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from django.conf import settings
from django.contrib import auth
from django.contrib.auth import load_backend
from django.contrib.auth.backends import RemoteUserBackend
from django.core.exceptions import ImproperlyConfigured
from django.utils.deprecation import MiddlewareMixin
from django.utils.functional import SimpleLazyObject
def get_user(request):
if not hasattr(request, '_cached_user'):
request._cached_user = auth.get_user(request)
return request._cached_user
class AuthenticationMiddleware(MiddlewareMixin):
def process_request(self, request):
assert hasattr(request, 'session'), (
"The Django authentication middleware requires session middleware "
"to be installed. Edit your MIDDLEWARE%s setting to insert "
"'django.contrib.sessions.middleware.SessionMiddleware' before "
"'django.contrib.auth.middleware.AuthenticationMiddleware'."
) % ("_CLASSES" if settings.MIDDLEWARE is None else "")
request.user = SimpleLazyObject(lambda: get_user(request))
class SessionAuthenticationMiddleware(MiddlewareMixin):
"""
Formerly, a middleware for invalidating a user's sessions that don't
correspond to the user's current session authentication hash. However, it
caused the "Vary: Cookie" header on all responses.
It's now a shim to allow a single settings file to more easily support
multiple versions of Django. Will be RemovedInDjango20Warning.
"""
def process_request(self, request):
pass
class RemoteUserMiddleware(MiddlewareMixin):
"""
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"
force_logout_if_no_header = True
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 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 remove any existing
# authenticated remote-user, or return (leaving request.user set to
# AnonymousUser by the AuthenticationMiddleware).
if self.force_logout_if_no_header and request.user.is_authenticated:
self._remove_invalid_user(request)
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.get_username() == self.clean_username(username, request):
return
else:
# An authenticated user is associated with the request, but
# it does not match the authorized user in the header.
self._remove_invalid_user(request)
# We are seeing this user for the first time in this session, attempt
# to authenticate the user.
user = auth.authenticate(request, 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
def _remove_invalid_user(self, request):
"""
Removes the current authenticated user in the request which is invalid
but only if the user is authenticated via the RemoteUserBackend.
"""
try:
stored_backend = load_backend(request.session.get(auth.BACKEND_SESSION_KEY, ''))
except ImportError:
# backend failed to load
auth.logout(request)
else:
if isinstance(stored_backend, RemoteUserBackend):
auth.logout(request)
class PersistentRemoteUserMiddleware(RemoteUserMiddleware):
"""
Middleware for Web-server provided authentication on logon pages.
Like RemoteUserMiddleware but keeps the user authenticated even if
the header (``REMOTE_USER``) is not found in the request. Useful
for setups when the external authentication via ``REMOTE_USER``
is only expected to happen on some "logon" URL and the rest of
the application wants to use Django's authentication mechanism.
"""
force_logout_if_no_header = False