000Z + TZURL:http://zones.example.com/tz/America-New_York.ics + BEGIN:STANDARD + DTSTART:20071104T020000 + RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU + TZOFFSETFROM:-0400 + TZOFFSETTO:-0500 + TZNAME:EST + END:STANDARD + BEGIN:DAYLIGHT + DTSTART:20070311T020000 + RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + END:VTIMEZONE + + + + +Desruisseaux Standards Track [Page 69] + +RFC 5545 iCalendar September 2009 + + + This is an example showing a set of rules for a fictitious time + zone where the Daylight Time rule has an effective end date (i.e., + after that date, Daylight Time is no longer observed). + + BEGIN:VTIMEZONE + TZID:Fictitious + LAST-MODIFIED:19870101T000000Z + BEGIN:STANDARD + DTSTART:19671029T020000 + RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 + TZOFFSETFROM:-0400 + TZOFFSETTO:-0500 + TZNAME:EST + END:STANDARD + BEGIN:DAYLIGHT + DTSTART:19870405T020000 + RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000Z + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + END:VTIMEZONE + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 70] + +RFC 5545 iCalendar September 2009 + + + This is an example showing a set of rules for a fictitious time + zone where the first Daylight Time rule has an effective end date. + There is a second Daylight Time rule that picks up where the other + left off. + + BEGIN:VTIMEZONE + TZID:Fictitious + LAST-MODIFIED:19870101T000000Z + BEGIN:STANDARD + DTSTART:19671029T020000 + RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10 + TZOFFSETFROM:-0400 + TZOFFSETTO:-0500 + TZNAME:EST + END:STANDARD + BEGIN:DAYLIGHT + DTSTART:19870405T020000 + RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=4;UNTIL=19980404T070000Z + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + BEGIN:DAYLIGHT + DTSTART:19990424T020000 + RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=4 + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + TZNAME:EDT + END:DAYLIGHT + END:VTIMEZONE + +3.6.6. Alarm Component + + Component Name: VALARM + + Purpose: Provide a grouping of component properties that define an + alarm. + + Format Definition: A "VALARM" calendar component is defined by the + following notation: + + alarmc = "BEGIN" ":" "VALARM" CRLF + (audioprop / dispprop / emailprop) + "END" ":" "VALARM" CRLF + + audioprop = *( + ; + ; 'action' and 'trigger' are both REQUIRED, + + + +Desruisseaux Standards Track [Page 71] + +RFC 5545 iCalendar September 2009 + + + ; but MUST NOT occur more than once. + ; + action / trigger / + ; + ; 'duration' and 'repeat' are both OPTIONAL, + ; and MUST NOT occur more than once each; + ; but if one occurs, so MUST the other. + ; + duration / repeat / + ; + ; The following is OPTIONAL, + ; but MUST NOT occur more than once. + ; + attach / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + x-prop / iana-prop + ; + ) + + dispprop = *( + ; + ; The following are REQUIRED, + ; but MUST NOT occur more than once. + ; + action / description / trigger / + ; + ; 'duration' and 'repeat' are both OPTIONAL, + ; and MUST NOT occur more than once each; + ; but if one occurs, so MUST the other. + ; + duration / repeat / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + x-prop / iana-prop + ; + ) + + emailprop = *( + ; + ; The following are all REQUIRED, + ; but MUST NOT occur more than once. + ; + action / description / trigger / summary / + + + +Desruisseaux Standards Track [Page 72] + +RFC 5545 iCalendar September 2009 + + + ; + ; The following is REQUIRED, + ; and MAY occur more than once. + ; + attendee / + ; + ; 'duration' and 'repeat' are both OPTIONAL, + ; and MUST NOT occur more than once each; + ; but if one occurs, so MUST the other. + ; + duration / repeat / + ; + ; The following are OPTIONAL, + ; and MAY occur more than once. + ; + attach / x-prop / iana-prop + ; + ) + + Description: A "VALARM" calendar component is a grouping of + component properties that is a reminder or alarm for an event or a + to-do. For example, it may be used to define a reminder for a + pending event or an overdue to-do. + + The "VALARM" calendar component MUST include the "ACTION" and + "TRIGGER" properties. The "ACTION" property further constrains + the "VALARM" calendar component in the following ways: + + When the action is "AUDIO", the alarm can also include one and + only one "ATTACH" property, which MUST point to a sound resource, + which is rendered when the alarm is triggered. + + When the action is "DISPLAY", the alarm MUST also include a + "DESCRIPTION" property, which contains the text to be displayed + when the alarm is triggered. + + When the action is "EMAIL", the alarm MUST include a "DESCRIPTION" + property, which contains the text to be used as the message body, + a "SUMMARY" property, which contains the text to be used as the + message subject, and one or more "ATTENDEE" properties, which + contain the email address of attendees to receive the message. It + can also include one or more "ATTACH" properties, which are + intended to be sent as message attachments. When the alarm is + triggered, the email message is sent. + + The "VALARM" calendar component MUST only appear within either a + "VEVENT" or "VTODO" calendar component. "VALARM" calendar + components cannot be nested. Multiple mutually independent + + + +Desruisseaux Standards Track [Page 73] + +RFC 5545 iCalendar September 2009 + + + "VALARM" calendar components can be specified for a single + "VEVENT" or "VTODO" calendar component. + + The "TRIGGER" property specifies when the alarm will be triggered. + The "TRIGGER" property specifies a duration prior to the start of + an event or a to-do. The "TRIGGER" edge may be explicitly set to + be relative to the "START" or "END" of the event or to-do with the + "RELATED" parameter of the "TRIGGER" property. The "TRIGGER" + property value type can alternatively be set to an absolute + calendar date with UTC time. + + In an alarm set to trigger on the "START" of an event or to-do, + the "DTSTART" property MUST be present in the associated event or + to-do. In an alarm in a "VEVENT" calendar component set to + trigger on the "END" of the event, either the "DTEND" property + MUST be present, or the "DTSTART" and "DURATION" properties MUST + both be present. In an alarm in a "VTODO" calendar component set + to trigger on the "END" of the to-do, either the "DUE" property + MUST be present, or the "DTSTART" and "DURATION" properties MUST + both be present. + + The alarm can be defined such that it triggers repeatedly. A + definition of an alarm with a repeating trigger MUST include both + the "DURATION" and "REPEAT" properties. The "DURATION" property + specifies the delay period, after which the alarm will repeat. + The "REPEAT" property specifies the number of additional + repetitions that the alarm will be triggered. This repetition + count is in addition to the initial triggering of the alarm. Both + of these properties MUST be present in order to specify a + repeating alarm. If one of these two properties is absent, then + the alarm will not repeat beyond the initial trigger. + + The "ACTION" property is used within the "VALARM" calendar + component to specify the type of action invoked when the alarm is + triggered. The "VALARM" properties provide enough information for + a specific action to be invoked. It is typically the + responsibility of a "Calendar User Agent" (CUA) to deliver the + alarm in the specified fashion. An "ACTION" property value of + AUDIO specifies an alarm that causes a sound to be played to alert + the user; DISPLAY specifies an alarm that causes a text message to + be displayed to the user; and EMAIL specifies an alarm that causes + an electronic email message to be delivered to one or more email + addresses. + + In an AUDIO alarm, if the optional "ATTACH" property is included, + it MUST specify an audio sound resource. The intention is that + the sound will be played as the alarm effect. If an "ATTACH" + property is specified that does not refer to a sound resource, or + + + +Desruisseaux Standards Track [Page 74] + +RFC 5545 iCalendar September 2009 + + + if the specified sound resource cannot be rendered (because its + format is unsupported, or because it cannot be retrieved), then + the CUA or other entity responsible for playing the sound may + choose a fallback action, such as playing a built-in default + sound, or playing no sound at all. + + In a DISPLAY alarm, the intended alarm effect is for the text + value of the "DESCRIPTION" property to be displayed to the user. + + In an EMAIL alarm, the intended alarm effect is for an email + message to be composed and delivered to all the addresses + specified by the "ATTENDEE" properties in the "VALARM" calendar + component. The "DESCRIPTION" property of the "VALARM" calendar + component MUST be used as the body text of the message, and the + "SUMMARY" property MUST be used as the subject text. Any "ATTACH" + properties in the "VALARM" calendar component SHOULD be sent as + attachments to the message. + + Note: Implementations should carefully consider whether they + accept alarm components from untrusted sources, e.g., when + importing calendar objects from external sources. One + reasonable policy is to always ignore alarm components that the + calendar user has not set herself, or at least ask for + confirmation in such a case. + + Example: The following example is for a "VALARM" calendar component + that specifies an audio alarm that will sound at a precise time + and repeat 4 more times at 15-minute intervals: + + BEGIN:VALARM + TRIGGER;VALUE=DATE-TIME:19970317T133000Z + REPEAT:4 + DURATION:PT15M + ACTION:AUDIO + ATTACH;FMTTYPE=audio/basic:ftp://example.com/pub/ + sounds/bell-01.aud + END:VALARM + + The following example is for a "VALARM" calendar component that + specifies a display alarm that will trigger 30 minutes before the + scheduled start of the event or of the to-do it is associated with + and will repeat 2 more times at 15-minute intervals: + + + + + + + + + +Desruisseaux Standards Track [Page 75] + +RFC 5545 iCalendar September 2009 + + + BEGIN:VALARM + TRIGGER:-PT30M + REPEAT:2 + DURATION:PT15M + ACTION:DISPLAY + DESCRIPTION:Breakfast meeting with executive\n + team at 8:30 AM EST. + END:VALARM + + The following example is for a "VALARM" calendar component that + specifies an email alarm that will trigger 2 days before the + scheduled due DATE-TIME of a to-do with which it is associated. + It does not repeat. The email has a subject, body, and attachment + link. + + BEGIN:VALARM + TRIGGER;RELATED=END:-P2D + ACTION:EMAIL + ATTENDEE:mailto:john_doe@example.com + SUMMARY:*** REMINDER: SEND AGENDA FOR WEEKLY STAFF MEETING *** + DESCRIPTION:A draft agenda needs to be sent out to the attendees + to the weekly managers meeting (MGR-LIST). Attached is a + pointer the document template for the agenda file. + ATTACH;FMTTYPE=application/msword:http://example.com/ + templates/agenda.doc + END:VALARM + +3.7. Calendar Properties + + The Calendar Properties are attributes that apply to the iCalendar + object, as a whole. These properties do not appear within a calendar + component. They SHOULD be specified after the "BEGIN:VCALENDAR" + delimiter string and prior to any calendar component. + +3.7.1. Calendar Scale + + Property Name: CALSCALE + + Purpose: This property defines the calendar scale used for the + calendar information specified in the iCalendar object. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified once in an iCalendar + object. The default value is "GREGORIAN". + + + +Desruisseaux Standards Track [Page 76] + +RFC 5545 iCalendar September 2009 + + + Description: This memo is based on the Gregorian calendar scale. + The Gregorian calendar scale is assumed if this property is not + specified in the iCalendar object. It is expected that other + calendar scales will be defined in other specifications or by + future versions of this memo. + + Format Definition: This property is defined by the following + notation: + + calscale = "CALSCALE" calparam ":" calvalue CRLF + + calparam = *(";" other-param) + + calvalue = "GREGORIAN" + + Example: The following is an example of this property: + + CALSCALE:GREGORIAN + +3.7.2. Method + + Property Name: METHOD + + Purpose: This property defines the iCalendar object method + associated with the calendar object. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified once in an iCalendar + object. + + Description: When used in a MIME message entity, the value of this + property MUST be the same as the Content-Type "method" parameter + value. If either the "METHOD" property or the Content-Type + "method" parameter is specified, then the other MUST also be + specified. + + No methods are defined by this specification. This is the subject + of other specifications, such as the iCalendar Transport- + independent Interoperability Protocol (iTIP) defined by [2446bis]. + + If this property is not present in the iCalendar object, then a + scheduling transaction MUST NOT be assumed. In such cases, the + iCalendar object is merely being used to transport a snapshot of + + + + +Desruisseaux Standards Track [Page 77] + +RFC 5545 iCalendar September 2009 + + + some calendar information; without the intention of conveying a + scheduling semantic. + + Format Definition: This property is defined by the following + notation: + + method = "METHOD" metparam ":" metvalue CRLF + + metparam = *(";" other-param) + + metvalue = iana-token + + Example: The following is a hypothetical example of this property to + convey that the iCalendar object is a scheduling request: + + METHOD:REQUEST + +3.7.3. Product Identifier + + Property Name: PRODID + + Purpose: This property specifies the identifier for the product that + created the iCalendar object. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: The property MUST be specified once in an iCalendar + object. + + Description: The vendor of the implementation SHOULD assure that + this is a globally unique identifier; using some technique such as + an FPI value, as defined in [ISO.9070.1991]. + + This property SHOULD NOT be used to alter the interpretation of an + iCalendar object beyond the semantics specified in this memo. For + example, it is not to be used to further the understanding of non- + standard properties. + + Format Definition: This property is defined by the following + notation: + + prodid = "PRODID" pidparam ":" pidvalue CRLF + + pidparam = *(";" other-param) + + + + +Desruisseaux Standards Track [Page 78] + +RFC 5545 iCalendar September 2009 + + + pidvalue = text + ;Any text that describes the product and version + ;and that is generally assured of being unique. + + Example: The following is an example of this property. It does not + imply that English is the default language. + + PRODID:-//ABC Corporation//NONSGML My Product//EN + +3.7.4. Version + + Property Name: VERSION + + Purpose: This property specifies the identifier corresponding to the + highest version number or the minimum and maximum range of the + iCalendar specification that is required in order to interpret the + iCalendar object. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property MUST be specified once in an iCalendar + object. + + Description: A value of "2.0" corresponds to this memo. + + Format Definition: This property is defined by the following + notation: + + version = "VERSION" verparam ":" vervalue CRLF + + verparam = *(";" other-param) + + vervalue = "2.0" ;This memo + / maxver + / (minver ";" maxver) + + minver = + ;Minimum iCalendar version needed to parse the iCalendar object. + + maxver = + ;Maximum iCalendar version needed to parse the iCalendar object. + + + + + + + +Desruisseaux Standards Track [Page 79] + +RFC 5545 iCalendar September 2009 + + + Example: The following is an example of this property: + + VERSION:2.0 + +3.8. Component Properties + + The following properties can appear within calendar components, as + specified by each component property definition. + +3.8.1. Descriptive Component Properties + + The following properties specify descriptive information about + calendar components. + +3.8.1.1. Attachment + + Property Name: ATTACH + + Purpose: This property provides the capability to associate a + document object with a calendar component. + + Value Type: The default value type for this property is URI. The + value type can also be set to BINARY to indicate inline binary + encoded content information. + + Property Parameters: IANA, non-standard, inline encoding, and value + data type property parameters can be specified on this property. + The format type parameter can be specified on this property and is + RECOMMENDED for inline binary encoded content information. + + Conformance: This property can be specified multiple times in a + "VEVENT", "VTODO", "VJOURNAL", or "VALARM" calendar component with + the exception of AUDIO alarm that only allows this property to + occur once. + + Description: This property is used in "VEVENT", "VTODO", and + "VJOURNAL" calendar components to associate a resource (e.g., + document) with the calendar component. This property is used in + "VALARM" calendar components to specify an audio sound resource or + an email message attachment. This property can be specified as a + URI pointing to a resource or as inline binary encoded content. + + When this property is specified as inline binary encoded content, + calendar applications MAY attempt to guess the media type of the + resource via inspection of its content if and only if the media + type of the resource is not given by the "FMTTYPE" parameter. If + the media type remains unknown, calendar applications SHOULD treat + it as type "application/octet-stream". + + + +Desruisseaux Standards Track [Page 80] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This property is defined by the following + notation: + + attach = "ATTACH" attachparam ( ":" uri ) / + ( + ";" "ENCODING" "=" "BASE64" + ";" "VALUE" "=" "BINARY" + ":" binary + ) + CRLF + + attachparam = *( + ; + ; The following is OPTIONAL for a URI value, + ; RECOMMENDED for a BINARY value, + ; and MUST NOT occur more than once. + ; + (";" fmttypeparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following are examples of this property: + + ATTACH:CID:jsmith.part3.960817T083000.xyzMail@example.com + + ATTACH;FMTTYPE=application/postscript:ftp://example.com/pub/ + reports/r-960812.ps + +3.8.1.2. Categories + + Property Name: CATEGORIES + + Purpose: This property defines the categories for a calendar + component. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, and language property + parameters can be specified on this property. + + Conformance: The property can be specified within "VEVENT", "VTODO", + or "VJOURNAL" calendar components. + + + + +Desruisseaux Standards Track [Page 81] + +RFC 5545 iCalendar September 2009 + + + Description: This property is used to specify categories or subtypes + of the calendar component. The categories are useful in searching + for a calendar component of a particular type and category. + Within the "VEVENT", "VTODO", or "VJOURNAL" calendar components, + more than one category can be specified as a COMMA-separated list + of categories. + + Format Definition: This property is defined by the following + notation: + + categories = "CATEGORIES" catparam ":" text *("," text) + CRLF + + catparam = *( + ; + ; The following is OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" languageparam ) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following are examples of this property: + + CATEGORIES:APPOINTMENT,EDUCATION + + CATEGORIES:MEETING + +3.8.1.3. Classification + + Property Name: CLASS + + Purpose: This property defines the access classification for a + calendar component. