django 1.3 requires something in auth_backends

apps/users/backends.py

@@ -22,3 +22,15 @@ def get_user(self, user_id):
             return User.objects.get(pk=user_id)
         except User.DoesNotExist:
             return None
+
+
+class NoAuthForYou(object):
+    """An authentication backend for read-only mode."""
+    supports_anonymous_user = False
+    supports_object_permissions = False
+
+    def authenticate(self, *args, **kw):
+        return None
+
+    def get_user(self, *args, **kw):
+        return None

settings.py

@@ -731,7 +731,7 @@ def read_only_mode(env):
     env['DATABASES']['default'] = env['DATABASES'][slave]
 
     # No sessions without the database, so disable auth.
-    env['AUTHENTICATION_BACKENDS'] = ()
+    env['AUTHENTICATION_BACKENDS'] = ('users.backends.NoAuthForYou',)
 
     # Add in the read-only middleware before csrf middleware.
     extra = 'amo.middleware.ReadOnlyMiddleware'