如何使用Flask和flask_jwt_extended进行自定义JWT验证？

pip install Flask flask_jwt_extended

from flask import Flask
from flask_jwt_extended import JWTManager, jwt_required, create_access_token, get_jwt_identity

app = Flask(__name__)
app.config['JWT_SECRET_KEY'] = 'your-secret-key'  # 设置JWT的密钥，用于签名
jwt = JWTManager(app)

@jwt.user_loader_callback_loader
def user_loader_callback(identity):
    # 在这里实现自定义的用户加载逻辑，例如从数据库中加载用户信息
    user = User.query.get(identity)
    return user

@app.route('/login', methods=['POST'])
def login():
    # 在这里实现用户登录逻辑，验证用户名和密码
    username = request.json.get('username')
    password = request.json.get('password')

    # 验证用户名和密码是否正确
    if username == 'admin' and password == 'password':
        # 生成JWT并返回给客户端
        access_token = create_access_token(identity=username)
        return {'access_token': access_token}, 200
    else:
        return {'message': 'Invalid username or password'}, 401

@app.route('/protected', methods=['GET'])
@jwt_required()  # 使用装饰器进行JWT验证
def protected():
    # 获取JWT中的用户身份信息
    current_user = get_jwt_identity()
    return {'message': f'Hello, {current_user}! This is a protected resource.'}, 200