1+ from datetime import datetime , timedelta
2+ import jwt
3+ from fastapi import HTTPException , status , Depends
4+ from fastapi .security import OAuth2PasswordBearer
5+ from sqlalchemy .orm import Session
6+ 7+ from database import get_db
8+ from . import models , schemas
9+ from dotenv import load_dotenv
10+ 11+ load_dotenv ()
12+ SECRET_KEY = os .getenv ("JWT_SECRET_KEY" )
13+ 14+ oauth2_scheme = OAuth2PasswordBearer (tokenUrl = "token" )
15+ 16+ def create_access_token (data : dict , expires_delta : timedelta = timedelta (minutes = 15 )) -> str :
17+ """Generates a JWT access token for a user.
18+
19+ Args:
20+ data (dict): A dictionary containing user information to be encoded in the token.
21+ expires_delta (timedelta, optional): The expiration time for the token. Defaults to timedelta(minutes=15).
22+
23+ Returns:
24+ str: The encoded JWT access token.
25+ """
26+ to_encode = data .copy ()
27+ expire = datetime .utcnow () + expires_delta
28+ to_encode .update ({"exp" : expire })
29+ encoded_jwt = jwt .encode (to_encode , SECRET_KEY , algorithm = "HS256" )
30+ return encoded_jwt
31+ 32+ async def get_current_user (token : str = Depends (oauth2_scheme ), db : Session = Depends (get_db )) -> models .User :
33+ """Verifies the JWT token and retrieves the associated user from the database.
34+
35+ Args:
36+ token (str): The JWT token provided in the Authorization header.
37+ db (Session): The SQLAlchemy database session.
38+
39+ Returns:
40+ models.User: The user object associated with the token.
41+
42+ Raises:
43+ HTTPException: If the token is invalid, expired, or the user is not found.
44+ """
45+ try :
46+ payload = jwt .decode (token , SECRET_KEY , algorithms = ["HS256" ])
47+ user = db .query (models .User ).filter (models .User .email == payload ["sub" ]).first ()
48+ if not user :
49+ raise HTTPException (status_code = status .HTTP_401_UNAUTHORIZED , detail = "Invalid token" )
50+ return user
51+ except jwt .ExpiredSignatureError :
52+ raise HTTPException (status_code = status .HTTP_401_UNAUTHORIZED , detail = "Token expired" )
53+ except jwt .InvalidTokenError :
54+ raise HTTPException (status_code = status .HTTP_401_UNAUTHORIZED , detail = "Invalid token" )
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