private static function checkSession()
 {
     if (Session::exists('session_id') && Session::exists('token')) {
         return self::checkLogin(Session::getValue('session_id'), Session::getValue('token'));
     } else {
         return false;
     }
 }
 public function checkLoginCaptcha($params)
 {
     //Si esta autenticado redireccionar a la vista Principal del sitio y el captcha coincide con el generado
     if (Session::getValue('captcha') == $params['captcha']) {
         if (AuthenticationUtils::login($params['username'], $params['password'])) {
             header('Location: ' . URL_BASE . "/index.php/Index/index");
         }
         header('Location: ' . URL_BASE . "/index.php/Authentication/showLoginWithCaptcha");
     }
     header('Location: ' . URL_BASE . "/index.php/Authentication/showLoginWithCaptcha");
 }
 public function generateCaptcha($w = 350, $h = 60)
 {
     unlink(getcwd() . "/public/uploads/captcha.png");
     Session::setValue('captcha', self::texto());
     $captcha = \imagecreatetruecolor($w, $h);
     $colorFondo = \imagecolorallocate($captcha, 0, 0, 255);
     $colorTexto = \imagecolorallocate($captcha, 255, 255, 0);
     $colorLinea = \imagecolorallocate($captcha, 255, 105, 180);
     \imageline($captcha, 120, 39, 250, 39, $colorLinea);
     \imageline($captcha, 120, 45, 250, 45, $colorLinea);
     \imageline($captcha, 120, 50, 250, 50, $colorLinea);
     \imagestring($captcha, 5, 150, 35, Session::getValue('captcha'), $colorTexto);
     imagepng($captcha, getcwd() . "/public/uploads/captcha.png");
     imagedestroy($captcha);
 }