protected function parseFilename(HTTPRequest $request)
    {
        $filename = '';
        $next = $request->param('Filename');
        while ($next) {
            $filename = $filename ? File::join_paths($filename, $next) : $next;
            $next = $request->shift();
        }
        if ($extension = $request->getExtension()) {
            $filename = $filename . "." . $extension;
        }
        return $filename;
    }