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: The property can be specified once in a "VEVENT", + "VTODO", or "VJOURNAL" calendar components. + + + + +Desruisseaux Standards Track [Page 82] + +RFC 5545 iCalendar September 2009 + + + Description: An access classification is only one component of the + general security system within a calendar application. It + provides a method of capturing the scope of the access the + calendar owner intends for information within an individual + calendar entry. The access classification of an individual + iCalendar component is useful when measured along with the other + security components of a calendar system (e.g., calendar user + authentication, authorization, access rights, access role, etc.). + Hence, the semantics of the individual access classifications + cannot be completely defined by this memo alone. Additionally, + due to the "blind" nature of most exchange processes using this + memo, these access classifications cannot serve as an enforcement + statement for a system receiving an iCalendar object. Rather, + they provide a method for capturing the intention of the calendar + owner for the access to the calendar component. If not specified + in a component that allows this property, the default value is + PUBLIC. Applications MUST treat x-name and iana-token values they + don't recognize the same way as they would the PRIVATE value. + + Format Definition: This property is defined by the following + notation: + + class = "CLASS" classparam ":" classvalue CRLF + + classparam = *(";" other-param) + + classvalue = "PUBLIC" / "PRIVATE" / "CONFIDENTIAL" / iana-token + / x-name + ;Default is PUBLIC + + Example: The following is an example of this property: + + CLASS:PUBLIC + +3.8.1.4. Comment + + Property Name: COMMENT + + Purpose: This property specifies non-processing information intended + to provide a comment to the calendar user. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, alternate text + representation, and language property parameters can be specified + on this property. + + + + + +Desruisseaux Standards Track [Page 83] + +RFC 5545 iCalendar September 2009 + + + Conformance: This property can be specified multiple times in + "VEVENT", "VTODO", "VJOURNAL", and "VFREEBUSY" calendar components + as well as in the "STANDARD" and "DAYLIGHT" sub-components. + + Description: This property is used to specify a comment to the + calendar user. + + Format Definition: This property is defined by the following + notation: + + comment = "COMMENT" commparam ":" text CRLF + + commparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" altrepparam) / (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following is an example of this property: + + COMMENT:The meeting really needs to include both ourselves + and the customer. We can't hold this meeting without them. + As a matter of fact\, the venue for the meeting ought to be at + their site. - - John + +3.8.1.5. Description + + Property Name: DESCRIPTION + + Purpose: This property provides a more complete description of the + calendar component than that provided by the "SUMMARY" property. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, alternate text + representation, and language property parameters can be specified + on this property. + + + + + + +Desruisseaux Standards Track [Page 84] + +RFC 5545 iCalendar September 2009 + + + Conformance: The property can be specified in the "VEVENT", "VTODO", + "VJOURNAL", or "VALARM" calendar components. The property can be + specified multiple times only within a "VJOURNAL" calendar + component. + + Description: This property is used in the "VEVENT" and "VTODO" to + capture lengthy textual descriptions associated with the activity. + + This property is used in the "VJOURNAL" calendar component to + capture one or more textual journal entries. + + This property is used in the "VALARM" calendar component to + capture the display text for a DISPLAY category of alarm, and to + capture the body text for an EMAIL category of alarm. + + Format Definition: This property is defined by the following + notation: + + description = "DESCRIPTION" descparam ":" text CRLF + + descparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" altrepparam) / (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following is an example of this property with formatted + line breaks in the property value: + + DESCRIPTION:Meeting to provide technical review for "Phoenix" + design.\nHappy Face Conference Room. Phoenix design team + MUST attend this meeting.\nRSVP to team leader. + +3.8.1.6. Geographic Position + + Property Name: GEO + + Purpose: This property specifies information related to the global + position for the activity specified by a calendar component. + + + + +Desruisseaux Standards Track [Page 85] + +RFC 5545 iCalendar September 2009 + + + Value Type: FLOAT. The value MUST be two SEMICOLON-separated FLOAT + values. + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified in "VEVENT" or "VTODO" + calendar components. + + Description: This property value specifies latitude and longitude, + in that order (i.e., "LAT LON" ordering). The longitude + represents the location east or west of the prime meridian as a + positive or negative real number, respectively. The longitude and + latitude values MAY be specified up to six decimal places, which + will allow for accuracy to within one meter of geographical + position. Receiving applications MUST accept values of this + precision and MAY truncate values of greater precision. + + Values for latitude and longitude shall be expressed as decimal + fractions of degrees. Whole degrees of latitude shall be + represented by a two-digit decimal number ranging from 0 through + 90. Whole degrees of longitude shall be represented by a decimal + number ranging from 0 through 180. When a decimal fraction of a + degree is specified, it shall be separated from the whole number + of degrees by a decimal point. + + Latitudes north of the equator shall be specified by a plus sign + (+), or by the absence of a minus sign (-), preceding the digits + designating degrees. Latitudes south of the Equator shall be + designated by a minus sign (-) preceding the digits designating + degrees. A point on the Equator shall be assigned to the Northern + Hemisphere. + + Longitudes east of the prime meridian shall be specified by a plus + sign (+), or by the absence of a minus sign (-), preceding the + digits designating degrees. Longitudes west of the meridian shall + be designated by minus sign (-) preceding the digits designating + degrees. A point on the prime meridian shall be assigned to the + Eastern Hemisphere. A point on the 180th meridian shall be + assigned to the Western Hemisphere. One exception to this last + convention is permitted. For the special condition of describing + a band of latitude around the earth, the East Bounding Coordinate + data element shall be assigned the value +180 (180) degrees. + + Any spatial address with a latitude of +90 (90) or -90 degrees + will specify the position at the North or South Pole, + respectively. The component for longitude may have any legal + value. + + + +Desruisseaux Standards Track [Page 86] + +RFC 5545 iCalendar September 2009 + + + With the exception of the special condition described above, this + form is specified in [ANSI INCITS 61-1986]. + + The simple formula for converting degrees-minutes-seconds into + decimal degrees is: + + decimal = degrees + minutes/60 + seconds/3600. + + Format Definition: This property is defined by the following + notation: + + geo = "GEO" geoparam ":" geovalue CRLF + + geoparam = *(";" other-param) + + geovalue = float ";" float + ;Latitude and Longitude components + + Example: The following is an example of this property: + + GEO:37.386013;-122.082932 + +3.8.1.7. Location + + Property Name: LOCATION + + Purpose: This property defines the intended venue for the activity + defined by a calendar component. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, alternate text + representation, and language property parameters can be specified + on this property. + + Conformance: This property can be specified in "VEVENT" or "VTODO" + calendar component. + + Description: Specific venues such as conference or meeting rooms may + be explicitly specified using this property. An alternate + representation may be specified that is a URI that points to + directory information with more structured specification of the + location. For example, the alternate representation may specify + either an LDAP URL [RFC4516] pointing to an LDAP server entry or a + CID URL [RFC2392] pointing to a MIME body part containing a + Virtual-Information Card (vCard) [RFC2426] for the location. + + + + + +Desruisseaux Standards Track [Page 87] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This property is defined by the following + notation: + + location = "LOCATION" locparam ":" text CRLF + + locparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" altrepparam) / (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following are some examples of this property: + + LOCATION:Conference Room - F123\, Bldg. 002 + + LOCATION;ALTREP="http://xyzcorp.com/conf-rooms/f123.vcf": + Conference Room - F123\, Bldg. 002 + +3.8.1.8. Percent Complete + + Property Name: PERCENT-COMPLETE + + Purpose: This property is used by an assignee or delegatee of a + to-do to convey the percent completion of a to-do to the + "Organizer". + + Value Type: INTEGER + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified once in a "VTODO" + calendar component. + + Description: The property value is a positive integer between 0 and + 100. A value of "0" indicates the to-do has not yet been started. + A value of "100" indicates that the to-do has been completed. + Integer values in between indicate the percent partially complete. + + + + + +Desruisseaux Standards Track [Page 88] + +RFC 5545 iCalendar September 2009 + + + When a to-do is assigned to multiple individuals, the property + value indicates the percent complete for that portion of the to-do + assigned to the assignee or delegatee. For example, if a to-do is + assigned to both individuals "A" and "B". A reply from "A" with a + percent complete of "70" indicates that "A" has completed 70% of + the to-do assigned to them. A reply from "B" with a percent + complete of "50" indicates "B" has completed 50% of the to-do + assigned to them. + + Format Definition: This property is defined by the following + notation: + + percent = "PERCENT-COMPLETE" pctparam ":" integer CRLF + + pctparam = *(";" other-param) + + Example: The following is an example of this property to show 39% + completion: + + PERCENT-COMPLETE:39 + +3.8.1.9. Priority + + Property Name: PRIORITY + + Purpose: This property defines the relative priority for a calendar + component. + + Value Type: INTEGER + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified in "VEVENT" and "VTODO" + calendar components. + + Description: This priority is specified as an integer in the range 0 + to 9. A value of 0 specifies an undefined priority. A value of 1 + is the highest priority. A value of 2 is the second highest + priority. Subsequent numbers specify a decreasing ordinal + priority. A value of 9 is the lowest priority. + + A CUA with a three-level priority scheme of "HIGH", "MEDIUM", and + "LOW" is mapped into this property such that a property value in + the range of 1 to 4 specifies "HIGH" priority. A value of 5 is + the normal or "MEDIUM" priority. A value in the range of 6 to 9 + is "LOW" priority. + + + + +Desruisseaux Standards Track [Page 89] + +RFC 5545 iCalendar September 2009 + + + A CUA with a priority schema of "A1", "A2", "A3", "B1", "B2", ..., + "C3" is mapped into this property such that a property value of 1 + specifies "A1", a property value of 2 specifies "A2", a property + value of 3 specifies "A3", and so forth up to a property value of + 9 specifies "C3". + + Other integer values are reserved for future use. + + Within a "VEVENT" calendar component, this property specifies a + priority for the event. This property may be useful when more + than one event is scheduled for a given time period. + + Within a "VTODO" calendar component, this property specified a + priority for the to-do. This property is useful in prioritizing + multiple action items for a given time period. + + Format Definition: This property is defined by the following + notation: + + priority = "PRIORITY" prioparam ":" priovalue CRLF + ;Default is zero (i.e., undefined). + + prioparam = *(";" other-param) + + priovalue = integer ;Must be in the range [0..9] + ; All other values are reserved for future use. + + Example: The following is an example of a property with the highest + priority: + + PRIORITY:1 + + The following is an example of a property with a next highest + priority: + + PRIORITY:2 + + The following is an example of a property with no priority. This + is equivalent to not specifying the "PRIORITY" property: + + PRIORITY:0 + + + + + + + + + + +Desruisseaux Standards Track [Page 90] + +RFC 5545 iCalendar September 2009 + + +3.8.1.10. Resources + + Property Name: RESOURCES + + Purpose: This property defines the equipment or resources + anticipated for an activity specified by a calendar component. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, alternate text + representation, and language property parameters can be specified + on this property. + + Conformance: This property can be specified once in "VEVENT" or + "VTODO" calendar component. + + Description: The property value is an arbitrary text. More than one + resource can be specified as a COMMA-separated list of resources. + + Format Definition: This property is defined by the following + notation: + + resources = "RESOURCES" resrcparam ":" text *("," text) CRLF + + resrcparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" altrepparam) / (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following is an example of this property: + + RESOURCES:EASEL,PROJECTOR,VCR + + RESOURCES;LANGUAGE=fr:Nettoyeur haute pression + + + + + + + + +Desruisseaux Standards Track [Page 91] + +RFC 5545 iCalendar September 2009 + + +3.8.1.11. Status + + Property Name: STATUS + + Purpose: This property defines the overall status or confirmation + for the calendar component. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified once in "VEVENT", + "VTODO", or "VJOURNAL" calendar components. + + Description: In a group-scheduled calendar component, the property + is used by the "Organizer" to provide a confirmation of the event + to the "Attendees". For example in a "VEVENT" calendar component, + the "Organizer" can indicate that a meeting is tentative, + confirmed, or cancelled. In a "VTODO" calendar component, the + "Organizer" can indicate that an action item needs action, is + completed, is in process or being worked on, or has been + cancelled. In a "VJOURNAL" calendar component, the "Organizer" + can indicate that a journal entry is draft, final, or has been + cancelled or removed. + + Format Definition: This property is defined by the following + notation: + + status = "STATUS" statparam ":" statvalue CRLF + + statparam = *(";" other-param) + + statvalue = (statvalue-event + / statvalue-todo + / statvalue-jour) + + statvalue-event = "TENTATIVE" ;Indicates event is tentative. + / "CONFIRMED" ;Indicates event is definite. + / "CANCELLED" ;Indicates event was cancelled. + ;Status values for a "VEVENT" + + statvalue-todo = "NEEDS-ACTION" ;Indicates to-do needs action. + / "COMPLETED" ;Indicates to-do completed. + / "IN-PROCESS" ;Indicates to-do in process of. + / "CANCELLED" ;Indicates to-do was cancelled. + ;Status values for "VTODO". + + + + +Desruisseaux Standards Track [Page 92] + +RFC 5545 iCalendar September 2009 + + + statvalue-jour = "DRAFT" ;Indicates journal is draft. + / "FINAL" ;Indicates journal is final. + / "CANCELLED" ;Indicates journal is removed. + ;Status values for "VJOURNAL". + + Example: The following is an example of this property for a "VEVENT" + calendar component: + + STATUS:TENTATIVE + + The following is an example of this property for a "VTODO" + calendar component: + + STATUS:NEEDS-ACTION + + The following is an example of this property for a "VJOURNAL" + calendar component: + + STATUS:DRAFT + +3.8.1.12. Summary + + Property Name: SUMMARY + + Purpose: This property defines a short summary or subject for the + calendar component. