from flask import Flask
from flask import jsonify

from flask_jwt_extended import create_access_token
from flask_jwt_extended import jwt_required
from flask_jwt_extended import JWTManager

app = Flask(__name__)

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

# Set a callback function to return a custom response whenever an expired
# token attempts to access a protected route. This particular callback function
# takes the jwt_header and jwt_payload as arguments, and must return a Flask
# response. Check the API documentation to see the required argument and return
# values for other callback functions.
@jwt.expired_token_loader
def my_expired_token_callback(jwt_header, jwt_payload):
    return jsonify(code="dave", err="I can't let you do that"), 401

@app.route("/login", methods=["POST"])
def login():
    access_token = create_access_token("example_user")
    return jsonify(access_token=access_token)

@app.route("/protected", methods=["GET"])
@jwt_required()
def protected():
    return jsonify(hello="world")

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

@jwt.expired_token_loader
def my_expired_token_callback(jwt_header, jwt_payload):
    """返回 flask Response 格式"""
    return jsonify(code="401", err="token 已过期"), 401

GET http://127.0.0.1:5000/api/v1/userinfo HTTP/1.1
User-Agent: Fiddler
Host: 127.0.0.1:5000
Content-Type: application/json
Content-Length: 0
Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJmcmVzaCI6ZmFsc2UsImlhdCI6MTY2MTk1NzA2NiwianRpIjoiNmY4NWRlNGEtZThhNS00ZGY2LWJiMjktMmM4NWQyMWE3ZjU3IiwidHlwZSI6ImFjY2VzcyIsInN1YiI6InRlc3Q1IiwibmJmIjoxNjYxOTU3MDY2LCJleHAiOjE2NjE5NjA2NjZ9.GKsz2nJUziXLWfYrzidX7Fopw5tlycT0lZBKlvnpt8s

HTTP/1.1 401 UNAUTHORIZED
Server: Werkzeug/2.2.2 Python/3.8.5
Date: Thu, 01 Sep 2022 03:11:58 GMT
Content-Type: application/json
Content-Length: 48
Connection: close

{
  "code": "401",
  "err": "token 已过期"
}