authentication

Authentication

Implement complete JWT authentication flow covering backend token generation, frontend auth state, Axios interceptors, and protected routes.

When to Use

• User needs to implement login/logout functionality
• User wants to protect routes requiring authentication
• User needs JWT token generation and validation (backend)
• User wants to add automatic token refresh
• User needs to set up Axios interceptors for auth headers

Available Operations

1. Create JWT token generation and validation (FastAPI backend)
2. Build login/logout flow with Zustand auth store
3. Set up Axios interceptors for automatic Bearer token headers
4. Implement protected route wrappers
5. Add refresh token rotation

Multi-Step Workflow

Step 1: Install Backend Dependencies

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

Step 2: Create JWT Token Utilities (Backend)

# src/auth/jwt.py
import os
from datetime import datetime, timedelta
from jose import jwt, JWTError
from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials

security = HTTPBearer()
SECRET_KEY = os.environ["JWT_SECRET"]
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE = timedelta(hours=1)
REFRESH_TOKEN_EXPIRE = timedelta(days=7)

def create_access_token(user_id: str) -> str:
    payload = {
        "sub": user_id,
        "exp": datetime.utcnow() + ACCESS_TOKEN_EXPIRE,
        "type": "access",
    }
    return jwt.encode(payload, SECRET_KEY, algorithm=ALGORITHM)

def create_refresh_token(user_id: str) -> str:
    payload = {
        "sub": user_id,
        "exp": datetime.utcnow() + REFRESH_TOKEN_EXPIRE,
        "type": "refresh",
    }
    return jwt.encode(payload, SECRET_KEY, algorithm=ALGORITHM)

async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
) -> User:
    try:
        payload = jwt.decode(credentials.credentials, SECRET_KEY, algorithms=[ALGORITHM])
        if payload.get("type") != "access":
            raise HTTPException(status_code=401, detail="Invalid token type")
        user = await user_repo.find_by_id(payload["sub"])
        if not user:
            raise HTTPException(status_code=401, detail="User not found")
        return user
    except JWTError:
        raise HTTPException(status_code=401, detail="Invalid token")