App\Http\Controllers\EditorController::fileDownload PHP Method

    public function fileDownload(EditorHandler $handler, Storage $storage, $instanceId, $id)
    {
        if (empty($id) || !($file = File::find($id))) {
            throw new InvalidArgumentException();
        }
        if (Gate::denies('download', new Instance($handler->getPermKey($instanceId)))) {
            throw new AccessDeniedHttpException();
        }
        $storage->download($file);
    }