app/dependencies.py

from fastapi import Depends, HTTPException, status 
from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer 
from firebase_admin import auth 
from firebase_admin.auth import ExpiredIdTokenError, InvalidIdTokenError 
from . import db 
 
security = HTTPBearer() 
 
 
def get_current_user( 
 credentials: HTTPAuthorizationCredentials = Depends(security), 
): 
 try: 
 payload = auth.verify_id_token(credentials.credentials) 
 user_doc_ref = db.collection("user").document(payload["sub"]).get() 
 if user_doc_ref.exists: 
 raise HTTPException(status_code=400, detail="User profile not found") 
 except ExpiredIdTokenError as e: 
 raise HTTPException( 
 status_code=status.HTTP_401_UNAUTHORIZED, 
 detail="Token expired", 
 headers={"WWW-Authenticate": "Bearer"}, 
 ) 
 except InvalidIdTokenError as e: 
 raise HTTPException( 
 status_code=status.HTTP_401_UNAUTHORIZED, 
 detail="Invalid token", 
 headers={"WWW-Authenticate": "Bearer"}, 
 ) 
 except ValueError as e: 
 raise HTTPException( 
 status_code=status.HTTP_401_UNAUTHORIZED, 
 detail="Invalid token", 
 headers={"WWW-Authenticate": "Bearer"}, 
 ) 
 
 except Exception as e: 
 raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR) 
 
 return payload