Backend App Development

This document details instructions and guidelines for developing backend apps to be used with the SODAR Core framework.

It is recommended to read Project App Development before this document.

Backend App Basics

Backend apps are intended as apps used by other apps via their plugin, without requiring hard-coded imports. These may provide their own views for e.g. Ajax API functionality, but mostly they’re intended to be internal (hence the name).


See Project App Development.


No specific model implementation is required. However, it is strongly to refer to objects using sodar_uuid fields instead of the database private key.


The plugin is detected and retrieved using a BackendAppPlugin.

Declaring the Plugin

Create a file in your app’s directory. In the file, declare a BackendAppPlugin class implementing projectroles.plugins.BackendPluginPoint. Within the class, implement member variables and functions as instructed in comments and docstrings.

from projectroles.plugins import BackendPluginPoint
from .urls import urlpatterns

class BackendAppPlugin(BackendPluginPoint):
    """Plugin for registering a backend app"""
    name = 'example_backend_app'
    title = 'Example Backend App'
    urls = urlpatterns
    # ...

The following variables and functions are mandatory:

  • name: App name (ideally should correspond to the app package name)

  • title: Printable app title

  • icon: Font Awesome 4.7 icon name (without the fa-* prefix)

  • description: Verbose description of app

  • get_api(): Function for retrieving the API class for the backend, to be implemented

Implementing the following is optional:

  • javascript_url: Path to on demand includeable Javascript file

  • css_url: Path to on demand includeable CSS file

  • get_statistics(): Return statistics for the siteinfo app. See details in the siteinfo documentation.


If you want to implement a backend API which is closely tied to a project app, there’s no requirement to declare your backend as a separate Django app. You can just include the BackendAppPlugin in your app’s along with your ProjectAppPlugin. See the timeline app for an example of this.

Using the Plugin

To retrieve the API for the plugin, use the function projectroles.plugins.get_backend_api() as follows:

from projectroles.plugins import get_backend_api
example_api = get_backend_api('example_backend_app')

if example_api:     # Make sure the API is there, and only after that..
    pass            # stuff with the API

Including Backend Javascript/CSS

If you want Javascript or CSS files to be associated with your plugin you can set the javascript_url or css_url variables to specify the path to your file. Note that these should correspond to STATIC paths under your app directory.

class BackendPlugin(BackendPluginPoint):

    name = 'example_backend_app'
    title = 'Example Backend App'
    javascript_url = 'example_backend_app/js/example.js'
    css_url = 'example_backend_app/css/example.css'

The get_backend_include template-tag will return a <script> or <link> html tag with your specific file path, to be used in a template of your app making use of the backend plugin:

{% load projectroles_common_tags %}
{% get_backend_include 'example_backend_app' 'js' as javascript_include_tag %}
{{ javascript_include_tag|safe }}

{% get_backend_include 'example_backend_app' 'css' as css_include_tag %}
{{ css_include_tag|safe }}

This will result in the following HTML:

<script type="text/javascript" src="/static/example.js"></script>
<link rel="stylesheet" type="text/css" href="/static/example.css"/>

Be sure to use the backend plugin’s name (not the title) as the key and filter the result by safe, so the tag won’t be auto-escaped.