如何为多个应用程序创建单个facebook webhook？

Question

我创建了一个webhook，用于FB Checkbook Send to Messenger App。我已经创建了一个FB应用程序，其中添加了FB登录和FB Messenger产品。

我很难研究代码在哪里为多个应用创建一个webhook。

这是webhook代码。

        This is the code. I need one webhook for many apps. Can someone help?

<?php
    $challenge = $_REQUEST['hub_challenge'];
    $verify_token = $_REQUEST['hub_verify_token'];

    if ($verify_token === 'abc123abc') {
      echo $challenge;
    }

    //$input = json_decode(file_get_contents('php://input'), true);
    //error_log(print_r($input, true));
    //error_log(print_r("shoaib", true));

    $pageId             = PAGE ID;
    $access_token       = "ACCESS TOKEN";
    /******************************************************
        To Receive Messages
    *******************************************************/
    $input      = json_decode(file_get_contents('php://input'), true);
    error_log(print_r($input, true));

    $sender     = $input['entry'][0]['messaging'][0]['sender']['id'];
    $message    = (isset($input['entry'][0]['messaging'][0]['message']['text'])) ? $input['entry'][0]['messaging'][0]['message']['text'] : '';
    $postback   = (isset($input['entry'][0]['messaging'][0]['postback']['payload'])) ? $input['entry'][0]['messaging'][0]['postback']['payload'] : '';
    $message_to_reply   = '';

    //error_log(print_r($input, true));
    ?>