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, alternate text + representation, and language property parameters can be specified + on this property. + + Conformance: The property can be specified in "VEVENT", "VTODO", + "VJOURNAL", or "VALARM" calendar components. + + Description: This property is used in the "VEVENT", "VTODO", and + "VJOURNAL" calendar components to capture a short, one-line + summary about the activity or journal entry. + + This property is used in the "VALARM" calendar component to + capture the subject of an EMAIL category of alarm. + + Format Definition: This property is defined by the following + notation: + + + + + + +Desruisseaux Standards Track [Page 93] + +RFC 5545 iCalendar September 2009 + + + summary = "SUMMARY" summparam ":" text CRLF + + summparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" altrepparam) / (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following is an example of this property: + + SUMMARY:Department Party + +3.8.2. Date and Time Component Properties + + The following properties specify date and time related information in + calendar components. + +3.8.2.1. Date-Time Completed + + Property Name: COMPLETED + + Purpose: This property defines the date and time that a to-do was + actually completed. + + Value Type: DATE-TIME + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: The property can be specified in a "VTODO" calendar + component. The value MUST be specified as a date with UTC time. + + Description: This property defines the date and time that a to-do + was actually completed. + + Format Definition: This property is defined by the following + notation: + + + + + + +Desruisseaux Standards Track [Page 94] + +RFC 5545 iCalendar September 2009 + + + completed = "COMPLETED" compparam ":" date-time CRLF + + compparam = *(";" other-param) + + Example: The following is an example of this property: + + COMPLETED:19960401T150000Z + +3.8.2.2. Date-Time End + + Property Name: DTEND + + Purpose: This property specifies the date and time that a calendar + component ends. + + Value Type: The default value type is DATE-TIME. The value type can + be set to a DATE value type. + + Property Parameters: IANA, non-standard, value data type, and time + zone identifier property parameters can be specified on this + property. + + Conformance: This property can be specified in "VEVENT" or + "VFREEBUSY" calendar components. + + Description: Within the "VEVENT" calendar component, this property + defines the date and time by which the event ends. The value type + of this property MUST be the same as the "DTSTART" property, and + its value MUST be later in time than the value of the "DTSTART" + property. Furthermore, this property MUST be specified as a date + with local time if and only if the "DTSTART" property is also + specified as a date with local time. + + Within the "VFREEBUSY" calendar component, this property defines + the end date and time for the free or busy time information. The + time MUST be specified in the UTC time format. The value MUST be + later in time than the value of the "DTSTART" property. + + Format Definition: This property is defined by the following + notation: + + + + + + + + + + + +Desruisseaux Standards Track [Page 95] + +RFC 5545 iCalendar September 2009 + + + dtend = "DTEND" dtendparam ":" dtendval CRLF + + dtendparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / + (";" tzidparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + dtendval = date-time / date + ;Value MUST match value type + + Example: The following is an example of this property: + + DTEND:19960401T150000Z + + DTEND;VALUE=DATE:19980704 + +3.8.2.3. Date-Time Due + + Property Name: DUE + + Purpose: This property defines the date and time that a to-do is + expected to be completed. + + Value Type: The default value type is DATE-TIME. The value type can + be set to a DATE value type. + + Property Parameters: IANA, non-standard, value data type, and time + zone identifier property parameters can be specified on this + property. + + Conformance: The property can be specified once in a "VTODO" + calendar component. + + Description: This property defines the date and time before which a + to-do is expected to be completed. For cases where this property + is specified in a "VTODO" calendar component that also specifies a + "DTSTART" property, the value type of this property MUST be the + same as the "DTSTART" property, and the value of this property + + + +Desruisseaux Standards Track [Page 96] + +RFC 5545 iCalendar September 2009 + + + MUST be later in time than the value of the "DTSTART" property. + Furthermore, this property MUST be specified as a date with local + time if and only if the "DTSTART" property is also specified as a + date with local time. + + Format Definition: This property is defined by the following + notation: + + due = "DUE" dueparam ":" dueval CRLF + + dueparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / + (";" tzidparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + dueval = date-time / date + ;Value MUST match value type + + Example: The following is an example of this property: + + DUE:19980430T000000Z + +3.8.2.4. Date-Time Start + + Property Name: DTSTART + + Purpose: This property specifies when the calendar component begins. + + Value Type: The default value type is DATE-TIME. The time value + MUST be one of the forms defined for the DATE-TIME value type. + The value type can be set to a DATE value type. + + Property Parameters: IANA, non-standard, value data type, and time + zone identifier property parameters can be specified on this + property. + + Conformance: This property can be specified once in the "VEVENT", + "VTODO", or "VFREEBUSY" calendar components as well as in the + + + +Desruisseaux Standards Track [Page 97] + +RFC 5545 iCalendar September 2009 + + + "STANDARD" and "DAYLIGHT" sub-components. This property is + REQUIRED in all types of recurring calendar components that + specify the "RRULE" property. This property is also REQUIRED in + "VEVENT" calendar components contained in iCalendar objects that + don't specify the "METHOD" property. + + Description: Within the "VEVENT" calendar component, this property + defines the start date and time for the event. + + Within the "VFREEBUSY" calendar component, this property defines + the start date and time for the free or busy time information. + The time MUST be specified in UTC time. + + Within the "STANDARD" and "DAYLIGHT" sub-components, this property + defines the effective start date and time for a time zone + specification. This property is REQUIRED within each "STANDARD" + and "DAYLIGHT" sub-components included in "VTIMEZONE" calendar + components and MUST be specified as a date with local time without + the "TZID" property parameter. + + Format Definition: This property is defined by the following + notation: + + dtstart = "DTSTART" dtstparam ":" dtstval CRLF + + dtstparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / + (";" tzidparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + dtstval = date-time / date + ;Value MUST match value type + + Example: The following is an example of this property: + + DTSTART:19980118T073000Z + + + + + +Desruisseaux Standards Track [Page 98] + +RFC 5545 iCalendar September 2009 + + +3.8.2.5. Duration + + Property Name: DURATION + + Purpose: This property specifies a positive duration of time. + + Value Type: DURATION + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified in "VEVENT", "VTODO", or + "VALARM" calendar components. + + Description: In a "VEVENT" calendar component the property may be + used to specify a duration of the event, instead of an explicit + end DATE-TIME. In a "VTODO" calendar component the property may + be used to specify a duration for the to-do, instead of an + explicit due DATE-TIME. In a "VALARM" calendar component the + property may be used to specify the delay period prior to + repeating an alarm. When the "DURATION" property relates to a + "DTSTART" property that is specified as a DATE value, then the + "DURATION" property MUST be specified as a "dur-day" or "dur-week" + value. + + Format Definition: This property is defined by the following + notation: + + duration = "DURATION" durparam ":" dur-value CRLF + ;consisting of a positive duration of time. + + durparam = *(";" other-param) + + Example: The following is an example of this property that specifies + an interval of time of one hour and zero minutes and zero seconds: + + DURATION:PT1H0M0S + + The following is an example of this property that specifies an + interval of time of 15 minutes. + + DURATION:PT15M + + + + + + + + + +Desruisseaux Standards Track [Page 99] + +RFC 5545 iCalendar September 2009 + + +3.8.2.6. Free/Busy Time + + Property Name: FREEBUSY + + Purpose: This property defines one or more free or busy time + intervals. + + Value Type: PERIOD + + Property Parameters: IANA, non-standard, and free/busy time type + property parameters can be specified on this property. + + Conformance: The property can be specified in a "VFREEBUSY" calendar + component. + + Description: These time periods can be specified as either a start + and end DATE-TIME or a start DATE-TIME and DURATION. The date and + time MUST be a UTC time format. + + "FREEBUSY" properties within the "VFREEBUSY" calendar component + SHOULD be sorted in ascending order, based on start time and then + end time, with the earliest periods first. + + The "FREEBUSY" property can specify more than one value, separated + by the COMMA character. In such cases, the "FREEBUSY" property + values MUST all be of the same "FBTYPE" property parameter type + (e.g., all values of a particular "FBTYPE" listed together in a + single property). + + Format Definition: This property is defined by the following + notation: + + freebusy = "FREEBUSY" fbparam ":" fbvalue CRLF + + fbparam = *( + ; + ; The following is OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" fbtypeparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + + + +Desruisseaux Standards Track [Page 100] + +RFC 5545 iCalendar September 2009 + + + fbvalue = period *("," period) + ;Time value MUST be in the UTC time format. + + Example: The following are some examples of this property: + + FREEBUSY;FBTYPE=BUSY-UNAVAILABLE:19970308T160000Z/PT8H30M + + FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H + + FREEBUSY;FBTYPE=FREE:19970308T160000Z/PT3H,19970308T200000Z/PT1H + ,19970308T230000Z/19970309T000000Z + +3.8.2.7. Time Transparency + + Property Name: TRANSP + + Purpose: This property defines whether or not an event is + transparent to busy time searches. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified once in a "VEVENT" + calendar component. + + Description: Time Transparency is the characteristic of an event + that determines whether it appears to consume time on a calendar. + Events that consume actual time for the individual or resource + associated with the calendar SHOULD be recorded as OPAQUE, + allowing them to be detected by free/busy time searches. Other + events, which do not take up the individual's (or resource's) time + SHOULD be recorded as TRANSPARENT, making them invisible to free/ + busy time searches. + + Format Definition: This property is defined by the following + notation: + + transp = "TRANSP" transparam ":" transvalue CRLF + + transparam = *(";" other-param) + + transvalue = "OPAQUE" + ;Blocks or opaque on busy time searches. + / "TRANSPARENT" + ;Transparent on busy time searches. + ;Default value is OPAQUE + + + +Desruisseaux Standards Track [Page 101] + +RFC 5545 iCalendar September 2009 + + + Example: The following is an example of this property for an event + that is transparent or does not block on free/busy time searches: + + TRANSP:TRANSPARENT + + The following is an example of this property for an event that is + opaque or blocks on free/busy time searches: + + TRANSP:OPAQUE + +3.8.3. Time Zone Component Properties + + The following properties specify time zone information in calendar + components. + +3.8.3.1. Time Zone Identifier + + Property Name: TZID + + Purpose: This property specifies the text value that uniquely + identifies the "VTIMEZONE" calendar component in the scope of an + iCalendar object. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property MUST be specified in a "VTIMEZONE" + calendar component. + + Description: This is the label by which a time zone calendar + component is referenced by any iCalendar properties whose value + type is either DATE-TIME or TIME and not intended to specify a UTC + or a "floating" time. The presence of the SOLIDUS character as a + prefix, indicates that this "TZID" represents an unique ID in a + globally defined time zone registry (when such registry is + defined). + + Note: This document does not define a naming convention for + time zone identifiers. Implementers may want to use the naming + conventions defined in existing time zone specifications such + as the public-domain TZ database [TZDB]. The specification of + globally unique time zone identifiers is not addressed by this + document and is left for future study. + + + + + + +Desruisseaux Standards Track [Page 102] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This property is defined by the following + notation: + + tzid = "TZID" tzidpropparam ":" [tzidprefix] text CRLF + + tzidpropparam = *(";" other-param) + + ;tzidprefix = "/" + ; Defined previously. Just listed here for reader convenience. + + Example: The following are examples of non-globally unique time zone + identifiers: + + TZID:America/New_York + + TZID:America/Los_Angeles + + The following is an example of a fictitious globally unique time + zone identifier: + + TZID:/example.org/America/New_York + +3.8.3.2. Time Zone Name + + Property Name: TZNAME + + Purpose: This property specifies the customary designation for a + time zone description. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, and language property + parameters can be specified on this property. + + Conformance: This property can be specified in "STANDARD" and + "DAYLIGHT" sub-components. + + Description: This property specifies a customary name that can be + used when displaying dates that occur during the observance + defined by the time zone sub-component. + + Format Definition: This property is defined by the following + notation: + + + + + + + + +Desruisseaux Standards Track [Page 103] + +RFC 5545 iCalendar September 2009 + + + tzname = "TZNAME" tznparam ":" text CRLF + + tznparam = *( + ; + ; The following is OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following are examples of this property: + + TZNAME:EST + + TZNAME;LANGUAGE=fr-CA:HNE + +3.8.3.3. Time Zone Offset From + + Property Name: TZOFFSETFROM + + Purpose: This property specifies the offset that is in use prior to + this time zone observance. + + Value Type: UTC-OFFSET + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property MUST be specified in "STANDARD" and + "DAYLIGHT" sub-components. + + Description: This property specifies the offset that is in use prior + to this time observance. It is used to calculate the absolute + time at which the transition to a given observance takes place. + This property MUST only be specified in a "VTIMEZONE" calendar + component. A "VTIMEZONE" calendar component MUST include this + property. The property value is a signed numeric indicating the + number of hours and possibly minutes from UTC. Positive numbers + represent time zones east of the prime meridian, or ahead of UTC. + Negative numbers represent time zones west of the prime meridian, + or behind UTC. + + + + +Desruisseaux Standards Track [Page 104] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This property is defined by the following + notation: + + tzoffsetfrom = "TZOFFSETFROM" frmparam ":" utc-offset + CRLF + + frmparam = *(";" other-param) + + Example: The following are examples of this property: + + TZOFFSETFROM:-0500 + + TZOFFSETFROM:+1345 + +3.8.3.4. Time Zone Offset To + + Property Name: TZOFFSETTO + + Purpose: This property specifies the offset that is in use in this + time zone observance. + + Value Type: UTC-OFFSET + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property MUST be specified in "STANDARD" and + "DAYLIGHT" sub-components. + + Description: This property specifies the offset that is in use in + this time zone observance. It is used to calculate the absolute + time for the new observance. The property value is a signed + numeric indicating the number of hours and possibly minutes from + UTC. Positive numbers represent time zones east of the prime + meridian, or ahead of UTC. Negative numbers represent time zones + west of the prime meridian, or behind UTC. + + Format Definition: This property is defined by the following + notation: + + tzoffsetto = "TZOFFSETTO" toparam ":" utc-offset CRLF + + toparam = *(";" other-param) + + + + + + + + +Desruisseaux Standards Track [Page 105] + +RFC 5545 iCalendar September 2009 + + + Example: The following are examples of this property: + + TZOFFSETTO:-0400 + + TZOFFSETTO:+1245 + +3.8.3.5. Time Zone URL + + Property Name: TZURL + + Purpose: This property provides a means for a "VTIMEZONE" component + to point to a network location that can be used to retrieve an up- + to-date version of itself. + + Value Type: URI + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified in a "VTIMEZONE" + calendar component. + + Description: This property provides a means for a "VTIMEZONE" + component to point to a network location that can be used to + retrieve an up-to-date version of itself. This provides a hook to + handle changes government bodies impose upon time zone + definitions. Retrieval of this resource results in an iCalendar + object containing a single "VTIMEZONE" component and a "METHOD" + property set to PUBLISH. + + Format Definition: This property is defined by the following + notation: + + tzurl = "TZURL" tzurlparam ":" uri CRLF + + tzurlparam = *(";" other-param) + + Example: The following is an example of this property: + + TZURL:http://timezones.example.org/tz/America-Los_Angeles.ics + +3.8.4. Relationship Component Properties + + The following properties specify relationship information in calendar + components. + + + + + + +Desruisseaux Standards Track [Page 106] + +RFC 5545 iCalendar September 2009 + + +3.8.4.1. Attendee + + Property Name: ATTENDEE + + Purpose: This property defines an "Attendee" within a calendar + component. + + Value Type: CAL-ADDRESS + + Property Parameters: IANA, non-standard, language, calendar user + type, group or list membership, participation role, participation + status, RSVP expectation, delegatee, delegator, sent by, common + name, or directory entry reference property parameters can be + specified on this property. + + Conformance: This property MUST be specified in an iCalendar object + that specifies a group-scheduled calendar entity. This property + MUST NOT be specified in an iCalendar object when publishing the + calendar information (e.g., NOT in an iCalendar object that + specifies the publication of a calendar user's busy time, event, + to-do, or journal). This property is not specified in an + iCalendar object that specifies only a time zone definition or + that defines calendar components that are not group-scheduled + components, but are components only on a single user's calendar. + + Description: This property MUST only be specified within calendar + components to specify participants, non-participants, and the + chair of a group-scheduled calendar entity. The property is + specified within an "EMAIL" category of the "VALARM" calendar + component to specify an email address that is to receive the email + type of iCalendar alarm. + + The property parameter "CN" is for the common or displayable name + associated with the calendar address; "ROLE", for the intended + role that the attendee will have in the calendar component; + "PARTSTAT", for the status of the attendee's participation; + "RSVP", for indicating whether the favor of a reply is requested; + "CUTYPE", to indicate the type of calendar user; "MEMBER", to + indicate the groups that the attendee belongs to; "DELEGATED-TO", + to indicate the calendar users that the original request was + delegated to; and "DELEGATED-FROM", to indicate whom the request + was delegated from; "SENT-BY", to indicate whom is acting on + behalf of the "ATTENDEE"; and "DIR", to indicate the URI that + points to the directory information corresponding to the attendee. + These property parameters can be specified on an "ATTENDEE" + property in either a "VEVENT", "VTODO", or "VJOURNAL" calendar + component. They MUST NOT be specified in an "ATTENDEE" property + in a "VFREEBUSY" or "VALARM" calendar component. If the + + + +Desruisseaux Standards Track [Page 107] + +RFC 5545 iCalendar September 2009 + + + "LANGUAGE" property parameter is specified, the identified + language applies to the "CN" parameter. + + A recipient delegated a request MUST inherit the "RSVP" and "ROLE" + values from the attendee that delegated the request to them. + + Multiple attendees can be specified by including multiple + "ATTENDEE" properties within the calendar component. + + Format Definition: This property is defined by the following + notation: + + attendee = "ATTENDEE" attparam ":" cal-address CRLF + + attparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" cutypeparam) / (";" memberparam) / + (";" roleparam) / (";" partstatparam) / + (";" rsvpparam) / (";" deltoparam) / + (";" delfromparam) / (";" sentbyparam) / + (";" cnparam) / (";" dirparam) / + (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following are examples of this property's use for a + to-do: + + ATTENDEE;MEMBER="mailto:DEV-GROUP@example.com": + mailto:joecool@example.com + ATTENDEE;DELEGATED-FROM="mailto:immud@example.com": + mailto:ildoit@example.com + + + + + + + + + + + +Desruisseaux Standards Track [Page 108] + +RFC 5545 iCalendar September 2009 + + + The following is an example of this property used for specifying + multiple attendees to an event: + + ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;CN=Henry + Cabot:mailto:hcabot@example.com + ATTENDEE;ROLE=REQ-PARTICIPANT;DELEGATED-FROM="mailto:bob@ + example.com";PARTSTAT=ACCEPTED;CN=Jane Doe:mailto:jdoe@ + example.com + + The following is an example of this property with a URI to the + directory information associated with the attendee: + + ATTENDEE;CN=John Smith;DIR="ldap://example.com:6666/o=ABC% + 20Industries,c=US???