Shared authentication via secure domain cookies [1].

This module implements a simple single-sign-on mechanism based on secure cookies. On sites providing authentication, logged in users have a cookie set. This cookie is optionally encrypted with a shared secret. Sites consuming authentication can use the provided middleware to ensure that users are created and logged in automatically based on the presence of the cookie.

Signed cookies are enabled by default, but require django_signed from [2]. You'll need to ensure that all your sites have SECRET_KEY set to the same value.

In addition, if you're going to run multiple django instances on the same domain, you'll probably want to set your SESSION_COOKE_NAME, SESSION_COOKIE_DOMAIN or SESSION_COOKIE_PATH so they aren't all trying to use the same session.

1. https://github.com/easel/django-shared-auth
2. https://github.com/simonw/django-signed

To provide authentication: add the SharedAuthProviderMiddleware to MIDDLEWARE_CLASSES before the django AuthenticationMiddleware. You do not need to include the backend unless you're planning to also consume logins.

MIDDLEWARE_CLASSES = (
    ...
    'django_shared_auth.middleware.SharedAuthProviderMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    ...
)

To consume authentication: Add SharedAuthConsumerMiddleware to MIDDLEWARE_CLASSES after the django AuthenticationMiddleware.

MIDDLEWARE_CLASSES = (
    ...
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django_shared_auth.middleware.SharedAuthConsumerMiddleware',
    ...
)

Add the SharedAuthBackend to AUTHENTICATION_BACKENDS

AUTHENTICATION_BACKENDS = (
    'django.contrib.auth.backends.ModelBackend',
    'django_shared_auth.backends.SharedAuthBackend',
)