PHP で Slim を使ったルーティング

composer create-project slim/slim-skeleton test_slim 

cd test_slim
php -S localhost:8885 -t public

composer start
> php -S localhost:8080 -t public

....
"scripts": {
    "start": "php -S localhost:8885 -t public",
    "test": "phpunit"
}

...
return function (App $app) {
    $app->options('/{routes:.*}', function (Request $request, Response $response) {
        // CORS Pre-Flight OPTIONS Request Handler
        return $response;
    });

    $app->get('/', function (Request $request, Response $response) {
        $response->getBody()->write('Hello world!');
        return $response;
    });

    $app->group('/users', function (Group $group) {
        $group->get('', ListUsersAction::class);
        $group->get('/{id}', ViewUserAction::class);
    });
};

{
    "statusCode": 200,
    "data": [
        {
            "id": 1,
            "username": "bill.gates",
            "firstName": "Bill",
            "lastName": "Gates"
        },
...
        {
            "id": 5,
            "username": "jack.dorsey",
            "firstName": "Jack",
            "lastName": "Dorsey"
        }
    ]
}

{
    "statusCode": 200,
    "data": {
        "id": 5,
        "username": "jack.dorsey",
        "firstName": "Jack",
        "lastName": "Dorsey"
    }
}

$app->group('/users', function (Group $group) {
    $group->get('', ListUsersAction::class);
    $group->get('/{id}', ViewUserAction::class);
});

...
class ViewUserAction extends UserAction
{
    /**
     * {@inheritdoc}
     */
    protected function action(): Response
    {
        $userId = (int) $this->resolveArg('id');
        $user = $this->userRepository->findUserOfId($userId);

        $this->logger->info("User of id `${userId}` was viewed.");

        return $this->respondWithData($user);
    }
}

$app->group('/users', function (Group $group) {
    $group->get('', ListUsersAction::class);
    $group->get('/{id}', ViewUserAction::class);
    $group->post('', CreateUserAction::class); // ←追記
});

<?php

declare(strict_types=1);

namespace App\Application\Actions\User;

use Psr\Http\Message\ResponseInterface as Response;
use App\Domain\User\User;

class CreateUserAction extends UserAction
{
    /**
     * {@inheritdoc}
     */
    protected function action(): Response
    {
        // リクエストオブジェクトからパースされたボディデータを取得
        $data = $this->request->getParsedBody();

        // ユーザーデータを元にUserオブジェクトを作成
        $user = new User(
            null,
            $data['username'],
            $data['firstname'],
            $data['lastname']
        );

        $newUser = $this->userRepository->create($user);

        $this->logger->info("Created new user.");

        return $this->respondWithData($newUser);
    }
}

...
public function create(User $user): User;

public function create(User $user): User
{
    $newId = max(array_keys($this->users)) + 1;
    $user->setId($newId);
    $this->users[$newId] = $user;
    return $user;
}

$ curl -X POST http://localhost:8885/users -H "Content-Type: application/json" -d '{"username":"Toshihiko Arai", "firstname":"Toshihiko", "lastname":"Arai"}'

{
    "statusCode": 200,
    "data": {
        "id": 6,
        "username": "toshihiko arai",
        "firstName": "Toshihiko",
        "lastName": "Arai"
    }
}