utils.py

from fastapi import Depends, HTTPException, status, Path
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt
from datetime import datetime, timedelta, date
from typing import Optional
from passlib.context import CryptContext
from sqlalchemy.orm import Session

import crud
from database import SessionLocal
from config import SECRET_KEY, ALGORITHM
from schemas import TokenData, User


admin_text_desc = 'Only for admin users'

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


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


def verify_password(plain_password: str, hashed_password: str):
    return pwd_context.verify(plain_password, hashed_password)


def get_password_hash(password: str):
    return pwd_context.hash(password)


def authenticate_user(email: str, password: str, db: Session):
    user = crud.get_user_by_email(db, email=email)
    if not user:
        return False
    if not verify_password(password, user.password):
        return False
    return user


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=15)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt


async def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        email: str = payload.get("sub")
        if email is None:
            raise credentials_exception
        token_data = TokenData(email=email)
    except JWTError:
        raise credentials_exception
    user = crud.get_user_by_email(db, email=token_data.email)
    if user is None:
        raise credentials_exception
    return user


def get_admin(user: User = Depends(get_current_user)):
    if user.is_admin:
        return True
    else:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail='Insufficient permissions')


def get_user(user_id: int = Path(..., ge=1), db: Session = Depends(get_db)) -> User:
    db_user = crud.get_user(db, user_id=user_id)
    if not db_user:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail='User not found')
    return db_user


def get_date(str_date: str) -> date:
    year, month, day = (int(x) for x in str_date.split('-'))
    return date(year, month, day)