Token decode error exception handled

backend/main.py

@@ -10,7 +10,6 @@
 from pyinstrument import Profiler
 from sentry_sdk.integrations.asgi import SentryAsgiMiddleware
 from starlette.middleware.authentication import AuthenticationMiddleware
-
 from backend.config import settings
 from backend.db import db_connection
 from backend.exceptions import BadRequest, Conflict, Forbidden, NotFound, Unauthorized
@@ -55,16 +54,21 @@
     # Custom exception handler for invalid token and logout.
     @_app.exception_handler(HTTPException)
     async def custom_http_exception_handler(request: Request, exc: HTTPException):
-        if exc.status_code == 401 and "InvalidToken" in exc.detail.get("SubCode", ""):
-            return JSONResponse(
-                content={
-                    "Error": exc.detail["Error"],
-                    "SubCode": exc.detail["SubCode"],
-                },
-                status_code=exc.status_code,
-                headers={"WWW-Authenticate": "Bearer"},
-            )
-
+        try:
+            if exc.status_code == 401 and "InvalidToken" in exc.detail.get(
+                "SubCode", ""
+            ):
+                return JSONResponse(
+                    content={
+                        "Error": exc.detail["Error"],
+                        "SubCode": exc.detail["SubCode"],
+                    },
+                    status_code=exc.status_code,
+                    headers={"WWW-Authenticate": "Bearer"},
+                )
+        except Exception as e:
+            logging.debug(f"Exception while handling custom HTTPException: {e}")
+            pass
         if isinstance(exc.detail, dict) and "error" in exc.detail:
             error_response = exc.detail
         else:

backend/services/users/authentication_service.py

@@ -70,18 +70,18 @@ def verify_token(token):
 class TokenAuthBackend(AuthenticationBackend):
     async def authenticate(self, conn):
         if "authorization" not in conn.headers:
-            return
+            return None
 
         auth = conn.headers["authorization"]
         try:
             scheme, credentials = auth.split()
             if scheme.lower() != "token":
-                return
+                return None
             try:
                 decoded_token = base64.b64decode(credentials).decode("ascii")
             except UnicodeDecodeError:
                 logger.debug("Unable to decode token")
-                return False
+                return None
         except (ValueError, UnicodeDecodeError, binascii.Error):
             raise AuthenticationError("Invalid auth credentials")
 
@@ -90,7 +90,7 @@ async def authenticate(self, conn):
         )
         if not valid_token:
             logger.debug("Token not valid.")
-            return
+            return None
         tm.authenticated_user_id = user_id
         return AuthCredentials(["authenticated"]), SimpleUser(user_id)
 
@@ -251,7 +251,6 @@ async def login_required(
         raise AuthenticationError("Invalid auth credentials")
     valid_token, user_id = AuthenticationService.is_valid_token(decoded_token, 604800)
     if not valid_token:
-        logger.debug("Token not valid")
         raise HTTPException(
             status_code=status.HTTP_401_UNAUTHORIZED,
             detail={"Error": "Token is expired or invalid", "SubCode": "InvalidToken"},
@@ -275,12 +274,18 @@ async def login_required_optional(
             decoded_token = base64.b64decode(credentials).decode("ascii")
         except UnicodeDecodeError:
             logger.debug("Unable to decode token")
-            raise HTTPException(status_code=401, detail="Invalid token")
+            raise HTTPException(
+                status_code=status.HTTP_401_UNAUTHORIZED,
+                detail={
+                    "Error": "Token is expired or invalid",
+                    "SubCode": "InvalidToken",
+                },
+                headers={"WWW-Authenticate": "Bearer"},
+            )
     except (ValueError, UnicodeDecodeError, binascii.Error):
         raise AuthenticationError("Invalid auth credentials")
     valid_token, user_id = AuthenticationService.is_valid_token(decoded_token, 604800)
     if not valid_token:
-        logger.debug("Token not valid")
         return None
     return AuthUserDTO(id=user_id)