protected function constructUploadReceiver()
    {
        // Set Upload instance
        $this->setUpload(Upload::create());

        // filter out '' since this would be a regex problem on JS end
        $this->getValidator()->setAllowedExtensions(
            array_filter(File::config()->allowed_extensions)
        );

        // get the lower max size
        $maxUpload = File::ini2bytes(ini_get('upload_max_filesize'));
        $maxPost = File::ini2bytes(ini_get('post_max_size'));
        $this->getValidator()->setAllowedMaxFileSize(min($maxUpload, $maxPost));
    }