Authentication using REMOTE_USER

This document describes how to make use of external authentication sources (where the Web server sets the REMOTE_USER environment variable) in your Django applications. This type of authentication solution is typically seen on intranet sites, with single sign-on solutions such as IIS and Integrated Windows Authentication or Apache and mod_authnz_ldap, CAS, Cosign, WebAuth, mod_auth_sspi, etc.

When the Web server takes care of authentication it typically sets the REMOTE_USER environment variable for use in the underlying application. In Django, REMOTE_USER is made available in the request.META attribute. Django can be configured to make use of the REMOTE_USER value using the RemoteUserMiddleware and RemoteUserBackend classes found in django.contrib.auth.

Configuration

First, you must add the django.contrib.auth.middleware.RemoteUserMiddleware to the MIDDLEWARE_CLASSES setting after the django.contrib.auth.middleware.AuthenticationMiddleware:

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

Next, you must replace the ModelBackend with RemoteUserBackend in the AUTHENTICATION_BACKENDS setting:

AUTHENTICATION_BACKENDS = (
    'django.contrib.auth.backends.RemoteUserBackend',
)

With this setup, RemoteUserMiddleware will detect the username in request.META['REMOTE_USER'] and will authenticate and auto-login that user using the RemoteUserBackend.

Note

Since the RemoteUserBackend inherits from ModelBackend, you will still have all of the same permissions checking that is implemented in ModelBackend.

If your authentication mechanism uses a custom HTTP header and not REMOTE_USER, you can subclass RemoteUserMiddleware and set the header attribute to the desired request.META key. For example:

from django.contrib.auth.middleware import RemoteUserMiddleware

class CustomHeaderMiddleware(RemoteUserMiddleware):
    header = 'HTTP_AUTHUSER'

RemoteUserBackend

class django.contrib.auth.backends.RemoteUserBackend

If you need more control, you can create your own authentication backend that inherits from RemoteUserBackend and overrides certain parts:

Attributes

RemoteUserBackend.create_unknown_user

True or False. Determines whether or not a User object is created if not already in the database. Defaults to True.

Methods

RemoteUserBackend.clean_username(username)

Performs any cleaning on the username (e.g. stripping LDAP DN information) prior to using it to get or create a User object. Returns the cleaned username.

RemoteUserBackend.configure_user(user)

Configures a newly created user. This method is called immediately after a new user is created, and can be used to perform custom setup actions, such as setting the user's groups based on attributes in an LDAP directory. Returns the user object.

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