(cn=Jim%20Dolittle)":mailto:jimdo@ + example.com + + The following is an example of this property with "delegatee" and + "delegator" information for an event: + + ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE;DELEGATED-FROM= + "mailto:iamboss@example.com";CN=Henry Cabot:mailto:hcabot@ + example.com + ATTENDEE;ROLE=NON-PARTICIPANT;PARTSTAT=DELEGATED;DELEGATED-TO= + "mailto:hcabot@example.com";CN=The Big Cheese:mailto:iamboss + @example.com + ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;CN=Jane Doe + :mailto:jdoe@example.com + + Example: The following is an example of this property's use when + another calendar user is acting on behalf of the "Attendee": + + ATTENDEE;SENT-BY=mailto:jan_doe@example.com;CN=John Smith: + mailto:jsmith@example.com + +3.8.4.2. Contact + + Property Name: CONTACT + + Purpose: This property is used to represent contact information or + alternately a reference to contact information associated with the + calendar component. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, alternate text + representation, and language property parameters can be specified + on this property. + + + + +Desruisseaux Standards Track [Page 109] + +RFC 5545 iCalendar September 2009 + + + Conformance: This property can be specified in a "VEVENT", "VTODO", + "VJOURNAL", or "VFREEBUSY" calendar component. + + Description: The property value consists of textual contact + information. An alternative representation for the property value + can also be specified that refers to a URI pointing to an + alternate form, such as a vCard [RFC2426], for the contact + information. + + Format Definition: This property is defined by the following + notation: + + contact = "CONTACT" contparam ":" text CRLF + + contparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" altrepparam) / (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following is an example of this property referencing + textual contact information: + + CONTACT:Jim Dolittle\, ABC Industries\, +1-919-555-1234 + + The following is an example of this property with an alternate + representation of an LDAP URI to a directory entry containing the + contact information: + + CONTACT;ALTREP="ldap://example.com:6666/o=ABC%20Industries\, + c=US???(cn=Jim%20Dolittle)":Jim Dolittle\, ABC Industries\, + +1-919-555-1234 + + The following is an example of this property with an alternate + representation of a MIME body part containing the contact + information, such as a vCard [RFC2426] embedded in a text/ + directory media type [RFC2425]: + + CONTACT;ALTREP="CID:part3.msg970930T083000SILVER@example.com": + Jim Dolittle\, ABC Industries\, +1-919-555-1234 + + + +Desruisseaux Standards Track [Page 110] + +RFC 5545 iCalendar September 2009 + + + The following is an example of this property referencing a network + resource, such as a vCard [RFC2426] object containing the contact + information: + + CONTACT;ALTREP="http://example.com/pdi/jdoe.vcf":Jim + Dolittle\, ABC Industries\, +1-919-555-1234 + +3.8.4.3. Organizer + + Property Name: ORGANIZER + + Purpose: This property defines the organizer for a calendar + component. + + Value Type: CAL-ADDRESS + + Property Parameters: IANA, non-standard, language, common name, + directory entry reference, and sent-by property parameters can be + specified on this property. + + Conformance: This property MUST be specified in an iCalendar object + that specifies a group-scheduled calendar entity. This property + MUST be specified in an iCalendar object that specifies the + publication of a calendar user's busy time. This property MUST + NOT be specified in an iCalendar object that specifies only a time + zone definition or that defines calendar components that are not + group-scheduled components, but are components only on a single + user's calendar. + + Description: This property is specified within the "VEVENT", + "VTODO", and "VJOURNAL" calendar components to specify the + organizer of a group-scheduled calendar entity. The property is + specified within the "VFREEBUSY" calendar component to specify the + calendar user requesting the free or busy time. When publishing a + "VFREEBUSY" calendar component, the property is used to specify + the calendar that the published busy time came from. + + The property has the property parameters "CN", for specifying the + common or display name associated with the "Organizer", "DIR", for + specifying a pointer to the directory information associated with + the "Organizer", "SENT-BY", for specifying another calendar user + that is acting on behalf of the "Organizer". The non-standard + parameters may also be specified on this property. If the + "LANGUAGE" property parameter is specified, the identified + language applies to the "CN" parameter value. + + + + + + +Desruisseaux Standards Track [Page 111] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This property is defined by the following + notation: + + organizer = "ORGANIZER" orgparam ":" + cal-address CRLF + + orgparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" cnparam) / (";" dirparam) / (";" sentbyparam) / + (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + Example: The following is an example of this property: + + ORGANIZER;CN=John Smith:mailto:jsmith@example.com + + The following is an example of this property with a pointer to the + directory information associated with the organizer: + + ORGANIZER;CN=JohnSmith;DIR="ldap://example.com:6666/o=DC%20Ass + ociates,c=US???(cn=John%20Smith)":mailto:jsmith@example.com + + The following is an example of this property used by another + calendar user who is acting on behalf of the organizer, with + responses intended to be sent back to the organizer, not the other + calendar user: + + ORGANIZER;SENT-BY="mailto:jane_doe@example.com": + mailto:jsmith@example.com + +3.8.4.4. Recurrence ID + + Property Name: RECURRENCE-ID + + Purpose: This property is used in conjunction with the "UID" and + "SEQUENCE" properties to identify a specific instance of a + recurring "VEVENT", "VTODO", or "VJOURNAL" calendar component. + The property value is the original value of the "DTSTART" property + of the recurrence instance. + + + +Desruisseaux Standards Track [Page 112] + +RFC 5545 iCalendar September 2009 + + + Value Type: The default value type is DATE-TIME. The value type can + be set to a DATE value type. This property MUST have the same + value type as the "DTSTART" property contained within the + recurring component. Furthermore, this property MUST be specified + as a date with local time if and only if the "DTSTART" property + contained within the recurring component is specified as a date + with local time. + + Property Parameters: IANA, non-standard, value data type, time zone + identifier, and recurrence identifier range parameters can be + specified on this property. + + Conformance: This property can be specified in an iCalendar object + containing a recurring calendar component. + + Description: The full range of calendar components specified by a + recurrence set is referenced by referring to just the "UID" + property value corresponding to the calendar component. The + "RECURRENCE-ID" property allows the reference to an individual + instance within the recurrence set. + + If the value of the "DTSTART" property is a DATE type value, then + the value MUST be the calendar date for the recurrence instance. + + The DATE-TIME value is set to the time when the original + recurrence instance would occur; meaning that if the intent is to + change a Friday meeting to Thursday, the DATE-TIME is still set to + the original Friday meeting. + + The "RECURRENCE-ID" property is used in conjunction with the "UID" + and "SEQUENCE" properties to identify a particular instance of a + recurring event, to-do, or journal. For a given pair of "UID" and + "SEQUENCE" property values, the "RECURRENCE-ID" value for a + recurrence instance is fixed. + + The "RANGE" parameter is used to specify the effective range of + recurrence instances from the instance specified by the + "RECURRENCE-ID" property value. The value for the range parameter + can only be "THISANDFUTURE" to indicate a range defined by the + given recurrence instance and all subsequent instances. + Subsequent instances are determined by their "RECURRENCE-ID" value + and not their current scheduled start time. Subsequent instances + defined in separate components are not impacted by the given + recurrence instance. When the given recurrence instance is + rescheduled, all subsequent instances are also rescheduled by the + same time difference. For instance, if the given recurrence + instance is rescheduled to start 2 hours later, then all + subsequent instances are also rescheduled 2 hours later. + + + +Desruisseaux Standards Track [Page 113] + +RFC 5545 iCalendar September 2009 + + + Similarly, if the duration of the given recurrence instance is + modified, then all subsequence instances are also modified to have + this same duration. + + Note: The "RANGE" parameter may not be appropriate to + reschedule specific subsequent instances of complex recurring + calendar component. Assuming an unbounded recurring calendar + component scheduled to occur on Mondays and Wednesdays, the + "RANGE" parameter could not be used to reschedule only the + future Monday instances to occur on Tuesday instead. In such + cases, the calendar application could simply truncate the + unbounded recurring calendar component (i.e., with the "COUNT" + or "UNTIL" rule parts), and create two new unbounded recurring + calendar components for the future instances. + + Format Definition: This property is defined by the following + notation: + + recurid = "RECURRENCE-ID" ridparam ":" ridval CRLF + + ridparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / + (";" tzidparam) / (";" rangeparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + ridval = date-time / date + ;Value MUST match value type + + Example: The following are examples of this property: + + RECURRENCE-ID;VALUE=DATE:19960401 + + RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z + + + + + + + + +Desruisseaux Standards Track [Page 114] + +RFC 5545 iCalendar September 2009 + + +3.8.4.5. Related To + + Property Name: RELATED-TO + + Purpose: This property is used to represent a relationship or + reference between one calendar component and another. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, and relationship type + property parameters can be specified on this property. + + Conformance: This property can be specified in the "VEVENT", + "VTODO", and "VJOURNAL" calendar components. + + Description: The property value consists of the persistent, globally + unique identifier of another calendar component. This value would + be represented in a calendar component by the "UID" property. + + By default, the property value points to another calendar + component that has a PARENT relationship to the referencing + object. The "RELTYPE" property parameter is used to either + explicitly state the default PARENT relationship type to the + referenced calendar component or to override the default PARENT + relationship type and specify either a CHILD or SIBLING + relationship. The PARENT relationship indicates that the calendar + component is a subordinate of the referenced calendar component. + The CHILD relationship indicates that the calendar component is a + superior of the referenced calendar component. The SIBLING + relationship indicates that the calendar component is a peer of + the referenced calendar component. + + Changes to a calendar component referenced by this property can + have an implicit impact on the related calendar component. For + example, if a group event changes its start or end date or time, + then the related, dependent events will need to have their start + and end dates changed in a corresponding way. Similarly, if a + PARENT calendar component is cancelled or deleted, then there is + an implied impact to the related CHILD calendar components. This + property is intended only to provide information on the + relationship of calendar components. It is up to the target + calendar system to maintain any property implications of this + relationship. + + + + + + + + +Desruisseaux Standards Track [Page 115] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This property is defined by the following + notation: + + related = "RELATED-TO" relparam ":" text CRLF + + relparam = *( + ; + ; The following is OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" reltypeparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + The following is an example of this property: + + RELATED-TO:jsmith.part7.19960817T083000.xyzMail@example.com + + RELATED-TO:19960401-080045-4000F192713-0052@example.com + +3.8.4.6. Uniform Resource Locator + + Property Name: URL + + Purpose: This property defines a Uniform Resource Locator (URL) + associated with the iCalendar object. + + Value Type: URI + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified once in the "VEVENT", + "VTODO", "VJOURNAL", or "VFREEBUSY" calendar components. + + Description: This property may be used in a calendar component to + convey a location where a more dynamic rendition of the calendar + information associated with the calendar component can be found. + This memo does not attempt to standardize the form of the URI, nor + the format of the resource pointed to by the property value. If + the URL property and Content-Location MIME header are both + specified, they MUST point to the same resource. + + + + +Desruisseaux Standards Track [Page 116] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This property is defined by the following + notation: + + url = "URL" urlparam ":" uri CRLF + + urlparam = *(";" other-param) + + Example: The following is an example of this property: + + URL:http://example.com/pub/calendars/jsmith/mytime.ics + +3.8.4.7. Unique Identifier + + Property Name: UID + + Purpose: This property defines the persistent, globally unique + identifier for the calendar component. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: The property MUST be specified in the "VEVENT", + "VTODO", "VJOURNAL", or "VFREEBUSY" calendar components. + + Description: The "UID" itself MUST be a globally unique identifier. + The generator of the identifier MUST guarantee that the identifier + is unique. There are several algorithms that can be used to + accomplish this. A good method to assure uniqueness is to put the + domain name or a domain literal IP address of the host on which + the identifier was created on the right-hand side of an "@", and + on the left-hand side, put a combination of the current calendar + date and time of day (i.e., formatted in as a DATE-TIME value) + along with some other currently unique (perhaps sequential) + identifier available on the system (for example, a process id + number). Using a DATE-TIME value on the left-hand side and a + domain name or domain literal on the right-hand side makes it + possible to guarantee uniqueness since no two hosts should be + using the same domain name or IP address at the same time. Though + other algorithms will work, it is RECOMMENDED that the right-hand + side contain some domain identifier (either of the host itself or + otherwise) such that the generator of the message identifier can + guarantee the uniqueness of the left-hand side within the scope of + that domain. + + This is the method for correlating scheduling messages with the + referenced "VEVENT", "VTODO", or "VJOURNAL" calendar component. + + + +Desruisseaux Standards Track [Page 117] + +RFC 5545 iCalendar September 2009 + + + The full range of calendar components specified by a recurrence + set is referenced by referring to just the "UID" property value + corresponding to the calendar component. The "RECURRENCE-ID" + property allows the reference to an individual instance within the + recurrence set. + + This property is an important method for group-scheduling + applications to match requests with later replies, modifications, + or deletion requests. Calendaring and scheduling applications + MUST generate this property in "VEVENT", "VTODO", and "VJOURNAL" + calendar components to assure interoperability with other group- + scheduling applications. This identifier is created by the + calendar system that generates an iCalendar object. + + Implementations MUST be able to receive and persist values of at + least 255 octets for this property, but they MUST NOT truncate + values in the middle of a UTF-8 multi-octet sequence. + + Format Definition: This property is defined by the following + notation: + + uid = "UID" uidparam ":" text CRLF + + uidparam = *(";" other-param) + + Example: The following is an example of this property: + + UID:19960401T080045Z-4000F192713-0052@example.com + +3.8.5. Recurrence Component Properties + + The following properties specify recurrence information in calendar + components. + +3.8.5.1. Exception Date-Times + + Property Name: EXDATE + + Purpose: This property defines the list of DATE-TIME exceptions for + recurring events, to-dos, journal entries, or time zone + definitions. + + Value Type: The default value type for this property is DATE-TIME. + The value type can be set to DATE. + + Property Parameters: IANA, non-standard, value data type, and time + zone identifier property parameters can be specified on this + property. + + + +Desruisseaux Standards Track [Page 118] + +RFC 5545 iCalendar September 2009 + + + Conformance: This property can be specified in recurring "VEVENT", + "VTODO", and "VJOURNAL" calendar components as well as in the + "STANDARD" and "DAYLIGHT" sub-components of the "VTIMEZONE" + calendar component. + + Description: The exception dates, if specified, are used in + computing the recurrence set. The recurrence set is the complete + set of recurrence instances for a calendar component. The + recurrence set is generated by considering the initial "DTSTART" + property along with the "RRULE", "RDATE", and "EXDATE" properties + contained within the recurring component. The "DTSTART" property + defines the first instance in the recurrence set. The "DTSTART" + property value SHOULD match the pattern of the recurrence rule, if + specified. The recurrence set generated with a "DTSTART" property + value that doesn't match the pattern of the rule is undefined. + The final recurrence set is generated by gathering all of the + start DATE-TIME values generated by any of the specified "RRULE" + and "RDATE" properties, and then excluding any start DATE-TIME + values specified by "EXDATE" properties. This implies that start + DATE-TIME values specified by "EXDATE" properties take precedence + over those specified by inclusion properties (i.e., "RDATE" and + "RRULE"). When duplicate instances are generated by the "RRULE" + and "RDATE" properties, only one recurrence is considered. + Duplicate instances are ignored. + + The "EXDATE" property can be used to exclude the value specified + in "DTSTART". However, in such cases, the original "DTSTART" date + MUST still be maintained by the calendaring and scheduling system + because the original "DTSTART" value has inherent usage + dependencies by other properties such as the "RECURRENCE-ID". + + Format Definition: This property is defined by the following + notation: + + + + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 119] + +RFC 5545 iCalendar September 2009 + + + exdate = "EXDATE" exdtparam ":" exdtval *("," exdtval) CRLF + + exdtparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" "VALUE" "=" ("DATE-TIME" / "DATE")) / + ; + (";" tzidparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + exdtval = date-time / date + ;Value MUST match value type + + Example: The following is an example of this property: + + EXDATE:19960402T010000Z,19960403T010000Z,19960404T010000Z + +3.8.5.2. Recurrence Date-Times + + Property Name: RDATE + + Purpose: This property defines the list of DATE-TIME values for + recurring events, to-dos, journal entries, or time zone + definitions. + + Value Type: The default value type for this property is DATE-TIME. + The value type can be set to DATE or PERIOD. + + Property Parameters: IANA, non-standard, value data type, and time + zone identifier property parameters can be specified on this + property. + + Conformance: This property can be specified in recurring "VEVENT", + "VTODO", and "VJOURNAL" calendar components as well as in the + "STANDARD" and "DAYLIGHT" sub-components of the "VTIMEZONE" + calendar component. + + Description: This property can appear along with the "RRULE" + property to define an aggregate set of repeating occurrences. + When they both appear in a recurring component, the recurrence + + + +Desruisseaux Standards Track [Page 120] + +RFC 5545 iCalendar September 2009 + + + instances are defined by the union of occurrences defined by both + the "RDATE" and "RRULE". + + The recurrence dates, if specified, are used in computing the + recurrence set. The recurrence set is the complete set of + recurrence instances for a calendar component. The recurrence set + is generated by considering the initial "DTSTART" property along + with the "RRULE", "RDATE", and "EXDATE" properties contained + within the recurring component. The "DTSTART" property defines + the first instance in the recurrence set. The "DTSTART" property + value SHOULD match the pattern of the recurrence rule, if + specified. The recurrence set generated with a "DTSTART" property + value that doesn't match the pattern of the rule is undefined. + The final recurrence set is generated by gathering all of the + start DATE-TIME values generated by any of the specified "RRULE" + and "RDATE" properties, and then excluding any start DATE-TIME + values specified by "EXDATE" properties. This implies that start + DATE-TIME values specified by "EXDATE" properties take precedence + over those specified by inclusion properties (i.e., "RDATE" and + "RRULE"). Where duplicate instances are generated by the "RRULE" + and "RDATE" properties, only one recurrence is considered. + Duplicate instances are ignored. + + Format Definition: This property is defined by the following + notation: + + rdate = "RDATE" rdtparam ":" rdtval *("," rdtval) CRLF + + rdtparam = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" "VALUE" "=" ("DATE-TIME" / "DATE" / "PERIOD")) / + (";" tzidparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + rdtval = date-time / date / period + ;Value MUST match value type + + + + + + +Desruisseaux Standards Track [Page 121] + +RFC 5545 iCalendar September 2009 + + + Example: The following are examples of this property: + + RDATE:19970714T123000Z + RDATE;TZID=America/New_York:19970714T083000 + + RDATE;VALUE=PERIOD:19960403T020000Z/19960403T040000Z, + 19960404T010000Z/PT3H + + RDATE;VALUE=DATE:19970101,19970120,19970217,19970421 + 19970526,19970704,19970901,19971014,19971128,19971129,19971225 + +3.8.5.3. Recurrence Rule + + Property Name: RRULE + + Purpose: This property defines a rule or repeating pattern for + recurring events, to-dos, journal entries, or time zone + definitions. + + Value Type: RECUR + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified in recurring "VEVENT", + "VTODO", and "VJOURNAL" calendar components as well as in the + "STANDARD" and "DAYLIGHT" sub-components of the "VTIMEZONE" + calendar component, but it SHOULD NOT be specified more than once. + The recurrence set generated with multiple "RRULE" properties is + undefined. + + Description: The recurrence rule, if specified, is used in computing + the recurrence set. The recurrence set is the complete set of + recurrence instances for a calendar component. The recurrence set + is generated by considering the initial "DTSTART" property along + with the "RRULE", "RDATE", and "EXDATE" properties contained + within the recurring component. The "DTSTART" property defines + the first instance in the recurrence set. The "DTSTART" property + value SHOULD be synchronized with the recurrence rule, if + specified. The recurrence set generated with a "DTSTART" property + value not synchronized with the recurrence rule is undefined. The + final recurrence set is generated by gathering all of the start + DATE-TIME values generated by any of the specified "RRULE" and + "RDATE" properties, and then excluding any start DATE-TIME values + specified by "EXDATE" properties. This implies that start DATE- + TIME values specified by "EXDATE" properties take precedence over + those specified by inclusion properties (i.e., "RDATE" and + "RRULE"). Where duplicate instances are generated by the "RRULE" + + + +Desruisseaux Standards Track [Page 122] + +RFC 5545 iCalendar September 2009 + + + and "RDATE" properties, only one recurrence is considered. + Duplicate instances are ignored. + + The "DTSTART" property specified within the iCalendar object + defines the first instance of the recurrence. In most cases, a + "DTSTART" property of DATE-TIME value type used with a recurrence + rule, should be specified as a date with local time and time zone + reference to make sure all the recurrence instances start at the + same local time regardless of time zone changes. + + If the duration of the recurring component is specified with the + "DTEND" or "DUE" property, then the same exact duration will apply + to all the members of the generated recurrence set. Else, if the + duration of the recurring component is specified with the + "DURATION" property, then the same nominal duration will apply to + all the members of the generated recurrence set and the exact + duration of each recurrence instance will depend on its specific + start time. For example, recurrence instances of a nominal + duration of one day will have an exact duration of more or less + than 24 hours on a day where a time zone shift occurs. The + duration of a specific recurrence may be modified in an exception + component or simply by using an "RDATE" property of PERIOD value + type. + + Format Definition: This property is defined by the following + notation: + + rrule = "RRULE" rrulparam ":" recur CRLF + + rrulparam = *(";" other-param) + + Example: All examples assume the Eastern United States time zone. + + Daily for 10 occurrences: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=DAILY;COUNT=10 + + ==> (1997 9:00 AM EDT) September 2-11 + + Daily until December 24, 1997: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=DAILY;UNTIL=19971224T000000Z + + ==> (1997 9:00 AM EDT) September 2-30;October 1-25 + (1997 9:00 AM EST) October 26-31;November 1-30;December 1-23 + + + + +Desruisseaux Standards Track [Page 123] + +RFC 5545 iCalendar September 2009 + + + Every other day - forever: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=DAILY;INTERVAL=2 + + ==> (1997 9:00 AM EDT) September 2,4,6,8...24,26,28,30; + October 2,4,6...20,22,24 + (1997 9:00 AM EST) October 26,28,30; + November 1,3,5,7...25,27,29; + December 1,3,... + + Every 10 days, 5 occurrences: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=DAILY;INTERVAL=10;COUNT=5 + + ==> (1997 9:00 AM EDT) September 2,12,22; + October 2,12 + + Every day in January, for 3 years: + + DTSTART;TZID=America/New_York:19980101T090000 + + RRULE:FREQ=YEARLY;UNTIL=20000131T140000Z; + BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA + or + RRULE:FREQ=DAILY;UNTIL=20000131T140000Z;BYMONTH=1 + + ==> (1998 9:00 AM EST)January 1-31 + (1999 9:00 AM EST)January 1-31 + (2000 9:00 AM EST)January 1-31 + + Weekly for 10 occurrences: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=WEEKLY;COUNT=10 + + ==> (1997 9:00 AM EDT) September 2,9,16,23,30;October 7,14,21 + (1997 9:00 AM EST) October 28;November 4 + + + + + + + + + + + + +Desruisseaux Standards Track [Page 124] + +RFC 5545 iCalendar September 2009 + + + Weekly until December 24, 1997: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=WEEKLY;UNTIL=19971224T000000Z + + ==> (1997 9:00 AM EDT) September 2,9,16,23,30; + October 7,14,21 + (1997 9:00 AM EST) October 28; + November 4,11,18,25; + December 2,9,16,23 + + Every other week - forever: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=WEEKLY;INTERVAL=2;WKST=SU + + ==> (1997 9:00 AM EDT) September 2,16,30; + October 14 + (1997 9:00 AM EST) October 28; + November 11,25; + December 9,23 + (1998 9:00 AM EST) January 6,20; + February 3, 17 + ... + + Weekly on Tuesday and Thursday for five weeks: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=WEEKLY;UNTIL=19971007T000000Z;WKST=SU;BYDAY=TU,TH + + or + + RRULE:FREQ=WEEKLY;COUNT=10;WKST=SU;BYDAY=TU,TH + + ==> (1997 9:00 AM EDT) September 2,4,9,11,16,18,23,25,30; + October 2 + + Every other week on Monday, Wednesday, and Friday until December + 24, 1997, starting on Monday, September 1, 1997: + + DTSTART;TZID=America/New_York:19970901T090000 + RRULE:FREQ=WEEKLY;INTERVAL=2;UNTIL=19971224T000000Z;WKST=SU; + BYDAY=MO,WE,FR + + ==> (1997 9:00 AM EDT) September 1,3,5,15,17,19,29; + October 1,3,13,15,17 + (1997 9:00 AM EST) October 27,29,31; + November 10,12,14,24,26,28; + + + +Desruisseaux Standards Track [Page 125] + +RFC 5545 iCalendar September 2009 + + + December 8,10,12,22 + + Every other week on Tuesday and Thursday, for 8 occurrences: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=8;WKST=SU;BYDAY=TU,TH + + ==> (1997 9:00 AM EDT) September 2,4,16,18,30; + October 2,14,16 + + Monthly on the first Friday for 10 occurrences: + + DTSTART;TZID=America/New_York:19970905T090000 + RRULE:FREQ=MONTHLY;COUNT=10;BYDAY=1FR + + ==> (1997 9:00 AM EDT) September 5;October 3 + (1997 9:00 AM EST) November 7;December 5 + (1998 9:00 AM EST) January 2;February 6;March 6;April 3 + (1998 9:00 AM EDT) May 1;June 5 + + Monthly on the first Friday until December 24, 1997: + + DTSTART;TZID=America/New_York:19970905T090000 + RRULE:FREQ=MONTHLY;UNTIL=19971224T000000Z;BYDAY=1FR + + ==> (1997 9:00 AM EDT) September 5; October 3 + (1997 9:00 AM EST) November 7; December 5 + + Every other month on the first and last Sunday of the month for 10 + occurrences: + + DTSTART;TZID=America/New_York:19970907T090000 + RRULE:FREQ=MONTHLY;INTERVAL=2;COUNT=10;BYDAY=1SU,-1SU + + ==> (1997 9:00 AM EDT) September 7,28 + (1997 9:00 AM EST) November 2,30 + (1998 9:00 AM EST) January 4,25;March 1,29 + (1998 9:00 AM EDT) May 3,31 + + Monthly on the second-to-last Monday of the month for 6 months: + + DTSTART;TZID=America/New_York:19970922T090000 + RRULE:FREQ=MONTHLY;COUNT=6;BYDAY=-2MO + + ==> (1997 9:00 AM EDT) September 22;October 20 + (1997 9:00 AM EST) November 17;December 22 + (1998 9:00 AM EST) January 19;February 16 + + + + +Desruisseaux Standards Track [Page 126] + +RFC 5545 iCalendar September 2009 + + + Monthly on the third-to-the-last day of the month, forever: + + DTSTART;TZID=America/New_York:19970928T090000 + RRULE:FREQ=MONTHLY;BYMONTHDAY=-3 + + ==> (1997 9:00 AM EDT) September 28 + (1997 9:00 AM EST) October 29;November 28;December 29 + (1998 9:00 AM EST) January 29;February 26 + ... + + Monthly on the 2nd and 15th of the month for 10 occurrences: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=2,15 + + ==> (1997 9:00 AM EDT) September 2,15;October 2,15 + (1997 9:00 AM EST) November 2,15;December 2,15 + (1998 9:00 AM EST) January 2,15 + + Monthly on the first and last day of the month for 10 occurrences: + + DTSTART;TZID=America/New_York:19970930T090000 + RRULE:FREQ=MONTHLY;COUNT=10;BYMONTHDAY=1,-1 + + ==> (1997 9:00 AM EDT) September 30;October 1 + (1997 9:00 AM EST) October 31;November 1,30;December 1,31 + (1998 9:00 AM EST) January 1,31;February 1 + + Every 18 months on the 10th thru 15th of the month for 10 + occurrences: + + DTSTART;TZID=America/New_York:19970910T090000 + RRULE:FREQ=MONTHLY;INTERVAL=18;COUNT=10;BYMONTHDAY=10,11,12, + 13,14,15 + + ==> (1997 9:00 AM EDT) September 10,11,12,13,14,15 + (1999 9:00 AM EST) March 10,11,12,13 + + Every Tuesday, every other month: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=MONTHLY;INTERVAL=2;BYDAY=TU + + ==> (1997 9:00 AM EDT) September 2,9,16,23,30 + (1997 9:00 AM EST) November 4,11,18,25 + (1998 9:00 AM EST) January 6,13,20,27;March 3,10,17,24,31 + ... + + + + +Desruisseaux Standards Track [Page 127] + +RFC 5545 iCalendar September 2009 + + + Yearly in June and July for 10 occurrences: + + DTSTART;TZID=America/New_York:19970610T090000 + RRULE:FREQ=YEARLY;COUNT=10;BYMONTH=6,7 + + ==> (1997 9:00 AM EDT) June 10;July 10 + (1998 9:00 AM EDT) June 10;July 10 + (1999 9:00 AM EDT) June 10;July 10 + (2000 9:00 AM EDT) June 10;July 10 + (2001 9:00 AM EDT) June 10;July 10 + + Note: Since none of the BYDAY, BYMONTHDAY, or BYYEARDAY + components are specified, the day is gotten from "DTSTART". + + Every other year on January, February, and March for 10 + occurrences: + + DTSTART;TZID=America/New_York:19970310T090000 + RRULE:FREQ=YEARLY;INTERVAL=2;COUNT=10;BYMONTH=1,2,3 + + ==> (1997 9:00 AM EST) March 10 + (1999 9:00 AM EST) January 10;February 10;March 10 + (2001 9:00 AM EST) January 10;February 10;March 10 + (2003 9:00 AM EST) January 10;February 10;March 10 + + Every third year on the 1st, 100th, and 200th day for 10 + occurrences: + + DTSTART;TZID=America/New_York:19970101T090000 + RRULE:FREQ=YEARLY;INTERVAL=3;COUNT=10;BYYEARDAY=1,100,200 + + ==> (1997 9:00 AM EST) January 1 + (1997 9:00 AM EDT) April 10;July 19 + (2000 9:00 AM EST) January 1 + (2000 9:00 AM EDT) April 9;July 18 + (2003 9:00 AM EST) January 1 + (2003 9:00 AM EDT) April 10;July 19 + (2006 9:00 AM EST) January 1 + + Every 20th Monday of the year, forever: + + DTSTART;TZID=America/New_York:19970519T090000 + RRULE:FREQ=YEARLY;BYDAY=20MO + + ==> (1997 9:00 AM EDT) May 19 + (1998 9:00 AM EDT) May 18 + (1999 9:00 AM EDT) May 17 + ... + + + +Desruisseaux Standards Track [Page 128] + +RFC 5545 iCalendar September 2009 + + + Monday of week number 20 (where the default start of the week is + Monday), forever: + + DTSTART;TZID=America/New_York:19970512T090000 + RRULE:FREQ=YEARLY;BYWEEKNO=20;BYDAY=MO + + ==> (1997 9:00 AM EDT) May 12 + (1998 9:00 AM EDT) May 11 + (1999 9:00 AM EDT) May 17 + ... + + Every Thursday in March, forever: + + DTSTART;TZID=America/New_York:19970313T090000 + RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=TH + + ==> (1997 9:00 AM EST) March 13,20,27 + (1998 9:00 AM EST) March 5,12,19,26 + (1999 9:00 AM EST) March 4,11,18,25 + ... + + Every Thursday, but only during June, July, and August, forever: + + DTSTART;TZID=America/New_York:19970605T090000 + RRULE:FREQ=YEARLY;BYDAY=TH;BYMONTH=6,7,8 + + ==> (1997 9:00 AM EDT) June 5,12,19,26;July 3,10,17,24,31; + August 7,14,21,28 + (1998 9:00 AM EDT) June 4,11,18,25;July 2,9,16,23,30; + August 6,13,20,27 + (1999 9:00 AM EDT) June 3,10,17,24;July 1,8,15,22,29; + August 5,12,19,26 + ... + + Every Friday the 13th, forever: + + DTSTART;TZID=America/New_York:19970902T090000 + EXDATE;TZID=America/New_York:19970902T090000 + RRULE:FREQ=MONTHLY;BYDAY=FR;BYMONTHDAY=13 + + ==> (1998 9:00 AM EST) February 13;March 13;November 13 + (1999 9:00 AM EDT) August 13 + (2000 9:00 AM EDT) October 13 + ... + + + + + + + +Desruisseaux Standards Track [Page 129] + +RFC 5545 iCalendar September 2009 + + + The first Saturday that follows the first Sunday of the month, + forever: + + DTSTART;TZID=America/New_York:19970913T090000 + RRULE:FREQ=MONTHLY;BYDAY=SA;BYMONTHDAY=7,8,9,10,11,12,13 + + ==> (1997 9:00 AM EDT) September 13;October 11 + (1997 9:00 AM EST) November 8;December 13 + (1998 9:00 AM EST) January 10;February 7;March 7 + (1998 9:00 AM EDT) April 11;May 9;June 13... + ... + + Every 4 years, the first Tuesday after a Monday in November, + forever (U.S. Presidential Election day): + + DTSTART;TZID=America/New_York:19961105T090000 + RRULE:FREQ=YEARLY;INTERVAL=4;BYMONTH=11;BYDAY=TU; + BYMONTHDAY=2,3,4,5,6,7,8 + + ==> (1996 9:00 AM EST) November 5 + (2000 9:00 AM EST) November 7 + (2004 9:00 AM EST) November 2 + ... + + The third instance into the month of one of Tuesday, Wednesday, or + Thursday, for the next 3 months: + + DTSTART;TZID=America/New_York:19970904T090000 + RRULE:FREQ=MONTHLY;COUNT=3;BYDAY=TU,WE,TH;BYSETPOS=3 + + ==> (1997 9:00 AM EDT) September 4;October 7 + (1997 9:00 AM EST) November 6 + + The second-to-last weekday of the month: + + DTSTART;TZID=America/New_York:19970929T090000 + RRULE:FREQ=MONTHLY;BYDAY=MO,TU,WE,TH,FR;BYSETPOS=-2 + + ==> (1997 9:00 AM EDT) September 29 + (1997 9:00 AM EST) October 30;November 27;December 30 + (1998 9:00 AM EST) January 29;February 26;March 30 + ... + + + + + + + + + +Desruisseaux Standards Track [Page 130] + +RFC 5545 iCalendar September 2009 + + + Every 3 hours from 9:00 AM to 5:00 PM on a specific day: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=HOURLY;INTERVAL=3;UNTIL=19970902T170000Z + + ==> (September 2, 1997 EDT) 09:00,12:00,15:00 + + Every 15 minutes for 6 occurrences: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=MINUTELY;INTERVAL=15;COUNT=6 + + ==> (September 2, 1997 EDT) 09:00,09:15,09:30,09:45,10:00,10:15 + + Every hour and a half for 4 occurrences: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=MINUTELY;INTERVAL=90;COUNT=4 + + ==> (September 2, 1997 EDT) 09:00,10:30;12:00;13:30 + + Every 20 minutes from 9:00 AM to 4:40 PM every day: + + DTSTART;TZID=America/New_York:19970902T090000 + RRULE:FREQ=DAILY;BYHOUR=9,10,11,12,13,14,15,16;BYMINUTE=0,20,40 + or + RRULE:FREQ=MINUTELY;INTERVAL=20;BYHOUR=9,10,11,12,13,14,15,16 + + ==> (September 2, 1997 EDT) 9:00,9:20,9:40,10:00,10:20, + ... 