PHP Telegram Webhook

telegram_webhook.php

<?php
  if(!preg_match('/^149\.154\.167\.(19[7-9]|20[0-9]|21[0-9]|22[0-9]|23[0-3])$/', $_SERVER['REMOTE_ADDR'])) {
    die('IP Address not allowed.');
  }

  if($_SERVER['REQUEST_METHOD'] != 'POST') {
    die('Request method not allowed.');
  }

  $token = '<bot token here>';
  $rcv = file_get_contents('php://input');
  $m = json_decode($rcv, true);
  
  print_r($m);

  if(isset($m['message']['text'])) {
    $chatid = $m['message']['chat']['id'];
    $firstname = $m['message']['chat']['first_name'];
    sendmsg($m, 'Hi '.$firstname.'!');
  }

  function sendmsg($m, $msg) {
    global $token;
    $chatid = $m['message']['chat']['id'];
    $firstname = $m['message']['chat']['first_name'];
    unset($a); exec('curl -s -d "chat_id='.$chatid.'&text='.urlencode($msg).'" "https://api.telegram.org/bot'.$token.'/sendMessage"', $a);
  }
?>