Django Integration

This page describes how authentication can be done using the Django web framework. Much of the library internals have been abstracted away so that Openid authentication can easily be plugged into django projects.

One of the goals of this integration is to be as unobtrusive as possible to existing django projects and to allow signing in (and registering) users into you django application via a single preconfigured OpenID-Connect Identity Provider.

Note

If you require a more sophisticated setup with multiple authentication backend that allow a user to associate and unassociate their different upstream accounts, use something like python-social-auth instead.

How it Works

To follow the design goal outlined above, the integration is implemented only using views, middlewares (optional) and a few database models. Inner workings of django or the authentication system are not changed by this integration, i.e. there are no additional authentication backends or custom user models.

The following models are added (relationships are visualized below):

  • OpenidUser which is the central tracking model for federated user data. It is linked to a projects user model and can be accessed by the openid property on the django user model.

  • OpenidSession to hold information relating to a concrete OpenID session. A single OpenID user can have multiple sessions, even on the same device. A session holds relevant tokens as well as expiry information.

┌───────────────────┐           ┌───────────────────┐           ┌───────────────────┐
│ Django User Model │           │ OpenidUser        │           │ OpenidSession     │
├───────────────────┤           ├───────────────────┤           ├───────────────────┤
│ username          │           │ sub               │     ╭┄┄N┄┄│ user              │
│ password          │     ╭┄┄1┄┄│ user              │     ┊     │ sid               │
│ …                 │     ┊     │ sessions          │┄┄1┄┄╯     │ scope             │
│ openid            │┄┄1┄┄╯     └───────────────────┘           │ access_token      │
└───────────────────┘                                           │ refresh_token     │
                                                                │ id_token          │
                                                                │ …                 │
                                                                └───────────────────┘

Logging In

When a user completes OpenID authentication via one of the routes provided by simple_openid_connect.integrations.django.urls (usually /auth/openid/login/), the information from the identity provider is saved in these models and the current django session is authenticated via a call to django.contrib.auth.login().

The login view also supports a ?next get parameter to influence where the user should be redirected after a successful login. If not specified, the LOGIN_REDIRECT_URL django setting is used.

Logging Out

When a user visits the logout endpoint (usually /auth/openid/logout/), the current django session is always immediately logged out via a call to django.contrib.auth.logout(). Afterwards, the user is redirected to the OpenID Identity Provider so that the logout intent can get federated through all OpenID connected apps. Unless the Identity Provider does something special, the user will return to the django app after this federated logout.

Setup

Add to INSTALLED_APPS

At first django settings need to be adapted to include simple_openid_connect.integrations.django as an app:

# settings.py
INSTALLED_APPS = [
    ...,
    "simple_openid_connect.integrations.django",
]

simple_openid_connect.integrations.django.TokenVerificationMiddleware should also be added to the middleware stack. This middleware makes sure that access tokens of users are still valid. It is not required if the library is only used as a Resource Server (see below):

# settings.py
MIDDLEWARE = [
    ...,
    "simple_openid_connect.integrations.django.middleware.TokenVerificationMiddleware",
]

Add url routes

Django needs to be told how to route Openid related login views. To do so, include this libraries urls into yours:

# urls.py
urlpatterns = [
    ...,
    path("auth/openid/", include("simple_openid_connect.integrations.django.urls")),
]

Required settings

These values must be set in the projects settings.py to configure openid authentication.

  • OPENID_ISSUER

    This settings configures the Openid issuer to use. This is required to be an https url and an Openid discovery document should be served under {issuer}/.well-known/openid-configuration.

  • OPENID_CLIENT_ID

    The client id that was issued to you from your Openid provider.

Settings Reference

For a list of all settings that are read by simple_openid_connect, see the SettingsModel.

Usage

After setup is done, this library is very hands off. It authenticates users using Openid-Connect, parses retrieved user information, automatically creates or updates user objects as required and then authenticates the current session. It interoperates with Django’s builtin authentication so things like the login_required decorator can still be used.

If you want to authenticate a user via Openid, simply visit /auth/openid/login on your app.

