Facebook chatbot应用测试订阅失败

Question

我一直在尝试逐步按照本指南（https://developers.facebook.com/docs/messenger-platform/getting-started/app-setup）进行一个简单的node js facebook chatbot。我已经使用curl和postman测试了后端，并且工作正常，我将Web应用程序订阅了webhook，但是一旦我从facebook.com或Messenger中向页面发送消息，Facebook就不会将消息发送到后端。我期望req.body.entry.messaging.message有一定的价值，但Facebook不会发送任何东西。

https://github.com/cristiantorresf/ChatBotLearning

'use strict';

// Imports dependencies and set up http server
const
  express = require('express'),
  bodyParser = require('body-parser'),
  app = express().use(bodyParser.json());
// token variable de entorno
const PAGE_ACCESS_TOKEN = process.env.PAGE_ACCESS_TOKEN;

// Adds support for GET requests to our webhook verificaion
app.get('/webhook', (req, res) => {

   // Your verify token. Should be a random string.
   let VERIFY_TOKEN = "1014238588"

   // Parse the query params
   // endpoint?hub.mode=subscribe&hub.verify_token=1014238588&hub.challenge=nose
   let mode = req.query['hub.mode'];
   let token = req.query['hub.verify_token'];
   let challenge = req.query['hub.challenge'];

   // Checks if a token and mode is in the query string of the request
   if (mode && token) {

     // Checks the mode and token sent is correct
     if (mode === 'subscribe' && token === VERIFY_TOKEN) {

       // Responds with the challenge token from the request
       console.log('WEBHOOK_VERIFIED');
       res.status(200).send(challenge);

     } else {
       // Responds with '403 Forbidden' if verify tokens do not match
       res.sendStatus(403);      
     }
   }
 });


 // Creates the endpoint for our webhook recive mensajes
app.post('/webhook', (req, res) => {  

   let body = req.body;

   // Checks this is an event from a page subscription
   if (body.object === 'page') {

     // Iterates over each entry - there may be multiple if batched
     body.entry.forEach(function(entry) {

       // Gets the message. entry.messaging is an array, but 
       // will only ever contain one message, so we get index 0
       // req.body.entry
       let webhook_event = entry.messaging[0];
       console.log(webhook_event);
     });

     // Returns a '200 OK' response to all requests
     res.status(200).send('EVENT_RECEIVED');
   } else {
     // Returns a '404 Not Found' if event is not from a page subscription
     res.sendStatus(404);
   }
});

// creates express http server
// Sets server port and logs message on success
app.listen(process.env.PORT || 1337, () => console.log('webhook is listening'));