JWT Authentication in FastAPI

Охватываемые темы: Installation, Configuration, Password and Token Utilities, Token Endpoint.

Installation

pip install python-jose[cryptography] passlib[bcrypt] python-multipart

Configuration

from datetime import datetime, timedelta
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm

SECRET_KEY = "your-secret-key"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30

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

Password and Token Utilities

def hash_password(password: str) -> str:
    return pwd_context.hash(password)

def verify_password(plain: str, hashed: str) -> bool:
    return pwd_context.verify(plain, hashed)

def create_access_token(data: dict, expires_delta: timedelta | None = None) -> str:
    to_encode = data.copy()
    expire = datetime.utcnow() + (expires_delta or timedelta(minutes=15))
    to_encode["exp"] = expire
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)

Token Endpoint

@router.post("/token")
def login(
    form_data: OAuth2PasswordRequestForm = Depends(),
    db: Session = Depends(get_session),
):
    user = db.exec(select(User).where(User.username == form_data.username)).first()
    if not user or not verify_password(form_data.password, user.hashed_password):
        raise HTTPException(status_code=401, detail="Invalid credentials")

    access_token = create_access_token(
        data={"sub": str(user.id)},
        expires_delta=timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES),
    )
    return {"access_token": access_token, "token_type": "bearer"}

Current User Dependency

def get_current_user(
    token: str = Depends(oauth2_scheme),
    db: Session = Depends(get_session),
) -> User:
    credentials_exception = HTTPException(status_code=401, detail="Invalid token")
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_id = payload.get("sub")
        if user_id is None:
            raise credentials_exception
    except JWTError:
        raise credentials_exception

    user = db.get(User, int(user_id))
    if user is None:
        raise credentials_exception
    return user

@app.get("/tasks/")
def list_tasks(current_user: User = Depends(get_current_user)):
    return db.query(Task).filter(Task.owner_id == current_user.id).all()