Django identity.external middlewares

Set of middlewares to simplify consumption of external identity information in Web projects set up with Django Web framework.

identity.external.PersistentRemoteUserMiddlewareVar

When non-standard (different than REMOTE_USER) environment variable is used to pass information about externally authenticated user, this middleware can be used to customize the variable name without writing Python code.

For example, when consuming the information from some authentication HTTP proxy, HTTP request header values are passed as HTTP_-prefixed environment variables. If the authenticated user name is in X-Remote-User HTTP request header, it is available in HTTP_X_REMOTE_USER environment variable. Setting variable REMOTE_USER_VAR to HTTP_X_REMOTE_USER, for example with Apache HTTP Server directive

SetEnv REMOTE_USER_VAR HTTP_X_REMOTE_USER

and enabling identity.external.PersistentRemoteUserMiddlewareVar in MIDDLEWARE list after django.contrib.auth.middleware.AuthenticationMiddleware like

MIDDLEWARE = [
        ...
        'django.contrib.auth.middleware.AuthenticationMiddleware',
        'identity.external.PersistentRemoteUserMiddlewareVar',
        ...
]

will run django.contrib.auth.middleware.PersistentRemoteUserMiddleware with value from environment variable HTTP_X_REMOTE_USER.

identity.external.RemoteUserAttrMiddleware

When user is externally authenticated, for example via django.contrib.auth.middleware.RemoteUserMiddleware or django.contrib.auth.middleware.PersistentRemoteUserMiddleware, additional user attributes can be provided by the external authentication source.

This middleware will update user's email address, first and last name, and group membership in groups prefixed with ext: with information coming from environment variables

• REMOTE_USER_EMAIL
• REMOTE_USER_FIRSTNAME
• REMOTE_USER_LASTNAME
• REMOTE_USER_GROUP_N
• REMOTE_USER_GROUP_1, REMOTE_USER_GROUP_2, ...
• REMOTE_USER_GROUPS

where the REMOTE_USER prefix of these variables can be changed with the REMOTE_USER_VAR environment variable, just like with identity.external.PersistentRemoteUserMiddlewareVar.

The values are used verbating, as provided by Django. When REMOTE_USER_VALUES_ENCODING environment variable is set to base64url, the values are expected to be in this format and decoded to Unicode.

Users that are in external group admins (and thus get assigned to group ext:admins in Django) will also get the is_staff flag set and thus will be able to log in to the admin application.

The ext: prefixed groups have to be already created in Django database for the user membership to be updated in them.

In the MIDDLEWARE list, this middleware has to be listed after the authenticating middleware, for example

MIDDLEWARE = [
    ...
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.auth.middleware.PersistentRemoteUserMiddleware',
    'identity.external.RemoteUserAttrMiddleware',
    ...
]

See also

• External authentication for Django projects: https://www.adelton.com/django/external-authentication-for-django-projects Presentation at EuroPython 2015.