@cto.af/http-headers

Parse HTTP headers from RFC 9110 using the full ABNF.

Installation

npm install @cto.af/http-headers

API

Example:

import {parse} from '@cto.af/http-headers';

// By default, the parser is strict about carriage-return/newline pairs.
const headers = parse('Date: Sun, 06 Nov 1994 08:49:37 GMT\r\n\r\n');
// [
//   {
//     kind: 'date',
//     value: 'Sun, 06 Nov 1994 08:49:37 GMT',
//     date: 1994-11-06T08:49:37.000Z,
//     name: 'Date'
//   }
// ]

// Rules named for a header (camel-case, with dashes turned into underscores)
// parse everything after the colon+whitespace for the specified header.
// Use the "startRule" option to select a specific header type.
const contentType = parse('text/html;charset=utf8', {startRule: 'Content_Type'});
// {
//   kind: 'content_type',
//   value: 'text/html;charset=utf8',
//   type: 'text',
//   subtype: 'html',
//   parameters: { charset: 'utf8' }
// }

// Unknown headers, or headers that had invalid values will have 'unknown: true'
// in their parsed version.
const unknownHeader = parse('Foo: bar=baz', {startRule: 'Header'});
// {
//   kind: 'foo',
//   name: 'Foo',
//   value: 'bar=baz',
//   unknown: true
// }

See the Peggy docs for more information on the parse function.

Here are the supported values for startRule:

• 'Headers': default
• 'Headers_Loose': Accept "\r\n" or "\n" at the end of lines
• 'Header': Any single header line
• 'Accept'
• 'Accept_Charset'
• 'Accept_Encoding'
• 'Accept_Language'
• 'Accept_Ranges'
• 'Age'
• 'Allow'
• 'ALPN'
• 'Alt_Svc'
• 'Authentication_Info'
• 'Authorization'
• 'Cache_Control'
• 'Connection'
• 'Content_Encoding'
• 'Content_Language'
• 'Content_Length'
• 'Content_Location'
• 'Content_Range'
• 'Content_Type'
• 'Date'
• 'ETag'
• 'Expect'
• 'Expires'
• 'From'
• 'Host'
• 'If_Match'
• 'If_Modified_Since'
• 'If_None_Match'
• 'If_Range'
• 'If_Unmodified_Since'
• 'Last_Modified'
• 'Location'
• 'Max_Forwards'
• 'Proxy_Authenticate'
• 'Proxy_Authentication_Info'
• 'Proxy_Authorization'
• 'Range'
• 'Referer'
• 'Retry_After'
• 'Server'
• 'Set_Cookie'
• 'Strict_Transport_Security'
• 'TE'
• 'Trailer'
• 'Upgrade'
• 'User_Agent'
• 'Vary'
• 'Via'
• 'WWW_Authenticate'
• 'Unknown_Header'

Development

To try a rule out without having to rebuild, do a variation of this:

curl -si --head https://github.com/ | \
  tail -n +2 | \
  node_modules/.bin/peggy src/index.peggy --format es -T- -S Headers_Loose

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