from functools import partial
from urllib.parse import urlparse
from django.conf import settings
from django.contrib import auth
from django.contrib.auth import REDIRECT_FIELD_NAME, load_backend
from django.contrib.auth.backends import RemoteUserBackend
from django.contrib.auth.views import redirect_to_login
from django.core.exceptions import ImproperlyConfigured
from django.shortcuts import resolve_url
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
async def auser(request):
if not hasattr(request, "_acached_user"):
request._acached_user = await auth.aget_user(request)
return request._acached_user
class AuthenticationMiddleware(MiddlewareMixin):
def process_request(self, request):
if not hasattr(request, "session"):
raise ImproperlyConfigured(
"The Django authentication middleware requires session "
"middleware to be installed. Edit your MIDDLEWARE setting to "
"insert "
"'django.contrib.sessions.middleware.SessionMiddleware' before "
"'django.contrib.auth.middleware.AuthenticationMiddleware'."
)
request.user = SimpleLazyObject(lambda: get_user(request))
request.auser = partial(auser, request)
class LoginRequiredMiddleware(MiddlewareMixin):
"""
Middleware that redirects all unauthenticated requests to a login page.
Views using the login_not_required decorator will not be redirected.
"""
redirect_field_name = REDIRECT_FIELD_NAME
def process_view(self, request, view_func, view_args, view_kwargs):
if request.user.is_authenticated:
return None
if not getattr(view_func, "login_required", True):
return None
return self.handle_no_permission(request, view_func)
def get_login_url(self, view_func):
login_url = getattr(view_func, "login_url", None) or settings.LOGIN_URL
if not login_url:
raise ImproperlyConfigured(
"No login URL to redirect to. Define settings.LOGIN_URL or "
"provide a login_url via the 'django.contrib.auth.decorators."
"login_required' decorator."
)
return str(login_url)
def get_redirect_field_name(self, view_func):
return getattr(view_func, "redirect_field_name", self.redirect_field_name)
def handle_no_permission(self, request, view_func):
path = request.build_absolute_uri()
resolved_login_url = resolve_url(self.get_login_url(view_func))
# If the login url is the same scheme and net location then use the
# path as the "next" url.
login_scheme, login_netloc = urlparse(resolved_login_url)[:2]
current_scheme, current_netloc = urlparse(path)[:2]
if (not login_scheme or login_scheme == current_scheme) and (
not login_netloc or login_netloc == current_netloc
):
path = request.get_full_path()
return redirect_to_login(
path,
resolved_login_url,
self.get_redirect_field_name(view_func),
)
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):
"""
Allow 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):
"""
Remove 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