/**
  * Set proxy information
  *
  * @param string $host Proxy hostname and port (localhost:1234)
  * @param string $user Proxy username
  * @param string $pass Proxy password
  * @param constant $type CURL proxy type
  * @return void
  */
 public static function setProxy($host, $user = null, $pass = null, $type = CURLPROXY_SOCKS5)
 {
     self::$proxy = array('host' => $host, 'type' => $type, 'user' => null, 'pass' => 'null');
 }