Lumen can't set custom validation rules - laravel

Question

I try this code to set custom validation messages, but with no effect -
class TestController extends Controller
{
public function submit(Request $request)
{
$this->validate($request,
[
'items' => 'required'
],
[
'items.required' => 'test test'
]
);
}
}
But on error I got this response -
{
"error": "The given data failed to pass validation."
}
What wrong with this code?
UPD:
Earlier I edit App\Exceptions\Handler to put errors(in API response) in specific format -
{
"error": "123"
}
This code is reason that validation errors not shown -
public function render($request, Exception $e)
{
return response([
'error' => $e->getMessage()
], 500);
}
I update Handler::render method regarding to this purpose
public function render($request, Exception $e) {
$response = parent::render($request, $e);
if (isset($response->exception) and !empty($response->exception)) {
return response(['error' => $response->exception->getMessage()], 500);
} else {
return parent::render($request, $e);
}
}
But I think I need to improve this code.

Answer 1

It seems you mixed validation rules and messages.
The validate method takes 3 parameter: request, rules, messages.
Please try this:
public function submit(Request $request)
{
$rules = [
'items' => 'required',
'otheritems' => 'required',
];
$messages = [
'items.required' => 'Error: Please enter something.',
'otheritems.required' => 'Otheritems are also required',
];
$this->validate($request, $rules, $messages);
}
The latest Lumen version always gives back JSON, see documentation:
The $this->validate helper will always return JSON responses with the relevant error messages when validation fails. If you are not building a stateless API that solely sends JSON responses, you should use the full Laravel framework.
Update regarding error:
The given result by Lumen looks like that.
{"items":["Items are required"],"otheritems":["Otheritems are also required"]}
Each item that failed the validation gets an entry in your response. So your error bag, need to be a JSON array.
Custom exception render method:
public function render($request, Exception $e)
{
$response = parent::render($request, $e);
if ($response->getStatusCode() == 422) {
$renderResult = parent::render($request, $e);
$returnResult['error'] = json_decode($renderResult->content(), true);
$returnResult = json_encode($returnResult);
return new Response($returnResult, $response->getStatusCode());
} else {
return parent::render($request, $e);
}
}