composer require urameshibr/lumen-form-request:1.4

composer require urameshibr/lumen-form-request

$app->register(Urameshibr\Providers\FormRequestServiceProvider::class);

<?php

namespace App\Http\Requests;

use Urameshibr\Requests\FormRequest;

class StoreDeviceRequest extends FormRequest
{
	public function authorize()
	{
		return true;
	}

	public function rules()
	{
		return [
			'mac_address' => 'required|unique:devices,mac_address'
		];
	}
}