pydantic_models.py

from typing import Union
from pydantic import BaseModel
from fastapi.security import OAuth2PasswordBearer
from fastapi import Depends, HTTPException, status
from jose import JWTError, jwt
from datetime import datetime, timedelta
from passlib.context import CryptContext
from users import users_db
from error_logger import logger
import os


class Token(BaseModel):
    access_token: str
    token_type: str


class TokenData(BaseModel):
    username: Union[str, None] = None


class User(BaseModel):
    username: str
    email: Union[str, None] = None
    full_name: Union[str, None] = None
    disabled: Union[bool, None] = None


class UserInDB(User):
    hashed_password: str


class Config:
    orm_mode = True


# to get a string like this run:
# openssl rand -hex 32
SECRET_KEY = os.getenv('SECRET_KEY')
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30


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

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


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


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


def get_user(db, username: str):
    if username in db:
        user_dict = db[username]
        return UserInDB(**user_dict)


def authenticate_user(user_db, username: str, password: str):
    user = get_user(user_db, username)
    if not user:
        return False
    if not verify_password(password, user.hashed_password):
        return False
    return user


def create_access_token(data: dict, expires_delta: Union[timedelta, None] = 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)):
    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])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        # credentials_exception
        logger.warning("Could not validate credentials")
        logger.error('Exception occurred', exc_info=True)
    user = get_user(users_db, username=token_data.username)
    if user is None:
        raise credentials_exception
    return user


async def get_current_active_user(current_user: User = Depends(get_current_user)):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user


# @app.post("/token", response_model=Token)
# async def login_for_access_token(form_data: OAuth2PasswordRequestForm = Depends()):
#    user = authenticate_user(users_db, form_data.username, form_data.password)
#    if not user:
#        raise HTTPException(
#            status_code=status.HTTP_401_UNAUTHORIZED,
#            detail="Incorrect username or password",
#            headers={"WWW-Authenticate": "Bearer"},
#        )
#    access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
#    access_token = create_access_token(
#        data={"sub": user.username}, expires_delta=access_token_expires
#    )
#    return {"access_token": access_token, "token_type": "bearer"}
#
#
# @app.get("/users/me/", response_model=User)
# async def read_users_me(current_user: User = Depends(get_current_active_user)):
#    if current_user.disabled:
#        raise HTTPException(status_code=400, detail="Inactive user")
#    return current_user