第七章 自定义装饰器

您可以创建自己的decorator来扩展此扩展所提供的decorator的功能。例如，您可能希望创建自己的decorator来验证JWT的存在，并验证此令牌具有足够的权限/角色来访问端点。在请求中验证令牌是一个函数列表，可以用来构建您自己的装饰器(这些也是这个扩展提供的所有默认装饰器在内部使用的)。
下面是一个例子。

from functools import wraps

from flask import Flask, jsonify, request
from flask_jwt_extended import (
    JWTManager, verify_jwt_in_request, create_access_token,
    get_jwt_claims
)

app = Flask(__name__)

app.config['JWT_SECRET_KEY'] = 'super-secret'  # Change this!
jwt = JWTManager(app)



# Here is a custom decorator that verifies the JWT is present in
# the request, as well as insuring that this user has a role of
# `admin` in the access token
def admin_required(fn):
    @wraps(fn)
    def wrapper(*args, **kwargs):
        verify_jwt_in_request()
        claims = get_jwt_claims()
        if claims['roles'] != 'admin':
            return jsonify(msg='Admins only!'), 403
        else:
            return fn(*args, **kwargs)
    return wrapper


@jwt.user_claims_loader
def add_claims_to_access_token(identity):
    if identity == 'admin':
        return {'roles': 'admin'}
    else:
        return {'roles': 'peasant'}


@app.route('/login', methods=['POST'])
def login():
    username = request.json.get('username', None)
    access_token = create_access_token(username)
    return jsonify(access_token=access_token)


@app.route('/protected', methods=['GET'])
@admin_required
def protected():
    return jsonify(secret_message="go banana!") 

if __name__ == '__main__':
    app.run()