16:00,16:20,16:40 + (September 3, 1997 EDT) 9:00,9:20,9:40,10:00,10:20, + ...16:00,16:20,16:40 + ... + + An example where the days generated makes a difference because of + WKST: + + DTSTART;TZID=America/New_York:19970805T090000 + RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=MO + + ==> (1997 EDT) August 5,10,19,24 + + changing only WKST from MO to SU, yields different results... + + DTSTART;TZID=America/New_York:19970805T090000 + RRULE:FREQ=WEEKLY;INTERVAL=2;COUNT=4;BYDAY=TU,SU;WKST=SU + + ==> (1997 EDT) August 5,17,19,31 + + + +Desruisseaux Standards Track [Page 131] + +RFC 5545 iCalendar September 2009 + + + An example where an invalid date (i.e., February 30) is ignored. + + DTSTART;TZID=America/New_York:20070115T090000 + RRULE:FREQ=MONTHLY;BYMONTHDAY=15,30;COUNT=5 + + ==> (2007 EST) January 15,30 + (2007 EST) February 15 + (2007 EDT) March 15,30 + +3.8.6. Alarm Component Properties + + The following properties specify alarm information in calendar + components. + +3.8.6.1. Action + + Property Name: ACTION + + Purpose: This property defines the action to be invoked when an + alarm is triggered. + + Value Type: TEXT + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property MUST be specified once in a "VALARM" + calendar component. + + Description: Each "VALARM" calendar component has a particular type + of action with which it is associated. This property specifies + the type of action. Applications MUST ignore alarms with x-name + and iana-token values they don't recognize. + + Format Definition: This property is defined by the following + notation: + + action = "ACTION" actionparam ":" actionvalue CRLF + + actionparam = *(";" other-param) + + + actionvalue = "AUDIO" / "DISPLAY" / "EMAIL" + / iana-token / x-name + + Example: The following are examples of this property in a "VALARM" + calendar component: + + + + +Desruisseaux Standards Track [Page 132] + +RFC 5545 iCalendar September 2009 + + + ACTION:AUDIO + + ACTION:DISPLAY + +3.8.6.2. Repeat Count + + Property Name: REPEAT + + Purpose: This property defines the number of times the alarm should + be repeated, after the initial trigger. + + Value Type: INTEGER + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified in a "VALARM" calendar + component. + + Description: This property defines the number of times an alarm + should be repeated after its initial trigger. If the alarm + triggers more than once, then this property MUST be specified + along with the "DURATION" property. + + Format Definition: This property is defined by the following + notation: + + repeat = "REPEAT" repparam ":" integer CRLF + ;Default is "0", zero. + + repparam = *(";" other-param) + + Example: The following is an example of this property for an alarm + that repeats 4 additional times with a 5-minute delay after the + initial triggering of the alarm: + + REPEAT:4 + DURATION:PT5M + +3.8.6.3. Trigger + + Property Name: TRIGGER + + Purpose: This property specifies when an alarm will trigger. + + Value Type: The default value type is DURATION. The value type can + be set to a DATE-TIME value type, in which case the value MUST + specify a UTC-formatted DATE-TIME value. + + + +Desruisseaux Standards Track [Page 133] + +RFC 5545 iCalendar September 2009 + + + Property Parameters: IANA, non-standard, value data type, time zone + identifier, or trigger relationship property parameters can be + specified on this property. The trigger relationship property + parameter MUST only be specified when the value type is + "DURATION". + + Conformance: This property MUST be specified in the "VALARM" + calendar component. + + Description: This property defines when an alarm will trigger. The + default value type is DURATION, specifying a relative time for the + trigger of the alarm. The default duration is relative to the + start of an event or to-do with which the alarm is associated. + The duration can be explicitly set to trigger from either the end + or the start of the associated event or to-do with the "RELATED" + parameter. A value of START will set the alarm to trigger off the + start of the associated event or to-do. A value of END will set + the alarm to trigger off the end of the associated event or to-do. + + Either a positive or negative duration may be specified for the + "TRIGGER" property. An alarm with a positive duration is + triggered after the associated start or end of the event or to-do. + An alarm with a negative duration is triggered before the + associated start or end of the event or to-do. + + The "RELATED" property parameter is not valid if the value type of + the property is set to DATE-TIME (i.e., for an absolute date and + time alarm trigger). If a value type of DATE-TIME is specified, + then the property value MUST be specified in the UTC time format. + If an absolute trigger is specified on an alarm for a recurring + event or to-do, then the alarm will only trigger for the specified + absolute DATE-TIME, along with any specified repeating instances. + + If the trigger is set relative to START, then the "DTSTART" + property MUST be present in the associated "VEVENT" or "VTODO" + calendar component. If an alarm is specified for an event with + the trigger set relative to the END, then the "DTEND" property or + the "DTSTART" and "DURATION " properties MUST be present in the + associated "VEVENT" calendar component. If the alarm is specified + for a to-do with a trigger set relative to the END, then either + the "DUE" property or the "DTSTART" and "DURATION " properties + MUST be present in the associated "VTODO" calendar component. + + Alarms specified in an event or to-do that is defined in terms of + a DATE value type will be triggered relative to 00:00:00 of the + user's configured time zone on the specified date, or relative to + 00:00:00 UTC on the specified date if no configured time zone can + be found for the user. For example, if "DTSTART" is a DATE value + + + +Desruisseaux Standards Track [Page 134] + +RFC 5545 iCalendar September 2009 + + + set to 19980205 then the duration trigger will be relative to + 19980205T000000 America/New_York for a user configured with the + America/New_York time zone. + + Format Definition: This property is defined by the following + notation: + + trigger = "TRIGGER" (trigrel / trigabs) CRLF + + trigrel = *( + ; + ; The following are OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" "VALUE" "=" "DURATION") / + (";" trigrelparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) ":" dur-value + + trigabs = *( + ; + ; The following is REQUIRED, + ; but MUST NOT occur more than once. + ; + (";" "VALUE" "=" "DATE-TIME") / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) ":" date-time + + Example: A trigger set 15 minutes prior to the start of the event or + to-do. + + TRIGGER:-PT15M + + A trigger set five minutes after the end of an event or the due + date of a to-do. + + TRIGGER;RELATED=END:PT5M + + + + +Desruisseaux Standards Track [Page 135] + +RFC 5545 iCalendar September 2009 + + + A trigger set to an absolute DATE-TIME. + + TRIGGER;VALUE=DATE-TIME:19980101T050000Z + +3.8.7. Change Management Component Properties + + The following properties specify change management information in + calendar components. + +3.8.7.1. Date-Time Created + + Property Name: CREATED + + Purpose: This property specifies the date and time that the calendar + information was created by the calendar user agent in the calendar + store. + + Note: This is analogous to the creation date and time for a + file in the file system. + + Value Type: DATE-TIME + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: The property can be specified once in "VEVENT", + "VTODO", or "VJOURNAL" calendar components. The value MUST be + specified as a date with UTC time. + + Description: This property specifies the date and time that the + calendar information was created by the calendar user agent in the + calendar store. + + Format Definition: This property is defined by the following + notation: + + created = "CREATED" creaparam ":" date-time CRLF + + creaparam = *(";" other-param) + + Example: The following is an example of this property: + + CREATED:19960329T133000Z + + + + + + + + +Desruisseaux Standards Track [Page 136] + +RFC 5545 iCalendar September 2009 + + +3.8.7.2. Date-Time Stamp + + Property Name: DTSTAMP + + Purpose: In the case of an iCalendar object that specifies a + "METHOD" property, this property specifies the date and time that + the instance of the iCalendar object was created. In the case of + an iCalendar object that doesn't specify a "METHOD" property, this + property specifies the date and time that the information + associated with the calendar component was last revised in the + calendar store. + + Value Type: DATE-TIME + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property MUST be included in the "VEVENT", + "VTODO", "VJOURNAL", or "VFREEBUSY" calendar components. + + Description: The value MUST be specified in the UTC time format. + + This property is also useful to protocols such as [2447bis] that + have inherent latency issues with the delivery of content. This + property will assist in the proper sequencing of messages + containing iCalendar objects. + + In the case of an iCalendar object that specifies a "METHOD" + property, this property differs from the "CREATED" and "LAST- + MODIFIED" properties. These two properties are used to specify + when the particular calendar data in the calendar store was + created and last modified. This is different than when the + iCalendar object representation of the calendar service + information was created or last modified. + + In the case of an iCalendar object that doesn't specify a "METHOD" + property, this property is equivalent to the "LAST-MODIFIED" + property. + + Format Definition: This property is defined by the following + notation: + + dtstamp = "DTSTAMP" stmparam ":" date-time CRLF + + stmparam = *(";" other-param) + + + + + + +Desruisseaux Standards Track [Page 137] + +RFC 5545 iCalendar September 2009 + + + Example: + + DTSTAMP:19971210T080000Z + +3.8.7.3. Last Modified + + Property Name: LAST-MODIFIED + + Purpose: This property specifies the date and time that the + information associated with the calendar component was last + revised in the calendar store. + + Note: This is analogous to the modification date and time for a + file in the file system. + + Value Type: DATE-TIME + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + Conformance: This property can be specified in the "VEVENT", + "VTODO", "VJOURNAL", or "VTIMEZONE" calendar components. + + Description: The property value MUST be specified in the UTC time + format. + + Format Definition: This property is defined by the following + notation: + + last-mod = "LAST-MODIFIED" lstparam ":" date-time CRLF + + lstparam = *(";" other-param) + + Example: The following is an example of this property: + + LAST-MODIFIED:19960817T133000Z + +3.8.7.4. Sequence Number + + Property Name: SEQUENCE + + Purpose: This property defines the revision sequence number of the + calendar component within a sequence of revisions. + + Value Type: INTEGER + + Property Parameters: IANA and non-standard property parameters can + be specified on this property. + + + +Desruisseaux Standards Track [Page 138] + +RFC 5545 iCalendar September 2009 + + + Conformance: The property can be specified in "VEVENT", "VTODO", or + "VJOURNAL" calendar component. + + Description: When a calendar component is created, its sequence + number is 0. It is monotonically incremented by the "Organizer's" + CUA each time the "Organizer" makes a significant revision to the + calendar component. + + The "Organizer" includes this property in an iCalendar object that + it sends to an "Attendee" to specify the current version of the + calendar component. + + The "Attendee" includes this property in an iCalendar object that + it sends to the "Organizer" to specify the version of the calendar + component to which the "Attendee" is referring. + + A change to the sequence number is not the mechanism that an + "Organizer" uses to request a response from the "Attendees". The + "RSVP" parameter on the "ATTENDEE" property is used by the + "Organizer" to indicate that a response from the "Attendees" is + requested. + + Recurrence instances of a recurring component MAY have different + sequence numbers. + + Format Definition: This property is defined by the following + notation: + + seq = "SEQUENCE" seqparam ":" integer CRLF + ; Default is "0" + + seqparam = *(";" other-param) + + Example: The following is an example of this property for a calendar + component that was just created by the "Organizer": + + SEQUENCE:0 + + The following is an example of this property for a calendar + component that has been revised two different times by the + "Organizer": + + SEQUENCE:2 + +3.8.8. Miscellaneous Component Properties + + The following properties specify information about a number of + miscellaneous features of calendar components. + + + +Desruisseaux Standards Track [Page 139] + +RFC 5545 iCalendar September 2009 + + +3.8.8.1. IANA Properties + + Property Name: An IANA-registered property name + + Value Type: The default value type is TEXT. The value type can be + set to any value type. + + Property Parameters: Any parameter can be specified on this + property. + + Description: This specification allows other properties registered + with IANA to be specified in any calendar components. Compliant + applications are expected to be able to parse these other IANA- + registered properties but can ignore them. + + Format Definition: This property is defined by the following + notation: + + iana-prop = iana-token *(";" icalparameter) ":" value CRLF + + Example: The following are examples of properties that might be + registered to IANA: + + DRESSCODE:CASUAL + + NON-SMOKING;VALUE=BOOLEAN:TRUE + +3.8.8.2. Non-Standard Properties + + Property Name: Any property name with a "X-" prefix + + Purpose: This class of property provides a framework for defining + non-standard properties. + + Value Type: The default value type is TEXT. The value type can be + set to any value type. + + Property Parameters: IANA, non-standard, and language property + parameters can be specified on this property. + + Conformance: This property can be specified in any calendar + component. + + Description: The MIME Calendaring and Scheduling Content Type + provides a "standard mechanism for doing non-standard things". + This extension support is provided for implementers to "push the + envelope" on the existing version of the memo. Extension + properties are specified by property and/or property parameter + + + +Desruisseaux Standards Track [Page 140] + +RFC 5545 iCalendar September 2009 + + + names that have the prefix text of "X-" (the two-character + sequence: LATIN CAPITAL LETTER X character followed by the HYPHEN- + MINUS character). It is recommended that vendors concatenate onto + this sentinel another short prefix text to identify the vendor. + This will facilitate readability of the extensions and minimize + possible collision of names between different vendors. User + agents that support this content type are expected to be able to + parse the extension properties and property parameters but can + ignore them. + + At present, there is no registration authority for names of + extension properties and property parameters. The value type for + this property is TEXT. Optionally, the value type can be any of + the other valid value types. + + Format Definition: This property is defined by the following + notation: + + x-prop = x-name *(";" icalparameter) ":" value CRLF + + Example: The following might be the ABC vendor's extension for an + audio-clip form of subject property: + + X-ABC-MMSUBJ;VALUE=URI;FMTTYPE=audio/basic:http://www.example. + org/mysubj.au + +3.8.8.3. Request Status + + Property Name: REQUEST-STATUS + + Purpose: This property defines the status code returned for a + scheduling request. + + Value Type: TEXT + + Property Parameters: IANA, non-standard, and language property + parameters can be specified on this property. + + Conformance: The property can be specified in the "VEVENT", "VTODO", + "VJOURNAL", or "VFREEBUSY" calendar component. + + Description: This property is used to return status code information + related to the processing of an associated iCalendar object. The + value type for this property is TEXT. + + + + + + + +Desruisseaux Standards Track [Page 141] + +RFC 5545 iCalendar September 2009 + + + The value consists of a short return status component, a longer + return status description component, and optionally a status- + specific data component. The components of the value are + separated by the SEMICOLON character. + + The short return status is a PERIOD character separated pair or + 3-tuple of integers. For example, "3.1" or "3.1.1". The + successive levels of integers provide for a successive level of + status code granularity. + + The following are initial classes for the return status code. + Individual iCalendar object methods will define specific return + status codes for these classes. In addition, other classes for + the return status code may be defined using the registration + process defined later in this memo. + + +--------+----------------------------------------------------------+ + | Short | Longer Return Status Description | + | Return | | + | Status | | + | Code | | + +--------+----------------------------------------------------------+ + | 1.xx | Preliminary success. This class of status code | + | | indicates that the request has been initially processed | + | | but that completion is pending. | + | | | + | 2.xx | Successful. This class of status code indicates that | + | | the request was completed successfully. However, the | + | | exact status code can indicate that a fallback has been | + | | taken. | + | | | + | 3.xx | Client Error. This class of status code indicates that | + | | the request was not successful. The error is the result | + | | of either a syntax or a semantic error in the client- | + | | formatted request. Request should not be retried until | + | | the condition in the request is corrected. | + | | | + | 4.xx | Scheduling Error. This class of status code indicates | + | | that the request was not successful. Some sort of error | + | | occurred within the calendaring and scheduling service, | + | | not directly related to the request itself. | + +--------+----------------------------------------------------------+ + + + + + + + + + +Desruisseaux Standards Track [Page 142] + +RFC 5545 iCalendar September 2009 + + + Format Definition: This property is defined by the following + notation: + + rstatus = "REQUEST-STATUS" rstatparam ":" + statcode ";" statdesc [";" extdata] + + rstatparam = *( + ; + ; The following is OPTIONAL, + ; but MUST NOT occur more than once. + ; + (";" languageparam) / + ; + ; The following is OPTIONAL, + ; and MAY occur more than once. + ; + (";" other-param) + ; + ) + + statcode = 1*DIGIT 1*2("." 