Linked Events

TL;DR => Linked Events is a REST API which allows you to set up an event* publication hub.

*event here means a happening where people get together and do something.

Linked Events is event information:

• Aggregator => using Python importers which have the logic to import events information from different data sources
• Creator => by offering PUT/POST /event API endpoint with granular user permissions and a hierarchical organization structure supporting different publishing rights for different organizations
• Publisher => by offering API endpoints from which interested parties can retrieve information about events

Linked Events was originally developed for City of Helsinki organization and you can see the Linked Events API in action for Helsinki capital region here. It contains data from all Helsinki City Departments as well as data from Helsinki Marketing and the Helmet metropolitan area public libraries. Viewing the API should give a reasonable view for the kind of information Linked Events is targeted for.

Target audience of this README.md are developers who may or maynot have a lot of Python experience and would like to get things running as quickly as possible. Therefore, instructions written in this README.md should be written accordingly.

Contributing

The best way to contribute is to open a new PR for discussion. We strive to be able to support various cities with various use cases, so suggestions and new features (as long as they fit in with existing functionality) are welcome.

Manual installation of Linked Events on physical or virtual machine:

Install following packages with your distros package manager

postgresql postgis nginx virtualenv python3-dev python3-pip build-essential libpq-dev

Preparing your PostgreSQL:

Generate required locales

sudo locale-gen fi_FI.UTF-8
sudo systemctl restart postgresql

Create a new role in postgresql

sudo -u postgres createuser -R -S linkedevents

Create a new database in postgresql

sudo -u postgres createdb -O linkedevents -T template0 -l fi_FI.UTF-8 linkedevents

Create extensions for the database

sudo -u postgres psql linkedevents -c "CREATE EXTENSION postgis;"
sudo -u postgres psql linkedevents -c "CREATE EXTENSION hstore;"

Preparing your local repository:

Clone your repository

git clone https://github.com/City-of-Turku/linkedevents.git

Create a virtual environment for your python

virtualenv -p python3 venv

Activate your virtual environment

source venv/bin/activate

Install requirements.txt

pip install -r requirements.txt

Install requirements-dev.txt

pip install -r requirements-dev.txt

Fill your database with included migrations:

Run basic migrations

python manage.py migrate

Additional changes to language fields according to settings.LANGUAGES

python manage.py sync_translation_fields

After this you have a very basic installation of Linked Events ready, but it's recommended to run at least some of the supported importers if you want to have all of the features working.

Use importers to add installation specific data:

#YSO(General Finnish Ontology)-importer that adds all the concepts and their alt labels and hierarchies.
#A large part of Linked Events features are built on top of YSO, this importer should be used in all installations.
python manage.py event_import ontology

#TSL-wordlist(Turun sanalista)-importer adds a City-of-Turku specific wordlist that is used by some of the keyword set importers.
#Use this if you don't plan on using your own keyword sets based on YSO or your own wordlists.
python manage.py event_import tsl --all

  #Add a new keyword set to display in the UI general audience selection.
  #!Based on TSL-wordlist so import that first!
  python manage.py add_tku_audience

  #Add a new keyword set to display in the UI event category selections.
  #!Based on TSL-wordlist so import that first!
  python manage.py add_tku_topics_by_content

  #Add a new keyword set to display in the UI event category selections.
  #!Based on TSL-wordlist so import that first!
  python manage.py add_tku_topics_by_type
  
  #Add a new keyword set to display in the UI hobby category selections.
  #!Based on TSL-wordlist so import that first!
  python manage.py add_tku_hobbytopics

  #Add a new keyword set to display in the UI course category selections.
  #!Based on TSL-wordlist so import that first!
  python manage.py add_tku_coursetopics

#Import TPR place data from Turku Servicemap API.
#It's recommended to use at least one of the place importers when developing Linked Events.
python manage.py event_import palvelukartta_units

#Import PTV/OSM place data from Lounaistieto API.
#It's recommended to use at least one of the place importers when developing Linked Events.
python manage.py event_import lounaistieto_units

