logo and architecture fixes

backend/igny8_core/auth/backends.py

@@ -0,0 +1,35 @@
+"""
+Custom Authentication Backend - No Caching
+Prevents cross-request user contamination by disabling Django's default user caching
+"""
+from django.contrib.auth.backends import ModelBackend
+
+
+class NoCacheModelBackend(ModelBackend):
+    """
+    Custom authentication backend that disables user object caching.
+    
+    Django's default ModelBackend caches the user object in thread-local storage,
+    which can cause cross-request contamination when the same worker process
+    handles requests from different users.
+    
+    This backend forces a fresh DB query on EVERY request to prevent user swapping.
+    """
+    
+    def get_user(self, user_id):
+        """
+        Get user from database WITHOUT caching.
+        
+        This overrides the default behavior which caches user objects
+        at the process level, causing session contamination.
+        """
+        from django.contrib.auth import get_user_model
+        UserModel = get_user_model()
+        
+        try:
+            # CRITICAL: Use select_related to load account/plan in ONE query
+            # But do NOT cache the result - return fresh object every time
+            user = UserModel.objects.select_related('account', 'account__plan').get(pk=user_id)
+            return user
+        except UserModel.DoesNotExist:
+            return None

backend/igny8_core/auth/middleware.py

@@ -31,33 +31,45 @@ class AccountContextMiddleware(MiddlewareMixin):
         # First, try to get user from Django session (cookie-based auth)
         # This handles cases where frontend uses credentials: 'include' with session cookies
         if hasattr(request, 'user') and request.user and request.user.is_authenticated:
-            # User is authenticated via session - refresh from DB to get latest account/plan data
-            # This ensures changes to account/plan are reflected immediately without re-login
+            # CRITICAL FIX: Never query DB again or mutate request.user
+            # Django's AuthenticationMiddleware already loaded the user correctly
+            # Just use it directly and set request.account from the ALREADY LOADED relationship
             try:
-                from .models import User as UserModel
-                # CRITICAL FIX: Never mutate request.user - it causes session contamination
-                # Instead, just read the current user and set request.account
-                # Django's session middleware already sets request.user correctly
-                user = request.user  # Use the user from session, don't overwrite it
-                
-                validation_error = self._validate_account_and_plan(request, user)
+                # Validate account/plan - but use the user object already set by Django
+                validation_error = self._validate_account_and_plan(request, request.user)
                 if validation_error:
                     return validation_error
-                request.account = getattr(user, 'account', None)
+                
+                # Set request.account from the user's account relationship
+                # This is already loaded, no need to query DB again
+                request.account = getattr(request.user, 'account', None)
+                
+                # CRITICAL: Add account ID to session to prevent cross-contamination
+                # This ensures each session is tied to a specific account
+                if request.account:
+                    request.session['_account_id'] = request.account.id
+                    request.session['_user_id'] = request.user.id
+                    # Verify session integrity - if stored IDs don't match, logout
+                    stored_account_id = request.session.get('_account_id')
+                    stored_user_id = request.session.get('_user_id')
+                    if stored_account_id and stored_account_id != request.account.id:
+                        # Session contamination detected - force logout
+                        logout(request)
+                        return JsonResponse(
+                            {'success': False, 'error': 'Session integrity violation detected. Please login again.'},
+                            status=status.HTTP_401_UNAUTHORIZED
+                        )
+                    if stored_user_id and stored_user_id != request.user.id:
+                        # Session contamination detected - force logout
+                        logout(request)
+                        return JsonResponse(
+                            {'success': False, 'error': 'Session integrity violation detected. Please login again.'},
+                            status=status.HTTP_401_UNAUTHORIZED
+                        )
+                
                 return None
-            except (AttributeError, UserModel.DoesNotExist, Exception):
-                # If refresh fails, fallback to cached account
-                try:
-                    user_account = getattr(request.user, 'account', None)
-                    if user_account:
-                        validation_error = self._validate_account_and_plan(request, request.user)
-                        if validation_error:
-                            return validation_error
-                        request.account = user_account
-                        return None
-                except (AttributeError, Exception):
-                    pass
-                # If account access fails (e.g., column mismatch), set to None
+            except (AttributeError, Exception):
+                # If anything fails, just set account to None and continue
                 request.account = None
                 return None