function __construct($url)
 {
     if (!function_exists('curl_exec')) {
         die('Vtiger_HTTP_Client: Curl extension not enabled!');
     }
     parent::__construct();
     $this->_serviceurl = $url;
     $useragent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)";
     $this->set_user_agent($useragent);
     // Escape SSL certificate hostname verification
     curl_setopt($this->ch, CURLOPT_SSL_VERIFYHOST, 0);
 }