protected function getToken($src)
    {
        $full_path = \Yii::getAlias('@webroot') . "/$src";

        try {
            $token =  hash('crc32b', '$full_path ' . filemtime($full_path));
        } catch (\Exception $ex) {
            \Yii::error($ex);
            return null;
        } catch (\Throwable $ex) {
            \Yii::error($ex);
            return null;
        }

        return $token;
    }