Creating a plugin

You can extend pretalx with custom Python code using the official plugin API. Think of every plugin as an independent Django application living in its own python package installed like any other python module.

The communication between pretalx and the plugins happens using Django’s signal dispatcher feature. The core modules of pretalx expose signals which you can read about on the next pages.

To create a new plugin, create a new python package which must be a valid Django application and must contain plugin meta-data, as described below. You will need some boilerplate for every plugin to get started. To save your time, we created a cookiecutter template that you can use like this:

(env)$ pip install cookiecutter
(env)$ cookiecutter https://github.com/pretalx/pretalx-plugin-cookiecutter

This will ask you some questions and then create a project folder for your plugin. Afterwards install your plugin into pretalx:

(env)$ cd pretalx-pluginname
(env)$ python -m pip install -e .

If you already had it running, you’ll now have to restart your pretalx development server process for it to recognise the new plugin.

About this Documentation

The following pages go into detail about the types of plugins supported. While these instructions don’t assume that you know a lot about pretalx, they do assume that you have prior knowledge about Django (e.g. its view layer, how its ORM works, topics covered in the Django tutorial.).

Plugin meta-data

The plugin meta-data lives inside a PretalxPluginMeta class inside your configuration class. The meta-data class must define the following attributes:

Attribute	Type	Description
name	string	The human-readable name of your plugin
author	string	Your name
version	string	A human-readable version code of your plugin
description	string	A more verbose description of what your plugin does.
category	string	A category for your plugin, used to group it in the plugin list. Supported categories are FEATURE, INTEGRATION, CUSTOMIZATION, EXPORTER, RECORDING, LANGUAGE, OTHER (default).

A working example would be:

from django.apps import AppConfig
from django.utils.translation import ugettext_lazy as _


class FacebookApp(AppConfig):
    name = "pretalx_facebook"
    verbose_name = _("Facebook")

    class PretalxPluginMeta:
        name = _("Facebook")
        author = _("the pretalx team")
        version = "1.0.0"
        visible = True
        restricted = False
        description = _("This plugin allows you to post talks to facebook.")
        category = "INTEGRATION"


default_app_config = "pretalx_facebook.FacebookApp"

Plugin registration

Somehow, pretalx needs to know that your plugin exists at all. For this purpose, we make use of the entry point feature of setuptools. To register a plugin that lives in a separate python package, your pyproject.toml should contain something like this:

[project.entry-points."pretalx.plugin"]
pretalx_facebook = "pretalx_facebook:PretalxPluginMeta"

This will automatically make pretalx discover this plugin as soon as you have installed it e.g. through pip. During development, you can run pip install -e . inside your plugin source directory to make it discoverable.

Signals

pretalx defines signals which your plugin can listen for. We will go into the details of the different signals in the following pages. We suggest that you put your signal receivers into a signals submodule of your plugin. You should extend your AppConfig (see above) by the following method to make your receivers available:

class PaypalApp(AppConfig):

    def ready(self):
        from . import signals  # noqa

You can optionally specify code that you want to execute when the organiser activates your plugin for an event in the installed method, and code to execute upon removal in the uninstalled method:

class PaypalApp(AppConfig):

    def installed(self, event):
        pass  # Your code here

    def uninstalled(self, event):
        pass  # Your code here

The AppConfig class may also implement the method is_available(event) which checks if a plugin is available for a specific event. If not, it will not be shown on the plugin list for that event, and cannot be enabled.

Views

Your plugin may define custom views. If you put an urls submodule into your plugin module, pretalx will automatically import it and include it into the root URL configuration with the namespace plugins:<label>:, where <label> is your Django application label.

Note

We recommend that non-backend-URLs start with a /p/ to avoid collisions with event names.

Warning

If you define custom URLs and views, you are on your own with checking that the calling user has logged in, has appropriate permissions, and more. We plan on providing native support for this in a later version.

Configuration

Occasionally, your plugin may need system-level configuration that does not need its own API. In this case, you can ask users to provide this configuration via their pretalx.cfg file. Ask them to put their configuration in a section with the title [plugin:your_plugin_name], which pretalx will then provide in settings.PLUGIN_SETTINGS[your_plugin_name], like this:

[plugin:pretalx_soap]
endpoint=https://example.com
api_key=123456

Which you can use in your code like this:

from django.conf import settings
assert settings.PLUGIN_SETTINGS["pretalx_soap"]["endpoint"] == "https://example.com"

Added in version 1.1: The PLUGIN_SETTINGS configuration was added in pretalx 1.1.