REST API post field validation Laravel 5.1 - php

Question

I need to check if I have all posted variables are required or else throw error.
Till Now I am doing like this
Routes.php
Route::post('/api/ws_fetchuser', 'UserController#fetch_user_details');
UserController.php
<?php
namespace App\Http\Controllers;
use App\Http\Requests;
use Illuminate\Http\Request;
use App\User;
class UserController extends Controller
{
public function fetch_user_details(Request $request)
{
if(!empty($request) && $request->id!='')
{
print_r($request->id);
}
else
{
return response(array(
'error' => false,
'message' =>'please enter all form fields',
),200);
}
}
}
I am checking like this $request->id!='', is there any validation rules or methods which I can use to check id is required field.
I have added this validation in my controller as well but what if id is not present how can I show the error?
Updated Validation Code:
public function fetch_user_details(Request $request)
{
$this->validate($request, [
'id' => 'required'
]);
print_r($request->id);
}

Answer 1

$this->validate() methods designed to redirect back when validation failed, So instead of that you can create a validator instance and get the error list manually.
use Validator;
$validator = Validator::make($request->all(), [
'id' => 'required'
]);
if ($validator->fails()) {
return json_encode($validator->errors()->all());
}