#Import all Southwest Finland-region street addresses from Turku Servicemap API.
#It's recommended to use at least one of the place importers when developing Linked Events.
#!This importer adds an immense amount of place data to the database, so running it can take 12+ hours.
python manage.py event_import osoite --places

#Import City of Turku hierarchical organization for UI user rights management
python manage.py event_import turku_organization

#Add default payment methods to display in the UI.
python manage.py event_import payment_method_defaults
				
#Import Turku specific images for Linked Events image bank.
#! Before importing, create media\images folder in the main project folder
python manage.py event_import turku_image_bank
		
#Import event data from the old Turku events calendar.
python manage.py event_import turku_old_events --events

#Import default frontend sidefield help texts in three languages: Finnish, Swedish, English".
python manage.py event_import helptexts

Populating Search Columns

The Place model contains search columns for languages Finnish, Swedish and English. The columns contains lexems that are indexed as GIN indexes. These columns are used when searching in the Place model. The columns are populated with lexems in signals with the post_save signal or in the Osoite importer after all the addresses are imported. The population of search columns can also be run manually by running the following command.

python manage.py index_search_columns

Production notes

Development installation above will give you quite a serviceable production installation for lightish usage. You can serve out the application using your favorite WSGI-capable application server. The WSGI-entrypoint for Linked Events is linkedevents.wsgi or in file linkedevents/wsgi.py. Former is used by gunicorn, latter by uwsgi. The callable is application.

You will also need to serve out static and media folders at /static and /media in your URL space.

Running tests

Tests must be run using an user who can create (and drop) databases and write the directories your linkedevents installation resides in. Also the template database must include Postgis and HSTORE-extensions. If you are developing, you probably want to give those permissions to the database user configured in your development instance. Like so:

# Change this if you have different DB user
DATABASE_USER=linkedevents
# Most likely you have a postgres system user that can log into postgres as DB postgres user
sudo -u postgres psql << EOF
ALTER USER "$DATABASE_USER" CREATEDB;
\c template1
CREATE EXTENSION IF NOT EXISTS postgis;
CREATE EXTENSION IF NOT EXISTS hstore;
EOF

Afterwards you can run the tests:

cd $INSTALL_BASE/linkedevents
py.test events

Note that search tests will fail unless you configure search

Requirements

Linked Events uses two files for requirements. The workflow is as follows.

requirements.txt is not edited manually, but is generated with pip-compile.

requirements.txt always contains fully tested, pinned versions of the requirements. requirements.in contains the primary, unpinned requirements of the project without their dependencies.

In production, deployments should always use requirements.txt and the versions pinned therein. In development, new virtualenvs and development environments should also be initialised using requirements.txt. pip-sync will synchronize the active virtualenv to match exactly the packages in requirements.txt.

In development and testing, to update to the latest versions of requirements, use the command pip-compile. You can use requires.io to monitor the pinned versions for updates.

To remove a dependency, remove it from requirements.in, run pip-compile and then pip-sync. If everything works as expected, commit the changes.

Event extensions

It is possible to extend event data and API without touching events application by implementing separate extension applications. These extensions will be wired under field extension_<extension idenfier> in event API. If not auto enabled (see 6. below), extensions can be enabled per request using query param extensions with comma separated identifiers as values, or all for enabling all the extensions.

To implement an extension:

1. Create a new Django application, preferably named extension_<unique identifier for the extension>.

2. If you need to add new data for events, implement that using model(s) in the extension application.

3. Inherit events.extensions.EventExtension and implement needed attributes and methods. See extensions.py for details.

4. Add event_extension: <your EventExtension subclass> attribute to the extension applications's AppConfig.

5. Make the extension available by adding the extension application to INSTALLED_APPS.

6. If you want to force the extension to be enabled on every request, add the extension's identifier to AUTO_ENABLED_EXTENSIONS in Django settings.

For an example extension implementation, see course extension.