connectivity.php

<?php
// Prevent the access to the script from the outside world
require_once dirname(__FILE__).'/../../include/init.inc';
if (empty($GLOBALS['SQ_SYSTEM']->user) || !($GLOBALS['SQ_SYSTEM']->user->canAccessBackend() || $GLOBALS['SQ_SYSTEM']->user->type() == 'simple_edit_user')) {
    exit;
}

$url = '';
if (isset($_REQUEST['connect_url'])) {
    $url = $_REQUEST['connect_url'];
}//end if

$current_url = '';
if (isset($_SERVER['HTTP_HOST']) && isset($_SERVER['PHP_SELF'])) {
    $current_url = $_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF'];
}//end if

// no url supplied or trying to recurse? return 0.
if (empty($url) || (!empty($current_url) && strpos($url, $current_url) !== FALSE)) {
    echo 0;
    exit;
}

$url_ok = @parse_url($url);
if (!$url_ok) {
    echo 0;
    exit;
}

$options = array(
        'FOLLOWLOCATION' => true,
        'NOBODY'         => true,
        'RETURNTRANSFER' => true,
        'CONNECTTIMEOUT' => 5,
        'MAXREDIRS'      => 5,
        'TIMEOUT'        => 5,
        );

$response = fetch_url($url, $options, array(), FALSE);
if ($response['errornumber'] === 0 && $response['curlinfo']['http_code'] == 200) {
    echo 1;
} else {
    echo 0;
}