auth.py

from datetime import datetime, timedelta
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi import Depends, HTTPException
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.orm import Session
from db import SessionLocal
from models import *

SECRET_KEY = "super-secret-key"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 60

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="login")

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

def verify_password(plain, hashed):
    return pwd_context.verify(plain, hashed)

def hash_password(password):
    return pwd_context.hash(password)

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

def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)):
    credentials_exception = HTTPException(status_code=401, detail="Invalid credentials")

    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])

        username = payload.get("sub")
        if username is None:
            raise credentials_exception

        user = db.query(User).filter(User.username == username).first()
        if user is None:
            raise credentials_exception
        return user

    except JWTError:
        raise credentials_exception