Note

Assuming, the URL setup from this documentation is followed, the following URLs are used by this integration:

Relative URL

Purpose

/auth/openid/login-callback/

Redirect-URI to which the user is returned to during login

/auth/openid/logout/frontchannel-notify/

Notification endpoint to which an Identity Provider may send Frontchannel Logout Notifications

Custom User Mapping

User objects are automatically created when the user authenticates to a django server using this integration. This is done when the server is a relying party as well as when it is a resource server. The goal is to be as transparent as possible to programmers because a user object is always available and associated with authenticated requests.

Sometimes it is useful though to customize the behavior in which tokens are mapped to users or which information is extracted from the tokens. This can be done in two steps:

  1. Subclass UserMapper and overwrite the methods which should be changed.

    For details about which methods exist on the class, what they should do and what their signatures are, take a look at the UserMapper class documentation.

    from simple_openid_connect.integrations.django.user_mapping import UserMapper

class CustomUserMapper(UserMapper):
    def automap_user_attrs(self, user, user_data):
        super().automap_user_attrs(user, user_data)
        if user_data.preferred_username == "admin":
            user.is_superuser = True
            user.is_staff = True

  2. Configure simple_openid_connect to use the new UserMapper class by setting the OPENID_USER_MAPPER attribute in your projects settings.py.

Accessing OpenidClient

If you ever need to do your own Openid interactions, a configured OpenidClient is available at this libraries AppConfig instance. You can access it like this:

from simple_openid_connect.integrations.django.apps import OpenidAppConfig
client = OpenidAppConfig.get_instance().get_client(request)

Logging into Django-Admin

Generally, because this integration does not replace the normal django authentication system, django-admin works normally and admin users can just use it as-is. The standard is_superuser property of user objects still controls who can access the page and you can influence how that property is set by defining a custom User Mapper as described above.

Sometimes though, for example if OpenID login is the only intended login method and accounts don’t have a password set, the Username & Password form rendered by django-admin can be a bit annoying. It can be changed by defining a custom template which overrides the relevant sections.

  1. Ensure your django app is loaded before django-admin:

    # settings.py
INSTALLED_APPS = [
    "my_awesome_app",
    ...
    "django.contrib.admin",
]

    This is needed because django searches through all installed apps for a given template name and you want to override the template provided by django-admin.

  2. Define your own admin/login.html template in your apps template directory. The example below does not completely overwrite the template provided by django-admin but instead extends it and only replaces the part which renders a login form. That way, all styles and themes are still applied correctly and the form looks consistent:

    {# my_awesome_app/templates/admin/login.html #}
{% extends "admin/login.html" %}
{% load i18n %}
{% block content %}
<div id="content-main">

{% if user.is_authenticated %}
<p class="errornote">
{% blocktranslate trimmed %}
    You are authenticated as {{ username }}, but are not authorized to
    access this page. Would you like to login to a different account?
{% endblocktranslate %}
</p>
{% endif %}

<form id="login-form" method="get" action="{% url 'simple_openid_connect:login' %}">
  <input hidden name="next" value="{{ request.GET.next | default:"/admin/" }}">
  <div class="submit-row">
    <input type="submit" value="{% translate 'Log in with OpenID Connect' %}">
  </div>
</form>

</div>
{% endblock %}

Clearing expired sessions

Depending on the OpenID Identity Provider, the federated sessions might be short lived and accumulate over time. To clear old and expired sessions, a django management command is provided. It can be run using the following command:

./manage.py clear-expired-openid-sessions

Resource Server Usage

If your app is not the one where a user is authenticated via Openid but instead one that accepts access tokens from authenticated user (e.g. an API server) you can still use this library. Using Django REST Framework is recommended but a plain django app can also be used as a resource server without it.

Access token validation is usually very simple and consists of asking the Openid provider if a given token is valid. This process is called token introspection and the provider may add more information about the token in its response (e.g. which scopes the token has access to).

Resource Server Configuration

There is almost no additional setup required when this library is used for resource servers. Settings like OPENID_ISSUER or client credentials are reused. The only exception is that the OPENID_REDIRECT_URI setting should be explicitly set to None if your project is exclusively acting as a resource server.

Verification using a client

A simple way to introspect a token is using an OpenidClient:

client = OpenidClient(...)
response = client.introspect_token(dummy_openid_provider.cheat_token)
assert response.active

Using the access_token_required decorator

If you are using Django, you can decorate your view functions with the access_token_required to enforce that only requests with a valid access token can access the view:

@access_token_required(required_scopes="openid my_resource:read")
def read_resource(request):
    ...