<?php // Extract URL from 'url' GET field $url = (string)filter_input(INPUT_GET, 'url'); if (empty($url)) { exit; } // Strip endpoint to scheme://host:port/vm-ping to prevent abuse $url = parse_url($url); if (!$url) { exit; } $url = $url['scheme'].'://'.$url['host'].(!empty($url['port']) ? ':'.$url['port'] : '').'/vm-ping'; // Ping the remote endpoint $ch = curl_init($url); curl_setopt_array($ch, [CURLOPT_RETURNTRANSFER => TRUE, CURLOPT_HEADER => FALSE, CURLOPT_SSL_VERIFYHOST => FALSE, CURLOPT_SSL_VERIFYPEER => FALSE, CURLOPT_TIMEOUT => 4]); $content = curl_exec($ch); curl_close($ch); if ($content == 'vm-pong') { echo 'vm-pong'; }