1 from django.contrib import auth

     2 from django.core.exceptions import ImproperlyConfigured

     3 

     4 

     5 class LazyUser(object):

     6     def __get__(self, request, obj_type=None):

     7         if not hasattr(request, '_cached_user'):

     8             from django.contrib.auth import get_user

     9             request._cached_user = get_user(request)

    10         return request._cached_user

    11 

    12 

    13 class AuthenticationMiddleware(object):

    14     def process_request(self, request):

    15         assert hasattr(request, 'session'), "The Django authentication middleware requires session middleware to be installed. Edit your MIDDLEWARE_CLASSES setting to insert 'django.contrib.sessions.middleware.SessionMiddleware'."

    16         request.__class__.user = LazyUser()

    17         return None

    18 

    19 

    20 class RemoteUserMiddleware(object):

    21     """

    22     Middleware for utilizing web-server-provided authentication.

    23 

    24     If request.user is not authenticated, then this middleware attempts to

    25     authenticate the username passed in the ``REMOTE_USER`` request header.

    26     If authentication is successful, the user is automatically logged in to

    27     persist the user in the session.

    28 

    29     The header used is configurable and defaults to ``REMOTE_USER``.  Subclass

    30     this class and change the ``header`` attribute if you need to use a

    31     different header.

    32     """

    33 

    34     # Name of request header to grab username from.  This will be the key as

    35     # used in the request.META dictionary, i.e. the normalization of headers to

    36     # all uppercase and the addition of "HTTP_" prefix apply.

    37     header = "REMOTE_USER"

    38 

    39     def process_request(self, request):

    40         # AuthenticationMiddleware is required so that request.user exists.

    41         if not hasattr(request, 'user'):

    42             raise ImproperlyConfigured(

    43                 "The Django remote user auth middleware requires the"

    44                 " authentication middleware to be installed.  Edit your"

    45                 " MIDDLEWARE_CLASSES setting to insert"

    46                 " 'django.contrib.auth.middleware.AuthenticationMiddleware'"

    47                 " before the RemoteUserMiddleware class.")

    48         try:

    49             username = request.META[self.header]

    50         except KeyError:

    51             # If specified header doesn't exist then return (leaving

    52             # request.user set to AnonymousUser by the

    53             # AuthenticationMiddleware).

    54             return

    55         # If the user is already authenticated and that user is the user we are

    56         # getting passed in the headers, then the correct user is already

    57         # persisted in the session and we don't need to continue.

    58         if request.user.is_authenticated():

    59             if request.user.username == self.clean_username(username, request):

    60                 return

    61         # We are seeing this user for the first time in this session, attempt

    62         # to authenticate the user.

    63         user = auth.authenticate(remote_user=username)

    64         if user:

    65             # User is valid.  Set request.user and persist user in the session

    66             # by logging the user in.

    67             request.user = user

    68             auth.login(request, user)

    69 

    70     def clean_username(self, username, request):

    71         """

    72         Allows the backend to clean the username, if the backend defines a

    73         clean_username method.

    74         """

    75         backend_str = request.session[auth.BACKEND_SESSION_KEY]

    76         backend = auth.load_backend(backend_str)

    77         try:

    78             username = backend.clean_username(username)

    79         except AttributeError: # Backend has no clean_username method.

    80             pass

    81         return username