Backend query remodel: Phase 1 (N+1 + write explosion) + Phase 2 (CourseAssignment)

config/api_router.py

@@ -48,7 +48,9 @@
 
 assignments_router = nested_cls(courses_router, "assignments", lookup="assignment")
 assignments_router.register("submissions", SubmissionViewSet)
-assignments_router.register("activity-progress", ActivityProgressViewSet, basename="activity-progress")
+assignments_router.register(
+    "activity-progress", ActivityProgressViewSet, basename="activity-progress"
+)
 
 attachments_router = nested_cls(assignments_router, "submissions", lookup="submission")
 attachments_router.register("attachments", AttachmentViewSet)

config/settings/railway.py

@@ -16,8 +16,7 @@
 
 # Allow Railway's domain and custom domains
 ALLOWED_HOSTS = env.list(
-    "DJANGO_ALLOWED_HOSTS",
-    default=["localhost", ".railway.app", ".up.railway.app"]
+    "DJANGO_ALLOWED_HOSTS", default=["localhost", ".railway.app", ".up.railway.app"]
 )
 
 # DATABASES
@@ -62,7 +61,9 @@
 # STATIC FILES (whitenoise)
 # ------------------------------------------------------------------------------
 INSTALLED_APPS = ["whitenoise.runserver_nostatic"] + INSTALLED_APPS  # noqa F405
-MIDDLEWARE.insert(1, "whitenoise.middleware.WhiteNoiseMiddleware")  # After SecurityMiddleware
+MIDDLEWARE.insert(
+    1, "whitenoise.middleware.WhiteNoiseMiddleware"
+)  # After SecurityMiddleware
 
 STATICFILES_STORAGE = "whitenoise.storage.CompressedManifestStaticFilesStorage"
 STATIC_URL = "/static/"
@@ -79,12 +80,10 @@
 # ------------------------------------------------------------------------------
 # Use console backend for development/testing (emails print to console)
 EMAIL_BACKEND = env(
-    "DJANGO_EMAIL_BACKEND",
-    default="django.core.mail.backends.console.EmailBackend"
+    "DJANGO_EMAIL_BACKEND", default="django.core.mail.backends.console.EmailBackend"
 )
 DEFAULT_FROM_EMAIL = env(
-    "DJANGO_DEFAULT_FROM_EMAIL",
-    default="MusicCPR <noreply@musiccpr.org>"
+    "DJANGO_DEFAULT_FROM_EMAIL", default="MusicCPR <noreply@musiccpr.org>"
 )
 
 # ADMIN
@@ -97,9 +96,7 @@
     "version": 1,
     "disable_existing_loggers": False,
     "formatters": {
-        "verbose": {
-            "format": "%(levelname)s %(asctime)s %(name)s %(message)s"
-        }
+        "verbose": {"format": "%(levelname)s %(asctime)s %(name)s %(message)s"}
     },
     "handlers": {
         "console": {
@@ -133,17 +130,13 @@
         r"^https://.*\.railway\.app$",
         r"^http://localhost:\d+$",
         r"^http://127\.0\.0\.1:\d+$",
-    ]
+    ],
 )
 
 # Also allow specific origins if set
-CORS_ALLOWED_ORIGINS = env.list(
-    "CORS_ALLOWED_ORIGINS",
-    default=[]
-)
+CORS_ALLOWED_ORIGINS = env.list("CORS_ALLOWED_ORIGINS", default=[])
 
 # CSRF trusted origins (needed for admin)
 CSRF_TRUSTED_ORIGINS = env.list(
-    "CSRF_TRUSTED_ORIGINS",
-    default=["https://*.railway.app", "https://*.vercel.app"]
+    "CSRF_TRUSTED_ORIGINS", default=["https://*.railway.app", "https://*.vercel.app"]
 )

config/urls.py

@@ -15,6 +15,7 @@
 def debug_media(request):
     """Diagnostic endpoint to check media files."""
     import subprocess
+
     result = {
         "MEDIA_ROOT": str(settings.MEDIA_ROOT),
         "MEDIA_ROOT_exists": os.path.exists(settings.MEDIA_ROOT),
@@ -29,7 +30,9 @@ def debug_media(request):
                 for f in filenames[:20]:  # Limit to first 20
                     files.append(os.path.join(root, f).replace(settings.MEDIA_ROOT, ""))
             result["files"] = files
-            result["file_count"] = sum(len(f) for _, _, f in os.walk(settings.MEDIA_ROOT))
+            result["file_count"] = sum(
+                len(f) for _, _, f in os.walk(settings.MEDIA_ROOT)
+            )
         except Exception as e:
             result["error"] = str(e)
     else:
@@ -39,10 +42,13 @@ def debug_media(request):
     teleband_media = os.path.join(os.getcwd(), "teleband", "media")
     result["teleband_media_exists"] = os.path.exists(teleband_media)
     if os.path.exists(teleband_media):
-        result["teleband_media_count"] = sum(len(f) for _, _, f in os.walk(teleband_media))
+        result["teleband_media_count"] = sum(
+            len(f) for _, _, f in os.walk(teleband_media)
+        )
 
     return JsonResponse(result)
 
+
 urlpatterns = [
     path("", TemplateView.as_view(template_name="pages/home.html"), name="home"),
     path("debug-media/", debug_media, name="debug-media"),
@@ -68,9 +74,11 @@ def debug_media(request):
 # Serve media files - in production with S3 this is handled by S3,
 # but for Railway/local deployments we serve from filesystem
 # Note: static() only works with DEBUG=True, so we use serve() directly for non-S3 deployments
-if not hasattr(settings, 'DEFAULT_FILE_STORAGE') or 'S3' not in getattr(settings, 'DEFAULT_FILE_STORAGE', ''):
+if not hasattr(settings, "DEFAULT_FILE_STORAGE") or "S3" not in getattr(
+    settings, "DEFAULT_FILE_STORAGE", ""
+):
     urlpatterns += [
-        re_path(r'^media/(?P<path>.*)$', serve, {'document_root': settings.MEDIA_ROOT}),
+        re_path(r"^media/(?P<path>.*)$", serve, {"document_root": settings.MEDIA_ROOT}),
     ]
 
 if settings.DEBUG: