Working on: The Twitch authentication

auth.py

@@ -1,5 +1,6 @@
 import httpx
 import secrets
+import logging
 from fastapi import APIRouter, Depends, HTTPException, Request, Response
 from fastapi.responses import RedirectResponse
 from sqlalchemy.orm import Session
@@ -11,6 +12,9 @@ import security
 
 router = APIRouter()
 
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
 # Dependency to get a DB session
 def get_db():
     db = SessionLocal()
@@ -27,6 +31,7 @@ async def login_with_twitch(request: Request):
     # Generate a random state token for CSRF protection
     state = secrets.token_urlsafe(16)
     request.session['oauth_state'] = state
+    logger.info(f"Generated OAuth state: {state} for session.")
 
     # As per RESEARCH_REPORT.md, these are the minimum required scopes
     scopes = "chat:read"
@@ -48,7 +53,9 @@ async def auth_twitch_callback(code: str, state: str, request: Request, db: Sess
     Step 2 of OAuth flow: Handle the callback from Twitch after user authorization.
     """
     # CSRF Protection: Validate the state
-    if state != request.session.pop('oauth_state', None):
+    session_state = request.session.pop('oauth_state', None)
+    if state != session_state:
+        logger.error(f"OAuth state mismatch! Received state: '{state}', Session state: '{session_state}'")
         raise HTTPException(status_code=403, detail="Invalid state parameter. CSRF attack suspected.")
 
     # Step 4: Exchange the authorization code for an access token

main.py

@@ -65,13 +65,13 @@ async def lifespan(app: FastAPI):
 
 app = FastAPI(lifespan=lifespan)
 
-# Add middleware to trust proxy headers (X-Forwarded-For, X-Forwarded-Proto)
-# This is crucial for running behind a reverse proxy like Nginx or Caddy.
-app.add_middleware(ProxyHeadersMiddleware, trusted_hosts="*")
-
 # Add session middleware. A secret key is required for signing the session cookie.
 # We can reuse our encryption key for this, but in production you might want a separate key.
+# Note: Middleware is applied in reverse order (last added is first executed).
+# We want ProxyHeaders to run FIRST (outermost) to fix the scheme/host, 
+# then SessionMiddleware to run SECOND (inner) so it sees the correct scheme.
 app.add_middleware(SessionMiddleware, secret_key=settings.ENCRYPTION_KEY)
+app.add_middleware(ProxyHeadersMiddleware, trusted_hosts="*")
 
 # Mount the 'static' directory using an absolute path for reliability
 # This MUST be done before the routes that depend on it are defined.