Laravel Validation

Laravel provides several different approaches to validate your application’s incoming data. By default, Laravel’s base controller class uses a ValidatesRequests trait which provides a convenient method to validate incoming HTTP request with a variety of powerful validation rules.

Validation Quickstart
To learn about Laravel’s powerful validation features, let’s look at a complete example of validating a form and displaying the error messages back to the user.

Defining The Routes
First, let’s assume we have the following routes defined in our routes/web.php file:

Route::get('post/create', 'PostController@create');
Route::post('post', 'PostController@store');

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Http\Controllers\Controller;

class PostController extends Controller
{
    /**
     * Show the form to create a new blog post.
     *
     * @return Response
     */
    public function create()
    {
        return view('post.create');
    }

    /**
     * Store a new blog post.
     *
     * @param  Request  $request
     * @return Response
     */
    public function store(Request $request)
    {
        // Validate and store the blog post...
    }
}

validation logic
基本コントローラーで作るのね。

public function store(Request $request)
{
    $validatedData = $request->validate([
        'title' => 'required|unique:posts|max:255',
        'body' => 'required',
    ]);

    // The blog post is valid...
}

$request->validate([
    'title' => 'required|unique:posts|max:255',
    'author.name' => 'required',
    'author.description' => 'required',
]);

So, in our example, the user will be redirected to our controller’s create method when validation fails, allowing us to display the error messages in the view:

<!-- /resources/views/post/create.blade.php -->

<h1>Create Post</h1>

@if ($errors->any())
    <div class="alert alert-danger">
        <ul>
            @foreach ($errors->all() as $error)
                <li>{{ $error }}</li>
            @endforeach
        </ul>
    </div>
@endif

<!-- Create Post Form -->

A Note On Optional Fields
By default, Laravel includes the TrimStrings and ConvertEmptyStringsToNull middleware in your application’s global middleware stack. These middleware are listed in the stack by the App\Http\Kernel class. Because of this, you will often need to mark your “optional” request fields as nullable if you do not want the validator to consider null values as invalid. For example:

$request->validate([
    'title' => 'required|unique:posts|max:255',
    'body' => 'required',
    'publish_at' => 'nullable|date',
]);

知識をupdateしないとあかんね。

AJAX Requests & Validation
In this example, we used a traditional form to send data to the application. However, many applications use AJAX requests. When using the validate method during an AJAX request, Laravel will not generate a redirect response. Instead, Laravel generates a JSON response containing all of the validation errors. This JSON response will be sent with a 422 HTTP status code.
ajaxの場合、対応が異なる様。