How to authenticate using REMOTE_USERLink to this heading
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
or PersistentRemoteUserMiddleware, and
RemoteUserBackend classes found in
django.contrib.auth.
ConfigurationLink to this heading
First, you must add the
django.contrib.auth.middleware.RemoteUserMiddleware to the
MIDDLEWARE setting after the
django.contrib.auth.middleware.AuthenticationMiddleware:
MIDDLEWARE = [
'...',
'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.
Be aware that this particular setup disables authentication with the default
ModelBackend. This means that if the REMOTE_USER value is not set
then the user is unable to log in, even using Django’s admin interface.
Adding 'django.contrib.auth.backends.ModelBackend' to the
AUTHENTICATION_BACKENDS list will use ModelBackend as a fallback
if REMOTE_USER is absent, which will solve these issues.
Django’s user management, such as the views in contrib.admin and
the createsuperuser management command, doesn’t integrate with
remote users. These interfaces work with users stored in the database
regardless of AUTHENTICATION_BACKENDS.
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'
If you need more control, you can create your own authentication backend
that inherits from RemoteUserBackend and
override one or more of its attributes and methods.
Using REMOTE_USER on login pages onlyLink to this heading
The RemoteUserMiddleware authentication middleware assumes that the HTTP
request header REMOTE_USER is present with all authenticated requests. That
might be expected and practical when Basic HTTP Auth with htpasswd or
similar mechanisms are used, but with Negotiate (GSSAPI/Kerberos) or other
resource intensive authentication methods, the authentication in the front-end
HTTP server is usually only set up for one or a few login URLs, and after
successful authentication, the application is supposed to maintain the
authenticated session itself.
PersistentRemoteUserMiddleware
provides support for this use case. It will maintain the authenticated session
until explicit logout by the user. The class can be used as a drop-in
replacement of RemoteUserMiddleware
in the documentation above.