backend-php/controllers/CommodityCreateController.php

<?php

namespace Controllers;

use Libs\ResponseLib;
use Models\CommodityModel;
use Psr\Http\Message\ServerRequestInterface;

class CommodityCreateController
{
    public function __invoke(ServerRequestInterface $request)
    {
        $body = json_decode((string)$request->getBody(), true) ?? [];
        $name = trim((string)($body['name'] ?? ''));
        $flag = (string)($body['flag'] ?? 'a');

        if ($name === '') {
            return ResponseLib::sendFail('Validation failed: name is required', [], 'E_VALIDATE')->withStatus(400);
        }

        $model = new CommodityModel();
        $created = $model->create($name, $flag);

        return ResponseLib::sendOk($created, 'S_CREATED');
    }
}