要在FastAPI中使用JWT进行身份验证，我们可以使用PyJWT库来生成和验证JWT令牌。以下是一个简单的示例代码，演示如何在FastAPI应用程序中使用JWT进行身份验证：
from fastapi import FastAPI, Depends, HTTPExceptionfrom fastapi.security import OAuth2PasswordBearerfrom jose import JWTError, jwtfrom passlib.context import CryptContextfrom datetime import datetime, timedeltaapp = FastAPI()# 加密算法SECRET_KEY = "your_secret_key"ALGORITHM = "HS256"ACCESS_TOKEN_EXPIRE_MINUTES = 30# 密码加密pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")# 用户数据模型users = { "user1": { "username": "user1", "password": "$2b$12$4QaMelDZ6p8H7bVz5H3RAuRfWFd2cE4VAUZd0nJ9H6p9BTJp6kQF6", # 加密后的密码为password "disabled": False }}# 生成JWT令牌def create_access_token(data: dict, expires_delta: 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# 验证JWT令牌def decode_access_token(token: str): try: payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM]) return payload except JWTError: raise HTTPException(status_code=401, detail="Invalid token")# 使用OAuth2PasswordBearer进行身份验证oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")# 身份验证路由@app.post("/token")async def login(form_data: dict = Depends(oauth2_scheme)): user = users.get(form_data["username"]) if user is None or not pwd_context.verify(form_data["password"], user["password"]): raise HTTPException(status_code=400, detail="Incorrect username or password") 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"}# 保护需要身份验证的路由@app.get("/protected")async def protected_route(token: str = Depends(oauth2_scheme)): payload = decode_access_token(token) username = payload.get("sub") user = users.get(username) if user is None: raise HTTPException(status_code=400, detail="User not found") return user在上面的示例中，我们首先定义了一个create_access_token函数来生成JWT令牌，然后定义了一个decode_access_token函数来验证JWT令牌。接着使用OAuth2PasswordBearer类来创建一个OAuth2密码验证方案。然后我们定义了一个登录路由/token来验证用户的用户名和密码，并生成JWT令牌。最后我们定义了一个受保护的路由/protected，使用Depends(oauth2_scheme)来进行身份验证。
请注意，以上示例仅作为演示目的，实际项目中可能需要根据需要进行更多的安全性配置和优化。
