public function verifAuthentificationExists()
 {
     session_start();
     if ($_SESSION[$this->session_name]) {
         $this->setEnableContent(true);
         return true;
     }
     if ($_POST['user'] && $_POST['pwd']) {
         $model = new Model();
         $name = $model->credentials();
         if ($name && !$_SESSION[$this->session_name]) {
             $this->createSession();
         } else {
             $this->throwAuthentificationForm();
         }
     } else {
         $this->throwAuthentificationForm();
     }
 }