Validating JSON input Laravel - json

Question

I am using laravel , and json input from the client. I would like to know if there is a way to create a form request that does json validation instead of url parameters. I found this class online :
<?php
namespace App\Http\Requests;
use Illuminate\Foundation\Http\FormRequest;
abstract class JsonRequest extends FormRequest {
/**
* Get the validator instance for the request.
*
* #return \Illuminate\Validation\Validator
*/
protected function getValidatorInstance()
{
$factory = $this->container->make('Illuminate\Validation\Factory');
if (method_exists($this, 'validator'))
{
return $this->container->call([$this, 'validator'], compact('factory'));
}
return $factory->make(
$this->json()->all(), $this->container->call([$this, 'rules']), $this->messages(), $this->attributes()
);
}
}
Now , when I make a class that extends this instead of Request, I am able to validate. This is an example:
<?php
namespace App\Http\Requests;
use App\Http\Middleware\AuthTokenMiddleware;
use App\Http\Requests\Request;
use Illuminate\Support\Facades\Input;
class VotesCreateRequest extends JsonRequest
{
public function response(array $errors)
{
//
return response()->json(["error_list" => $errors], 200);
}
/**
* Determine if the user is authorized to make this request.
*
* #return bool
*/
public function authorize()
{return true;
if(AuthTokenMiddleware::getUser()->can('access-group',Input::get("grp_id"))){
return true;
}
else{
return false;
}
}
/**
* Get the validation rules that apply to the request.
*
* #return array
*/
public function rules()
{
return [
'sub_items'=>'required|array',
'sub_items.*.email' =>'required'
];
}
}
But I want to know how to validate items inside items of the json file .
For example, i have :
{"sub_items":["something","another thing","yet another","another ","last"]}
How do I validate if all these items in sub sub_items are of type email ?