第四章 在JWT token中存储自定义数据

您可能希望在访问令牌（access token）中存储其他信息，并且这些信息可以在在受保护的视图中访问。以上需求可以使用user_claims_loader()装饰器实现，并可以使用get_jwt_claims()函数在受保护的端点中访问数据。
将数据存储在访问令牌中有助于提高性能。如果您将数据存储在令牌中，那么下次需要在受保护的端点中使用数据时，就不需要从磁盘查找数据。但是，您应该注意在令牌中放入了什么数据。任何能够读取令牌的人都可以轻松地查看访问令牌中的任何数据。不要在访问令牌中存储敏感信息(例如用户名和密码等)!

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

app = Flask(__name__)

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


# Using the user_claims_loader, we can specify a method that will be
# called when creating access tokens, and add these claims to the said
# token. This method is passed the identity of who the token is being
# created for, and must return data that is json serializable
@jwt.user_claims_loader
def add_claims_to_access_token(identity):
    return {
        'hello': identity,
        'foo': ['bar', 'baz']
    }


@app.route('/login', methods=['POST'])
def login():
    username = request.json.get('username', None)
    password = request.json.get('password', None)
    if username != 'test' or password != 'test':
        return jsonify({"msg": "Bad username or password"}), 401

    ret = {'access_token': create_access_token(username)}
    return jsonify(ret), 200


# In a protected view, get the claims you added to the jwt with the
# get_jwt_claims() method
@app.route('/protected', methods=['GET'])
@jwt_required
def protected():
    claims = get_jwt_claims()
    return jsonify({
        'hello_is': claims['hello'],
        'foo_is': claims['foo']
    }), 200


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