simple-slim-controller.php

<?php
namespace App\Controller;

use Slim\Http\Request;
use Slim\Http\Response;

class Home
{
    /**
     * @param Request $request
     * @param Response $response
     * @return Response
     */
    public function hello(Request $request, Response $response)
    {
        $string = $request->getParam('string');
        return $response->withJson(['result' => "Hello {$string}"], 200);
    }
}