make controller

src/Controller/DiffDaysController.php

+<?php
+
+namespace App\Controller;
+
+use DateTimeImmutable;
+use HttpResponse;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Attribute\Route;
+
+class DiffDaysController extends AbstractController
+{
+    /**
+     * Контроллер вернет кол-во дней между датами
+     * @param Request $request
+     * @return Response
+     */
+    #[Route('/diff/days', name: 'app_diff_days', methods: ['POST'])]
+    public function index(Request $request): Response
+    {
+        $dateStart = new DateTimeImmutable($request->toArray()['date_start']);
+        $dateEnd = new DateTimeImmutable($request->toArray()['date_end']);
+
+        return new JsonResponse(["interval"=>($dateStart->diff($dateEnd)->format("%a"))]
+            , Response::HTTP_OK);
+    }
+}