/**
  * Méthode qui retourne l'adresse ip d'un visiteur
  *
  * @return	string		adresse ip d'un visiteur
  **/
 public static function getIp()
 {
     if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
         # check ip from share internet
         $ip = $_SERVER['HTTP_CLIENT_IP'];
     } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
         # to check ip is pass from proxy
         $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
     } else {
         $ip = $_SERVER['REMOTE_ADDR'];
     }
     return plxUtils::isValidIp($ip) ? $ip : '';
 }