oauth2.py

from turtle import settiltangle
from fastapi import Depends, status, HTTPException
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt
from datetime import datetime, timedelta
from . import schemas, database, models
from .config import settings
from sqlalchemy.orm import Session

oauth2_scheme = OAuth2PasswordBearer(tokenUrl='login')

# SECRET_KEY
# Algorithm
# Expriation Time
#========= hard code
# SECRET_KEY = "DFAS[OIH7&^BHGUSDT$#8TG$23!5609-_7879T(&79775vHhoh(*T%$4-%4"
# ALGORITHM = "HS256"
# ACCESS_TOKEN_EXPIRE_MINUTES = 60
SECRET_KEY = settings.secret_key
ALGORITHM = settings.algorithm
ACCESS_TOKEN_EXPIRE_MINUTES = settings.access_token_expire_minutes


def create_access_token(data: dict):
    to_encode = data.copy()
    
    expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire}) 
    
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    
    return encoded_jwt 


def verify_access_token(token: str, credentials_exception):
    
    try:
        # print(token)
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        id = payload.get("user_id")
        if id is None:
            raise credentials_exception
        token_data = schemas.TokenData(id=id)
    except JWTError as e:
        # print(e)        
        raise credentials_exception

    return token_data
    
def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(database.get_db)):
    credentials_exception = HTTPException(status_code = status.HTTP_401_UNAUTHORIZED,
                                             detail = f"Could not validate credentials", 
                                             headers = {"WWW-Authenticate": "Bearer"})
    
    token = verify_access_token(token, credentials_exception)
    
    user = db.query(models.User).filter(models.User.id == token.id).first()
    
    return user