1*DIGIT) + ;Hierarchical, numeric return status code + + statdesc = text + ;Textual status description + + extdata = text + ;Textual exception data. For example, the offending property + ;name and value or complete property line. + + Example: The following are some possible examples of this property. + + The COMMA and SEMICOLON separator characters in the property value + are BACKSLASH character escaped because they appear in a text + value. + + REQUEST-STATUS:2.0;Success + + REQUEST-STATUS:3.1;Invalid property value;DTSTART:96-Apr-01 + + REQUEST-STATUS:2.8; Success\, repeating event ignored. Scheduled + as a single event.;RRULE:FREQ=WEEKLY\;INTERVAL=2 + + REQUEST-STATUS:4.1;Event conflict. Date-time is busy. + + REQUEST-STATUS:3.7;Invalid calendar user;ATTENDEE: + mailto:jsmith@example.com + + + + +Desruisseaux Standards Track [Page 143] + +RFC 5545 iCalendar September 2009 + + +4. iCalendar Object Examples + + The following examples are provided as an informational source of + illustrative iCalendar objects consistent with this content type. + + The following example specifies a three-day conference that begins at + 2:30 P.M. UTC, September 18, 1996 and ends at 10:00 P.M. UTC, + September 20, 1996. + + BEGIN:VCALENDAR + PRODID:-//xyz Corp//NONSGML PDA Calendar Version 1.0//EN + VERSION:2.0 + BEGIN:VEVENT + DTSTAMP:19960704T120000Z + UID:uid1@example.com + ORGANIZER:mailto:jsmith@example.com + DTSTART:19960918T143000Z + DTEND:19960920T220000Z + STATUS:CONFIRMED + CATEGORIES:CONFERENCE + SUMMARY:Networld+Interop Conference + DESCRIPTION:Networld+Interop Conference + and Exhibit\nAtlanta World Congress Center\n + Atlanta\, Georgia + END:VEVENT + END:VCALENDAR + + The following example specifies a group-scheduled meeting that begins + at 8:30 AM EST on March 12, 1998 and ends at 9:30 AM EST on March 12, + 1998. The "Organizer" has scheduled the meeting with one or more + calendar users in a group. A time zone specification for Eastern + United States has been specified. + + BEGIN:VCALENDAR + PRODID:-//RDU Software//NONSGML HandCal//EN + VERSION:2.0 + BEGIN:VTIMEZONE + TZID:America/New_York + BEGIN:STANDARD + DTSTART:19981025T020000 + TZOFFSETFROM:-0400 + TZOFFSETTO:-0500 + TZNAME:EST + END:STANDARD + BEGIN:DAYLIGHT + DTSTART:19990404T020000 + TZOFFSETFROM:-0500 + TZOFFSETTO:-0400 + + + +Desruisseaux Standards Track [Page 144] + +RFC 5545 iCalendar September 2009 + + + TZNAME:EDT + END:DAYLIGHT + END:VTIMEZONE + BEGIN:VEVENT + DTSTAMP:19980309T231000Z + UID:guid-1.example.com + ORGANIZER:mailto:mrbig@example.com + ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT;CUTYPE=GROUP: + mailto:employee-A@example.com + DESCRIPTION:Project XYZ Review Meeting + CATEGORIES:MEETING + CLASS:PUBLIC + CREATED:19980309T130000Z + SUMMARY:XYZ Project Review + DTSTART;TZID=America/New_York:19980312T083000 + DTEND;TZID=America/New_York:19980312T093000 + LOCATION:1CP Conference Room 4350 + END:VEVENT + END:VCALENDAR + + The following is an example of an iCalendar object passed in a MIME + message with a single body part consisting of a "text/calendar" + Content Type. + + TO:jsmith@example.com + FROM:jdoe@example.com + MIME-VERSION:1.0 + MESSAGE-ID: + CONTENT-TYPE:text/calendar; method="xyz"; component="VEVENT" + + BEGIN:VCALENDAR + METHOD:xyz + VERSION:2.0 + PRODID:-//ABC Corporation//NONSGML My Product//EN + BEGIN:VEVENT + DTSTAMP:19970324T120000Z + SEQUENCE:0 + UID:uid3@example.com + ORGANIZER:mailto:jdoe@example.com + ATTENDEE;RSVP=TRUE:mailto:jsmith@example.com + DTSTART:19970324T123000Z + DTEND:19970324T210000Z + CATEGORIES:MEETING,PROJECT + CLASS:PUBLIC + SUMMARY:Calendaring Interoperability Planning Meeting + DESCRIPTION:Discuss how we can test c&s interoperability\n + using iCalendar and other IETF standards. + LOCATION:LDB Lobby + + + +Desruisseaux Standards Track [Page 145] + +RFC 5545 iCalendar September 2009 + + + ATTACH;FMTTYPE=application/postscript:ftp://example.com/pub/ + conf/bkgrnd.ps + END:VEVENT + END:VCALENDAR + + The following is an example of a to-do due on April 15, 1998. An + audio alarm has been specified to remind the calendar user at noon, + the day before the to-do is expected to be completed and repeat + hourly, four additional times. The to-do definition has been + modified twice since it was initially created. + + BEGIN:VCALENDAR + VERSION:2.0 + PRODID:-//ABC Corporation//NONSGML My Product//EN + BEGIN:VTODO + DTSTAMP:19980130T134500Z + SEQUENCE:2 + UID:uid4@example.com + ORGANIZER:mailto:unclesam@example.com + ATTENDEE;PARTSTAT=ACCEPTED:mailto:jqpublic@example.com + DUE:19980415T000000 + STATUS:NEEDS-ACTION + SUMMARY:Submit Income Taxes + BEGIN:VALARM + ACTION:AUDIO + TRIGGER:19980403T120000Z + ATTACH;FMTTYPE=audio/basic:http://example.com/pub/audio- + files/ssbanner.aud + REPEAT:4 + DURATION:PT1H + END:VALARM + END:VTODO + END:VCALENDAR + + The following is an example of a journal entry: + + BEGIN:VCALENDAR + VERSION:2.0 + PRODID:-//ABC Corporation//NONSGML My Product//EN + BEGIN:VJOURNAL + DTSTAMP:19970324T120000Z + UID:uid5@example.com + ORGANIZER:mailto:jsmith@example.com + STATUS:DRAFT + CLASS:PUBLIC + CATEGORIES:Project Report,XYZ,Weekly Meeting + DESCRIPTION:Project xyz Review Meeting Minutes\n + Agenda\n1. Review of project version 1.0 requirements.\n2. + + + +Desruisseaux Standards Track [Page 146] + +RFC 5545 iCalendar September 2009 + + + Definition + of project processes.\n3. Review of project schedule.\n + Participants: John Smith\, Jane Doe\, Jim Dandy\n-It was + decided that the requirements need to be signed off by + product marketing.\n-Project processes were accepted.\n + -Project schedule needs to account for scheduled holidays + and employee vacation time. Check with HR for specific + dates.\n-New schedule will be distributed by Friday.\n- + Next weeks meeting is cancelled. No meeting until 3/23. + END:VJOURNAL + END:VCALENDAR + + The following is an example of published busy time information. The + iCalendar object might be placed in the network resource + http://www.example.com/calendar/busytime/jsmith.ifb. + + BEGIN:VCALENDAR + VERSION:2.0 + PRODID:-//RDU Software//NONSGML HandCal//EN + BEGIN:VFREEBUSY + ORGANIZER:mailto:jsmith@example.com + DTSTART:19980313T141711Z + DTEND:19980410T141711Z + FREEBUSY:19980314T233000Z/19980315T003000Z + FREEBUSY:19980316T153000Z/19980316T163000Z + FREEBUSY:19980318T030000Z/19980318T040000Z + URL:http://www.example.com/calendar/busytime/jsmith.ifb + END:VFREEBUSY + END:VCALENDAR + +5. Recommended Practices + + These recommended practices should be followed in order to assure + consistent handling of the following cases for an iCalendar object. + + 1. Content lines longer than 75 octets SHOULD be folded. + + 2. When the combination of the "RRULE" and "RDATE" properties in a + recurring component produces multiple instances having the same + start DATE-TIME value, they should be collapsed to, and + considered as, a single instance. If the "RDATE" property is + specified as a PERIOD value the duration of the recurrence + instance will be the one specified by the "RDATE" property, and + not the duration of the recurrence instance defined by the + "DTSTART" property. + + 3. When a calendar user receives multiple requests for the same + calendar component (e.g., REQUEST for a "VEVENT" calendar + + + +Desruisseaux Standards Track [Page 147] + +RFC 5545 iCalendar September 2009 + + + component) as a result of being on multiple mailing lists + specified by "ATTENDEE" properties in the request, they SHOULD + respond to only one of the requests. The calendar user SHOULD + also specify (using the "MEMBER" parameter of the "ATTENDEE" + property) of which mailing list they are a member. + + 4. An implementation can truncate a "SUMMARY" property value to 255 + octets, but it MUST NOT truncate the value in the middle of a + UTF-8 multi-octet sequence. + + 5. If seconds of the minute are not supported by an implementation, + then a value of "00" SHOULD be specified for the seconds + component in a time value. + + 6. "TZURL" values SHOULD NOT be specified as a file URI type. This + URI form can be useful within an organization, but is problematic + in the Internet. + + 7. Some possible English values for "CATEGORIES" property include: + "ANNIVERSARY", "APPOINTMENT", "BUSINESS", "EDUCATION", "HOLIDAY", + "MEETING", "MISCELLANEOUS", "NON-WORKING HOURS", "NOT IN OFFICE", + "PERSONAL", "PHONE CALL", "SICK DAY", "SPECIAL OCCASION", + "TRAVEL", "VACATION". Categories can be specified in any + registered language. + + 8. Some possible English values for the "RESOURCES" property + include: "CATERING", "CHAIRS", "COMPUTER PROJECTOR", "EASEL", + "OVERHEAD PROJECTOR", "SPEAKER PHONE", "TABLE", "TV", "VCR", + "VIDEO PHONE", "VEHICLE". Resources can be specified in any + registered language. + +6. Internationalization Considerations + + Applications MUST generate iCalendar streams in the UTF-8 charset and + MUST accept an iCalendar stream in the UTF-8 or US-ASCII charset. + +7. Security Considerations + + Because calendaring and scheduling information is very privacy- + sensitive, the protocol used for the transmission of calendaring and + scheduling information should have capabilities to protect the + information from possible threats, such as eavesdropping, replay, + message insertion, deletion, modification, and man-in-the-middle + attacks. + + As this document only defines the data format and media type of text/ + calendar that is independent of any calendar service or protocol, it + is up to the actual protocol specifications such as iTIP [2446bis], + + + +Desruisseaux Standards Track [Page 148] + +RFC 5545 iCalendar September 2009 + + + iMIP [2447bis], and "Calendaring Extensions to WebDAV (CalDAV)" + [RFC4791] to describe the threats that the above attacks present, as + well as ways in which to mitigate them. + +8. IANA Considerations + +8.1. iCalendar Media Type Registration + + The Calendaring and Scheduling Core Object Specification is intended + for use as a MIME content type. + + To: ietf-types@iana.org + + Subject: Registration of media type text/calendar + + Type name: text + + Subtype name: calendar + + Required parameters: none + + Optional parameters: charset, method, component, and optinfo + + The "charset" parameter is defined in [RFC2046] for subtypes of + the "text" media type. It is used to indicate the charset used in + the body part. The charset supported by this revision of + iCalendar is UTF-8. The use of any other charset is deprecated by + this revision of iCalendar; however, note that this revision + requires that compliant applications MUST accept iCalendar streams + using either the UTF-8 or US-ASCII charset. + + The "method" parameter is used to convey the iCalendar object + method or transaction semantics for the calendaring and scheduling + information. It also is an identifier for the restricted set of + properties and values of which the iCalendar object consists. The + parameter is to be used as a guide for applications interpreting + the information contained within the body part. It SHOULD NOT be + used to exclude or require particular pieces of information unless + the identified method definition specifically calls for this + behavior. Unless specifically forbidden by a particular method + definition, a text/calendar content type can contain any set of + properties permitted by the Calendaring and Scheduling Core Object + Specification. The "method" parameter MUST be specified and MUST + be set to the same value as the "METHOD" component property of the + iCalendar objects of the iCalendar stream if and only if the + iCalendar objects in the iCalendar stream all have a "METHOD" + component property set to the same value. + + + + +Desruisseaux Standards Track [Page 149] + +RFC 5545 iCalendar September 2009 + + + The value for the "method" parameter is defined as follows: + + method = 1*(ALPHA / DIGIT / "-") + ; IANA-registered iCalendar object method + + The "component" parameter conveys the type of iCalendar calendar + component within the body part. If the iCalendar object contains + more than one calendar component type, then multiple component + parameters MUST be specified. + + The value for the "component" parameter is defined as follows: + + component = "VEVENT" + / "VTODO" + / "VJOURNAL" + / "VFREEBUSY" + / "VTIMEZONE" + / iana-token + / x-name + + The "optinfo" parameter conveys optional information about the + iCalendar object within the body part. This parameter can only + specify semantics already specified by the iCalendar object and + that can be otherwise determined by parsing the body part. In + addition, the optional information specified by this parameter + MUST be consistent with that information specified by the + iCalendar object. For example, it can be used to convey the + "Attendee" response status to a meeting request. The parameter + value consists of a string value. + + The parameter can be specified multiple times. + + The value for the "optinfo" parameter is defined as follows: + + optinfo = infovalue / qinfovalue + + infovalue = iana-token / x-name + + qinfovalue = DQUOTE (infovalue) DQUOTE + + Encoding considerations: This media type can contain 8bit + characters, so the use of quoted-printable or base64 MIME Content- + Transfer-Encodings might be necessary when iCalendar objects are + transferred across protocols restricted to the 7bit repertoire. + Note that a text valued property in the content entity can also + have content encoding of special characters using a BACKSLASH + character escapement technique. This means that content values + can end up being encoded twice. + + + +Desruisseaux Standards Track [Page 150] + +RFC 5545 iCalendar September 2009 + + + Security considerations: See Section 7. + + Interoperability considerations: This media type is intended to + define a common format for conveying calendaring and scheduling + information between different systems. It is heavily based on the + earlier [VCAL] industry specification. + + Published specification: This specification. + + Applications that use this media type: This media type is designed + for widespread use by Internet calendaring and scheduling + applications. In addition, applications in the workflow and + document management area might find this content-type applicable. + The iTIP [2446bis], iMIP [2447bis], and CalDAV [RFC4791] Internet + protocols directly use this media type also. + + Additional information: + + Magic number(s): None. + + File extension(s): The file extension of "ics" is to be used to + designate a file containing (an arbitrary set of) calendaring + and scheduling information consistent with this MIME content + type. + + The file extension of "ifb" is to be used to designate a file + containing free or busy time information consistent with this + MIME content type. + + Macintosh file type code(s): The file type code of "iCal" is to + be used in Apple MacIntosh operating system environments to + designate a file containing calendaring and scheduling + information consistent with this MIME media type. + + The file type code of "iFBf" is to be used in Apple MacIntosh + operating system environments to designate a file containing + free or busy time information consistent with this MIME media + type. + + Person & email address to contact for further information: See the + "Author's Address" section of this document. + + Intended usage: COMMON + + Restrictions on usage: There are no restrictions on where this media + type can be used. + + Author: See the "Author's Address" section of this document. + + + +Desruisseaux Standards Track [Page 151] + +RFC 5545 iCalendar September 2009 + + + Change controller: IETF + +8.2. New iCalendar Elements Registration + + This section defines the process to register new or modified + iCalendar elements, that is, components, properties, parameters, + value data types, and values, with IANA. + +8.2.1. iCalendar Elements Registration Procedure + + The IETF will create a mailing list, icalendar@ietf.org, which can be + used for public discussion of iCalendar elements proposals prior to + registration. Use of the mailing list is strongly encouraged. The + IESG will appoint a designated expert who will monitor the + icalendar@ietf.org mailing list and review registrations. + + Registration of new iCalendar elements MUST be reviewed by the + designated expert and published in an RFC. A Standards Track RFC is + REQUIRED for the registration of new value data types that modify + existing properties, as well as for the registration of participation + status values to be used in "VEVENT" calendar components. A + Standards Track RFC is also REQUIRED for registration of iCalendar + elements that modify iCalendar elements previously documented in a + Standards Track RFC. + + The registration procedure begins when a completed registration + template, defined in the sections below, is sent to + icalendar@ietf.org and iana@iana.org. The designated expert is + expected to tell IANA and the submitter of the registration within + two weeks whether the registration is approved, approved with minor + changes, or rejected with cause. When a registration is rejected + with cause, it can be re-submitted if the concerns listed in the + cause are addressed. Decisions made by the designated expert can be + appealed to the IESG Applications Area Director, then to the IESG. + They follow the normal appeals procedure for IESG decisions. + +8.2.2. Registration Template for Components + + A component is defined by completing the following template. + + Component name: The name of the component. + + Purpose: The purpose of the component. Give a short but clear + description. + + Format definition: The ABNF for the component definition needs to be + specified. + + + + +Desruisseaux Standards Track [Page 152] + +RFC 5545 iCalendar September 2009 + + + Description: Any special notes about the component, how it is to be + used, etc. + + Example(s): One or more examples of instances of the component need + to be specified. + +8.2.3. Registration Template for Properties + + A property is defined by completing the following template. + + Property name: The name of the property. + + Purpose: The purpose of the property. Give a short but clear + description. + + Value type: Any of the valid value types for the property value need + to be specified. The default value type also needs to be + specified. + + Property parameters: Any of the valid property parameters for the + property MUST be specified. + + Conformance: The calendar components in which the property can + appear MUST be specified. + + Description: Any special notes about the property, how it is to be + used, etc. + + Format definition: The ABNF for the property definition needs to be + specified. + + Example(s): One or more examples of instances of the property need + to be specified. + +8.2.4. Registration Template for Parameters + + A parameter is defined by completing the following template. + + Parameter name: The name of the parameter. + + Purpose: The purpose of the parameter. Give a short but clear + description. + + Format definition: The ABNF for the parameter definition needs to be + specified. + + Description: Any special notes about the parameter, how it is to be + used, etc. + + + +Desruisseaux Standards Track [Page 153] + +RFC 5545 iCalendar September 2009 + + + Example(s): One or more examples of instances of the parameter need + to be specified. + +8.2.5. Registration Template for Value Data Types + + A value data type is defined by completing the following template. + + Value name: The name of the value type. + + Purpose: The purpose of the value type. Give a short but clear + description. + + Format definition: The ABNF for the value type definition needs to + be specified. + + Description: Any special notes about the value type, how it is to be + used, etc. + + Example(s): One or more examples of instances of the value type need + to be specified. + +8.2.6. Registration Template for Values + + A value is defined by completing the following template. + + Value: The value literal. + + Purpose: The purpose of the value. Give a short but clear + description. + + Conformance: The calendar properties and/or parameters that can take + this value need to be specified. + + Example(s): One or more examples of instances of the value need to + be specified. + + The following is a fictitious example of a registration of an + iCalendar value: + + Value: TOP-SECRET + + Purpose: This value is used to specify the access classification of + top-secret calendar components. + + Conformance: This value can be used with the "CLASS" property. + + + + + + +Desruisseaux Standards Track [Page 154] + +RFC 5545 iCalendar September 2009 + + + Example(s): The following is an example of this value used with the + "CLASS" property: + + CLASS:TOP-SECRET + +8.3. Initial iCalendar Elements Registries + + The IANA created and maintains the following registries for iCalendar + elements with pointers to appropriate reference documents. + +8.3.1. Components Registry + + The following table has been used to initialize the components + registry. + + +-----------+---------+-------------------------+ + | Component | Status | Reference | + +-----------+---------+-------------------------+ + | VCALENDAR | Current | RFC 5545, Section 3.4 | + | | | | + | VEVENT | Current | RFC 5545, Section 3.6.1 | + | | | | + | VTODO | Current | RFC 5545, Section 3.6.2 | + | | | | + | VJOURNAL | Current | RFC 5545, Section 3.6.3 | + | | | | + | VFREEBUSY | Current | RFC 5545, Section 3.6.4 | + | | | | + | VTIMEZONE | Current | RFC 5545, Section 3.6.5 | + | | | | + | VALARM | Current | RFC 5545, Section 3.6.6 | + | | | | + | STANDARD | Current | RFC 5545, Section 3.6.5 | + | | | | + | DAYLIGHT | Current | RFC 5545, Section 3.6.5 | + +-----------+---------+-------------------------+ + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 155] + +RFC 5545 iCalendar September 2009 + + +8.3.2. Properties Registry + + The following table is has been used to initialize the properties + registry. + + +------------------+------------+----------------------------+ + | Property | Status | Reference | + +------------------+------------+----------------------------+ + | CALSCALE | Current | RFC 5545, Section 3.7.1 | + | METHOD | Current | RFC 5545, Section 3.7.2 | + | | | | + | PRODID | Current | RFC 5545, Section 3.7.3 | + | | | | + | VERSION | Current | RFC 5545, Section 3.7.4 | + | | | | + | ATTACH | Current | RFC 5545, Section 3.8.1.1 | + | | | | + | CATEGORIES | Current | RFC 5545, Section 3.8.1.2 | + | | | | + | CLASS | Current | RFC 5545, Section 3.8.1.3 | + | | | | + | COMMENT | Current | RFC 5545, Section 3.8.1.4 | + | | | | + | DESCRIPTION | Current | RFC 5545, Section 3.8.1.5 | + | | | | + | GEO | Current | RFC 5545, Section 3.8.1.6 | + | | | | + | LOCATION | Current | RFC 5545, Section 3.8.1.7 | + | | | | + | PERCENT-COMPLETE | Current | RFC 5545, Section 3.8.1.8 | + | | | | + | PRIORITY | Current | RFC 5545, Section 3.8.1.9 | + | | | | + | RESOURCES | Current | RFC 5545, Section 3.8.1.10 | + | | | | + | STATUS | Current | RFC 5545, Section 3.8.1.11 | + | | | | + | SUMMARY | Current | RFC 5545, Section 3.8.1.12 | + | | | | + | COMPLETED | Current | RFC 5545, Section 3.8.2.1 | + | | | | + | DTEND | Current | RFC 5545, Section 3.8.2.2 | + | | | | + | DUE | Current | RFC 5545, Section 3.8.2.3 | + | | | | + | DTSTART | Current | RFC 5545, Section 3.8.2.4 | + | | | | + | DURATION | Current | RFC 5545, Section 3.8.2.5 | + + + +Desruisseaux Standards Track [Page 156] + +RFC 5545 iCalendar September 2009 + + + | | | | + | FREEBUSY | Current | RFC 5545, Section 3.8.2.6 | + | | | | + | TRANSP | Current | RFC 5545, Section 3.8.2.7 | + | | | | + | TZID | Current | RFC 5545, Section 3.8.3.1 | + | | | | + | TZNAME | Current | RFC 5545, Section 3.8.3.2 | + | | | | + | TZOFFSETFROM | Current | RFC 5545, Section 3.8.3.3 | + | | | | + | TZOFFSETTO | Current | RFC 5545, Section 3.8.3.4 | + | | | | + | TZURL | Current | RFC 5545, Section 3.8.3.5 | + | | | | + | ATTENDEE | Current | RFC 5545, Section 3.8.4.1 | + | | | | + | CONTACT | Current | RFC 5545, Section 3.8.4.2 | + | | | | + | ORGANIZER | Current | RFC 5545, Section 3.8.4.3 | + | | | | + | RECURRENCE-ID | Current | RFC 5545, Section 3.8.4.4 | + | | | | + | RELATED-TO | Current | RFC 5545, Section 3.8.4.5 | + | | | | + | URL | Current | RFC 5545, Section 3.8.4.6 | + | | | | + | UID | Current | RFC 5545, Section 3.8.4.7 | + | | | | + | EXDATE | Current | RFC 5545, Section 3.8.5.1 | + | | | | + | EXRULE | Deprecated | [RFC2445], Section 4.8.5.2 | + | | | | + | RDATE | Current | RFC 5545, Section 3.8.5.2 | + | | | | + | RRULE | Current | RFC 5545, Section 3.8.5.3 | + | | | | + | ACTION | Current | RFC 5545, Section 3.8.6.1 | + | | | | + | REPEAT | Current | RFC 5545, Section 3.8.6.2 | + | | | | + | TRIGGER | Current | RFC 5545, Section 3.8.6.3 | + | | | | + | CREATED | Current | RFC 5545, Section 3.8.7.1 | + | | | | + | DTSTAMP | Current | RFC 5545, Section 3.8.7.2 | + | | | | + | LAST-MODIFIED | Current | RFC 5545, Section 3.8.7.3 | + + + +Desruisseaux Standards Track [Page 157] + +RFC 5545 iCalendar September 2009 + + + | | | | + | SEQUENCE | Current | RFC 5545, Section 3.8.7.4 | + | | | | + | REQUEST-STATUS | Current | RFC 5545, Section 3.8.8.3 | + +------------------+------------+----------------------------+ + +8.3.3. Parameters Registry + + The following table has been used to initialize the parameters + registry. + + +----------------+---------+--------------------------+ + | Parameter | Status | Reference | + +----------------+---------+--------------------------+ + | ALTREP | Current | RFC 5545, Section 3.2.1 | + | | | | + | CN | Current | RFC 5545, Section 3.2.2 | + | | | | + | CUTYPE | Current | RFC 5545, Section 3.2.3 | + | | | | + | DELEGATED-FROM | Current | RFC 5545, Section 3.2.4 | + | | | | + | DELEGATED-TO | Current | RFC 5545, Section 3.2.5 | + | | | | + | DIR | Current | RFC 5545, Section 3.2.6 | + | | | | + | ENCODING | Current | RFC 5545, Section 3.2.7 | + | | | | + | FMTTYPE | Current | RFC 5545, Section 3.2.8 | + | | | | + | FBTYPE | Current | RFC 5545, Section 3.2.9 | + | | | | + | LANGUAGE | Current | RFC 5545, Section 3.2.10 | + | | | | + | MEMBER | Current | RFC 5545, Section 3.2.11 | + | | | | + | PARTSTAT | Current | RFC 5545, Section 3.2.12 | + | | | | + | RANGE | Current | RFC 5545, Section 3.2.13 | + | | | | + | RELATED | Current | RFC 5545, Section 3.2.14 | + | | | | + | RELTYPE | Current | RFC 5545, Section 3.2.15 | + | | | | + | ROLE | Current | RFC 5545, Section 3.2.16 | + | | | | + | RSVP | Current | RFC 5545, Section 3.2.17 | + | | | | + + + +Desruisseaux Standards Track [Page 158] + +RFC 5545 iCalendar September 2009 + + + | SENT-BY | Current | RFC 5545, Section 3.2.18 | + | | | | + | TZID | Current | RFC 5545, Section 3.2.19 | + | | | | + | VALUE | Current | RFC 5545, Section 3.2.20 | + +----------------+---------+--------------------------+ + +8.3.4. Value Data Types Registry + + The following table has been used to initialize the value data types + registry. + + +-----------------+---------+--------------------------+ + | Value Data Type | Status | Reference | + +-----------------+---------+--------------------------+ + | BINARY | Current | RFC 5545, Section 3.3.1 | + | | | | + | BOOLEAN | Current | RFC 5545, Section 3.3.2 | + | | | | + | CAL-ADDRESS | Current | RFC 5545, Section 3.3.3 | + | | | | + | DATE | Current | RFC 5545, Section 3.3.4 | + | | | | + | DATE-TIME | Current | RFC 5545, Section 3.3.5 | + | | | | + | DURATION | Current | RFC 5545, Section 3.3.6 | + | | | | + | FLOAT | Current | RFC 5545, Section 3.3.7 | + | | | | + | INTEGER | Current | RFC 5545, Section 3.3.8 | + | | | | + | PERIOD | Current | RFC 5545, Section 3.3.9 | + | | | | + | RECUR | Current | RFC 5545, Section 3.3.10 | + | | | | + | TEXT | Current | RFC 5545, Section 3.3.11 | + | | | | + | TIME | Current | RFC 5545, Section 3.3.12 | + | | | | + | URI | Current | RFC 5545, Section 3.3.13 | + | | | | + | UTC-OFFSET | Current | RFC 5545, Section 3.3.14 | + +-----------------+---------+--------------------------+ + + + + + + + + +Desruisseaux Standards Track [Page 159] + +RFC 5545 iCalendar September 2009 + + +8.3.5. Calendar User Types Registry + + The following table has been used to initialize the calendar user + types registry. + + +--------------------+---------+-------------------------+ + | Calendar User Type | Status | Reference | + +--------------------+---------+-------------------------+ + | INDIVIDUAL | Current | RFC 5545, Section 3.2.3 | + | | | | + | GROUP | Current | RFC 5545, Section 3.2.3 | + | | | | + | RESOURCE | Current | RFC 5545, Section 3.2.3 | + | | | | + | ROOM | Current | RFC 5545, Section 3.2.3 | + | | | | + | UNKNOWN | Current | RFC 5545, Section 3.2.3 | + +--------------------+---------+-------------------------+ + +8.3.6. Free/Busy Time Types Registry + + The following table has been used to initialize the free/busy time + types registry. + + +---------------------+---------+-------------------------+ + | Free/Busy Time Type | Status | Reference | + +---------------------+---------+-------------------------+ + | FREE | Current | RFC 5545, Section 3.2.9 | + | | | | + | BUSY | Current | RFC 5545, Section 3.2.9 | + | | | | + | BUSY-UNAVAILABLE | Current | RFC 5545, Section 3.2.9 | + | | | | + | BUSY-TENTATIVE | Current | RFC 5545, Section 3.2.9 | + +---------------------+---------+-------------------------+ + + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 160] + +RFC 5545 iCalendar September 2009 + + +8.3.7. Participation Statuses Registry + + The following table has been used to initialize the participation + statuses registry. + + +--------------------+---------+--------------------------+ + | Participant Status | Status | Reference | + +--------------------+---------+--------------------------+ + | NEEDS-ACTION | Current | RFC 5545, Section 3.2.12 | + | | | | + | ACCEPTED | Current | RFC 5545, Section 3.2.12 | + | | | | + | DECLINED | Current | RFC 5545, Section 3.2.12 | + | | | | + | TENTATIVE | Current | RFC 5545, Section 3.2.12 | + | | | | + | DELEGATED | Current | RFC 5545, Section 3.2.12 | + | | | | + | COMPLETED | Current | RFC 5545, Section 3.2.12 | + | | | | + | IN-PROCESS | Current | RFC 5545, Section 3.2.12 | + +--------------------+---------+--------------------------+ + +8.3.8. Relationship Types Registry + + The following table has been used to initialize the relationship + types registry. + + +-------------------+---------+--------------------------+ + | Relationship Type | Status | Reference | + +-------------------+---------+--------------------------+ + | CHILD | Current | RFC 5545, Section 3.2.15 | + | | | | + | PARENT | Current | RFC 5545, Section 3.2.15 | + | | | | + | SIBLING | Current | RFC 5545, Section 3.2.15 | + +-------------------+---------+--------------------------+ + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 161] + +RFC 5545 iCalendar September 2009 + + +8.3.9. Participation Roles Registry + + The following table has been used to initialize the participation + roles registry. + + +-----------------+---------+--------------------------+ + | Role Type | Status | Reference | + +-----------------+---------+--------------------------+ + | CHAIR | Current | RFC 5545, Section 3.2.16 | + | | | | + | REQ-PARTICIPANT | Current | RFC 5545, Section 3.2.16 | + | | | | + | OPT-PARTICIPANT | Current | RFC 5545, Section 3.2.16 | + | | | | + | NON-PARTICIPANT | Current | RFC 5545, Section 3.2.16 | + +-----------------+---------+--------------------------+ + +8.3.10. Actions Registry + + The following table has been used to initialize the actions registry. + + +-----------+------------+----------------------------+ + | Action | Status | Reference | + +-----------+------------+----------------------------+ + | AUDIO | Current | RFC 5545, Section 3.8.6.1 | + | | | | + | DISPLAY | Current | RFC 5545, Section 3.8.6.1 | + | | | | + | EMAIL | Current | RFC 5545, Section 3.8.6.1 | + | | | | + | PROCEDURE | Deprecated | [RFC2445], Section 4.8.6.1 | + +-----------+------------+----------------------------+ + +8.3.11. Classifications Registry + + The following table has been used to initialize the classifications + registry. + + +----------------+---------+---------------------------+ + | Classification | Status | Reference | + +----------------+---------+---------------------------+ + | PUBLIC | Current | RFC 5545, Section 3.8.1.3 | + | | | | + | PRIVATE | Current | RFC 5545, Section 3.8.1.3 | + | | | | + | CONFIDENTIAL | Current | RFC 5545, Section 3.8.1.3 | + +----------------+---------+---------------------------+ + + + + +Desruisseaux Standards Track [Page 162] + +RFC 5545 iCalendar September 2009 + + +8.3.12. Methods Registry + + No values are defined in this document for the "METHOD" property. + +9. Acknowledgments + + The editor of this document wishes to thank Frank Dawson and Derik + Stenerson, the original authors of RFC 2445, as well as the following + individuals who have participated in the drafting, review, and + discussion of this memo: + + Joe Abley, Hervey Allen, Steve Allen, Jay Batson, Oliver Block, + Stephane Bortzmeyer, Chris Bryant, Tantek Celik, Mark Crispin, Cyrus + Daboo, Mike Douglass, Andrew N. Dowden, Lisa Dusseault, Lars Eggert, + Gren Eliot, Pasi Eronen, Ben Fortuna, Ned Freed, Neal Gafter, Ted + Hardie, Tim Hare, Jeffrey Harris, Helge Hess, Paul B. Hill, Thomas + Hnetila, Russ Housley, Leif Johansson, Ciny Joy, Bruce Kahn, Reinhold + Kainhofer, Martin Kiff, Patrice Lapierre, Michiel van Leeuwen, + Jonathan Lennox, Jeff McCullough, Bill McQuillan, Alexey Melnikov, + John W. Noerenberg II, Chuck Norris, Mark Paterson, Simon Pilette, + Arnaud Quillaud, Robert Ransdell, Julian F. Reschke, Caleb + Richardson, Sam Roberts, Dan Romascanu, Mike Samuel, George Sexton, + Nigel Swinson, Clint Talbert, Simon Vaillancourt, Magnus Westerlund, + and Sandy Wills. + + A special thanks to the working group chairs Aki Niemi and Eliot Lear + for their support and guidance. + + The editor would also like to thank the Calendaring and Scheduling + Consortium for advice with this specification, and for organizing + interoperability testing events to help refine it. + + + + + + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 163] + +RFC 5545 iCalendar September 2009 + + +10. References + +10.1. Normative References + + [ISO.8601.2004] International Organization for + Standardization, "Data elements and + interchange formats -- Information interchange + -- Representation of dates and times", 2004. + + [ISO.9070.1991] International Organization for + Standardization, "Information Technology_SGML + Support Facilities -- Registration Procedures + for Public Text Owner Identifiers, Second + Edition", April 1991. + + [RFC2045] Freed, N. and N. Borenstein, "Multipurpose + Internet Mail Extensions (MIME) Part One: + Format of Internet Message Bodies", RFC 2045, + November 1996. + + [RFC2046] Freed, N. and N. Borenstein, "Multipurpose + Internet Mail Extensions (MIME) Part Two: + Media Types", RFC 2046, November 1996. + + [RFC2119] Bradner, S., "Key words for use in RFCs to + Indicate Requirement Levels", BCP 14, + RFC 2119, March 1997. + + [RFC2368] Hoffman, P., Masinter, L., and J. Zawinski, + "The mailto URL scheme", RFC 2368, July 1998. + + [RFC3629] Yergeau, F., "UTF-8, a transformation format + of ISO 10646", STD 63, RFC 3629, + November 2003. + + [RFC3986] Berners-Lee, T., Fielding, R., and L. + Masinter, "Uniform Resource Identifier (URI): + Generic Syntax", STD 66, RFC 3986, + January 2005. + + [RFC4288] Freed, N. and J. Klensin, "Media Type + Specifications and Registration Procedures", + BCP 13, RFC 4288, December 2005. + + [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 + Data Encodings", RFC 4648, October 2006. + + + + + +Desruisseaux Standards Track [Page 164] + +RFC 5545 iCalendar September 2009 + + + [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for + Syntax Specifications: ABNF", STD 68, + RFC 5234, January 2008. + + [RFC5646] Phillips, A., Ed., and M. Davis, Ed., "Tags + for Identifying Languages", BCP 47, RFC 5646, + September 2009. + + [US-ASCII] American National Standards Institute, "Coded + Character Set - 7-bit American Standard Code + for Information Interchange", ANSI X3.4, 1986. + +10.2. Informative References + + [2446bis] Daboo, C., "iCalendar Transport-Independent + Interoperability Protocol (iTIP)", Work + in Progress, April 2009. + + [2447bis] Melnikov, A., "iCalendar Message-Based + Interoperability Protocol (iMIP)", Work + in Progress, June 2008. + + [ANSI INCITS 61-1986] International Committee for Information + Technology, "Representation of Geographic + Point Locations for Information Interchange + (formerly ANSI X3.61-1986 (R1997))", ANSI + INCITS 61-1986 (R2007), 2007. + + [RFC1738] Berners-Lee, T., Masinter, L., and M. + McCahill, "Uniform Resource Locators (URL)", + RFC 1738, December 1994. + + [RFC2392] Levinson, E., "Content-ID and Message-ID + Uniform Resource Locators", RFC 2392, + August 1998. + + [RFC2397] Masinter, L., "The "data" URL scheme", + RFC 2397, August 1998. + + [RFC2425] Howes, T., Smith, M., and F. Dawson, "A MIME + Content-Type for Directory Information", + RFC 2425, September 1998. + + [RFC2426] Dawson, F. and T. Howes, "vCard MIME Directory + Profile", RFC 2426, September 1998. + + + + + + +Desruisseaux Standards Track [Page 165] + +RFC 5545 iCalendar September 2009 + + + [RFC2445] Dawson, F. and Stenerson, D., "Internet + Calendaring and Scheduling Core Object + Specification (iCalendar)", RFC 2445, + November 1998. + + [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, + H., Masinter, L., Leach, P., and T. Berners- + Lee, "Hypertext Transfer Protocol -- + HTTP/1.1", RFC 2616, June 1999. + + [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, + May 2000. + + [RFC4516] Smith, M. and T. Howes, "Lightweight Directory + Access Protocol (LDAP): Uniform Resource + Locator", RFC 4516, June 2006. + + [RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault, + "Calendaring Extensions to WebDAV (CalDAV)", + RFC 4791, March 2007. + + [TZDB] Eggert, P. and A.D. Olson, "Sources for Time + Zone and Daylight Saving Time Data", + July 2009, + . + + [VCAL] Internet Mail Consortium, "vCalendar: The + Electronic Calendaring and Scheduling Exchange + Format", September 1996, + . + + + + + + + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 166] + +RFC 5545 iCalendar September 2009 + + +Appendix A. Differences from RFC 2445 + + This appendix contains a list of changes that have been made in the + Internet Calendaring and Scheduling Core Object Specification from + RFC 2445. + +A.1. New Restrictions + + 1. The "DTSTART" property SHOULD be synchronized with the recurrence + rule, if specified. + + 2. The "RRULE" property SHOULD NOT occur more than once in a + component. + + 3. The BYHOUR, BYMINUTE, and BYSECOND rule parts MUST NOT be + specified in the "RRULE" property when the "DTSTART" property is + specified as a DATE value. + + 4. The value type of the "DTEND" or "DUE" properties MUST match the + value type of "DTSTART" property. + + 5. The "DURATION" property can no longer appear in "VFREEBUSY" + components. + +A.2. Restrictions Removed + + 1. The "DTSTART" and "DTEND" properties are no longer required to be + specified as date with local time and time zone reference when + used with a recurrence rule. + +A.3. Deprecated Features + + 1. The "EXRULE" property can no longer be specified in a component. + + 2. The "THISANDPRIOR" value can no longer be used with the "RANGE" + parameter. + + 3. The "PROCEDURE" value can no longer be used with the "ACTION" + property. + + 4. The value type RECUR no longer allows multiple values to be + specified by a COMMA-separated list of values. + + 5. x-name rule parts can no longer be specified in properties of + RECUR value type (e.g., "RRULE"). x-param can be used on RECUR + value type properties instead. + + + + + +Desruisseaux Standards Track [Page 167] + +RFC 5545 iCalendar September 2009 + + +Author's Address + + Bernard Desruisseaux (editor) + Oracle Corporation + 600 blvd. de Maisonneuve West + Suite 1900 + Montreal, QC H3A 3J2 + CANADA + + EMail: bernard.desruisseaux@oracle.com + URI: http://www.oracle.com/ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Desruisseaux Standards Track [Page 168] +