protected function configureOutputLimit()
    {
        if ($this->request->input('only')) {
            $only = explode(',', $this->request->input('only'));

            $validator = app('validator')->make(
                ['only' => $only],
                ['only' => 'array|in:data,meta']
            );

            if ($validator->failed()) {
                $this->respondWithError("Invalid value for `only`.");
            } else {
                $this->only = array_flip(array_diff(['data', 'meta'], $only));
            }
        }
    }