from django.contrib import auth
from django.core.exceptions import ImproperlyConfigured
class LazyUser(object):
def __get__(self, request, obj_type=None):
if not hasattr(request, '_cached_user'):
from django.contrib.auth import get_user
request._cached_user = get_user(request)
return request._cached_user
class AuthenticationMiddleware(object):
def process_request(self, request):
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'."
request.__class__.user = LazyUser()
return None
class RemoteUserMiddleware(object):
"""
Middleware for utilizing web-server-provided authentication.
If request.user is not authenticated, then this middleware attempts to
authenticate the username passed in the ``REMOTE_USER`` request header.
If authentication is successful, the user is automatically logged in to
persist the user in the session.
The header used is configurable and defaults to ``REMOTE_USER``. Subclass
this class and change the ``header`` attribute if you need to use a
different header.
"""
# Name of request header to grab username from. This will be the key as
# used in the request.META dictionary, i.e. the normalization of headers to
# all uppercase and the addition of "HTTP_" prefix apply.
header = "REMOTE_USER"
def process_request(self, request):
# AuthenticationMiddleware is required so that request.user exists.
if not hasattr(request, 'user'):
raise ImproperlyConfigured(
"The Django remote user auth middleware requires the"
" authentication middleware to be installed. Edit your"
" MIDDLEWARE_CLASSES setting to insert"
" 'django.contrib.auth.middleware.AuthenticationMiddleware'"
" before the RemoteUserMiddleware class.")
try:
username = request.META[self.header]
except KeyError:
# If specified header doesn't exist then return (leaving
# request.user set to AnonymousUser by the
# AuthenticationMiddleware).
return
# If the user is already authenticated and that user is the user we are
# getting passed in the headers, then the correct user is already
# persisted in the session and we don't need to continue.
if request.user.is_authenticated():
if request.user.username == self.clean_username(username, request):
return
# We are seeing this user for the first time in this session, attempt
# to authenticate the user.
user = auth.authenticate(remote_user=username)
if user:
# User is valid. Set request.user and persist user in the session
# by logging the user in.
request.user = user
auth.login(request, user)
def clean_username(self, username, request):
"""
Allows the backend to clean the username, if the backend defines a
clean_username method.
"""
backend_str = request.session[auth.BACKEND_SESSION_KEY]
backend = auth.load_backend(backend_str)
try:
username = backend.clean_username(username)
except AttributeError: # Backend has no clean_username method.
pass
return username
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