Facebook messenger聊天机器人响应问题

Question

Currently I am developing a simple facebook messenger chatbot. I am using localhost url to tunnel via ngrok. I have also created a facebook app and a page on which bot should run. I also created a webhook for it. Everything was done successfully without any issue. But the problem is I can not get the reply from bot to work. I am receiving user's message but I can not get the bot to reply. So the user is not getting anything as a reply. Although in ngrok web interface I can see that the string which I want the bot to reply is there, but somehow it doesn't get send to the user as a reply. Here is the code for it. Can anyone point out the mistake? here is the ngrok inspect

Here is the code of my php file that is being called.

<?php
 if (isset($_GET['hub_verify_token'])) {
if ($_GET['hub_verify_token'] === 'verify_token') {
    echo $_GET['hub_challenge'];
    return;
} else {
    echo 'Invalid Verify Token';
    return;
}}$input = json_decode(file_get_contents('php://input'), true);if (isset($input['entry'][0]['messaging'][0]['sender']['id'])) {

$sender = $input['entry'][0]['messaging'][0]['sender']['id'];
$message = $input['entry'][0]['messaging'][0]['message']['text'];

$jsonData = [
    'recipient' => [ 'id' => $sender],
    'message' => [ 'text' => $message]
];

$url = "https://graph.facebook.com/v2.8/me/messages?access_token=EAAQlAQ9iGz8BABZATCZAN0hd5eyJ2mCFZBR9rDuZARkEmeqh8obC0yZBpiGxFuNbAyi6HHFI2lZCCiILeFNFDuiy2Sb9OHpLfDSIBhCsv7FgglOrzZAqy9yDFlUTZCEHfRfXBYjZCQOj42Vhl4muvyGIqqqsGDP1a0FYcGo9on3QlzgKp5JL8XbZBx";
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($jsonData));
curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
curl_exec($ch);
curl_close($ch);}?>

Answer 1

I finally get it to work. Here is the code for it.

<?php if (isset($_GET['hub_verify_token'])) {
if ($_GET['hub_verify_token'] === 'new_verify_token') {
    echo $_GET['hub_challenge'];
    return;
} else {
    echo 'Invalid Verify Token';
    return;
}}$input = json_decode(file_get_contents('php://input'), true);if(isset($input['entry'][0]['messaging'][0]['sender']['id'])){

$sender = $input['entry'][0]['messaging'][0]['sender']['id'];
$message = $input['entry'][0]['messaging'][0]['message']['text'];

$jsonData = [
    'recipient' => [ 'id' => $sender],
    'message' => [ 'text' => $message]
];

$url = "https://graph.facebook.com/v2.8/me/messages?access_token=EAAQlAQ9iGz8BAI5woul1IjMJFVcLW21ZBoZBbeBNaF80wvaPzdZBuDfEJ8NK7PPozUiVNfEjfhZAoWRJAqYHc7yiTA4J1wFOHZCs6DJYcMoPtEBuz6Icw22gNZCSjunjBcUMssXXnkmPEde4J5nU2AarXTUVxsujYPRS7ew97tCiYPDUY4tJSh";
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded'));
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($jsonData));
curl_exec($ch);
curl_close($ch);}?>