public function getAssetFile($file) {
        if (is_file($file)) {
            return new AssetFile($file);
        }
        $ext = pathinfo($file, PATHINFO_EXTENSION);
        if (strpos($file, '@') === 0 && ($ext == 'js' || $ext == 'css')) {
            $file = $ext.'/'. substr($file, 1);
        }
        return new AssetFile(Factory::public_path()->file($this->assetsDirectory.$file));
    }