Redirect to page according to the Accept-Language header using Symfony 5

HomepageController.php

<?php

namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Annotation\Route;

class HomepageController extends AbstractController
{
    /**
     * @Route("/", name="homepage")
     */
    public function index(Request $request)
    {
        return $this->redirect($this->generateUrl('menu', [
            '_locale' => $request->getLocale()
        ]));
    }
}

HomepageControllerTest.php

<?php

namespace App\Tests\Controller;

use App\Controller\HomepageController;
use PHPUnit\Framework\TestCase;
use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;

class HomepageControllerTest extends WebTestCase
{
    /**
     * @test
     * @dataProvider localesProvider
     */
    public function itShouldRedirectFromAcceptLanguageHeader(string $locale, $expectedUri)
    {
        $client = static::createClient();
        $client->request(
            'GET',
            '/',
            [],
            [],
            [
            'HTTP_ACCEPT_LANGUAGE' => $locale
        ]
        );
        
        $location = $client->getResponse()->headers->get('Location');
        if ($locale !== '') {
            $this->assertEquals($expectedUri, $location);
        } else {
            $expectedUri = '/en/ementa';
            $this->assertEquals($expectedUri, $location);
        }
    }
    
    public function localesProvider(): array
    {
        return [
            'english' => [
                'en',
                '/en/ementa'
            ],
            'english en-US' => [
                'en-US',
                '/en/ementa'
            ],
            'french' => [
                'fr',
                '/fr/ementa'
            ],
            'german' => [
                'de',
                '/de/ementa'
            ],
            'portuguese' => [
                'pt',
                '/pt/ementa',
            ],
            'portuguese brazillian' => [
                'pt-BR',
                '/pt/ementa'
            ],
            'spanish' => [
                'es',
                '/es/ementa'
            ],
            'empty header should give default language english' => [
                '',
                '/en/ementa'
            ]
        ];
    }
}

LanguageListenerSubscriber.php

<?php

namespace App\EventSubscriber;

use Negotiation\AcceptLanguage;
use Negotiation\LanguageNegotiator;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\AcceptHeader;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpKernel\Event\RequestEvent;
use Symfony\Component\Routing\RouterInterface;

class LanguageListenerSubscriber implements EventSubscriberInterface
{
    private array $locales;
    private const DEFAULT_LOCALE = 'en';
    /**
     * @var RouterInterface
     */
    private RouterInterface $router;
    private array $priorities;

    public function __construct(array $locales, array $priorities, RouterInterface $router)
    {
        $this->locales = $locales;
        $this->priorities = $priorities;
        $this->router = $router;
    }

    public function onKernelRequest(RequestEvent $event)
    {
        $request = $event->getRequest();
        // ignore request because of language switcher
        if ($request->getRequestUri() === $this->router->generate('menu')) {
            return;
        }
        
        $request->setLocale(self::DEFAULT_LOCALE);
        $acceptLanguageHeader = $request->headers->get('Accept-Language');
        if (empty($acceptLanguageHeader)) {
            return;
        }
        
        $priorities = $this->priorities;
        $bestLanguage = (new LanguageNegotiator())->getBest(
            $acceptLanguageHeader,
            $priorities
        );
        
        if ($bestLanguage !== null) {
            $bestLanguageLocale = $bestLanguage->getValue();
            $bestLanguageLocaleFirst = explode('-', $bestLanguageLocale)[0] ?? '';
            if ($this->languageSupported($this->locales, $bestLanguageLocaleFirst)) {
                $request->setLocale($bestLanguageLocaleFirst);
            }
        }
    }
    
    private function languageSupported(array $locales, string $selectedLocale): bool
    {
        foreach ($locales as $locale) {
            if ($locale['locale'] === $selectedLocale) {
                return true;
            }
        }
        
        return false;
    }

    public static function getSubscribedEvents()
    {
        return [
            'kernel.request' => 'onKernelRequest',
        ];
    }
}

MenuController.php

<?php
namespace App\Controller;

use App\Repository\CategoryRepository;
use App\Repository\MealItemRepository;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;

class MenuController extends AbstractController
{   
    /**
     * @Route("/{_locale}/ementa", name="menu",
     *      locale="pt",
     *      requirements={
     *          "_locale": "pt|es|en|fr|it|de"
     *      }
     * )
     */
    public function indexWithLanguage(
        MealItemRepository $mealItemRepository,
        CategoryRepository $categoryRepository,
        Request $request
    ) {
        $languageSelected = $request->getLocale();
        $mealItemsByCategory = $this->getMealItemsByCategory($categoryRepository, $mealItemRepository, $languageSelected);

        return $this->render('menu/index.html.twig', [
            'mealItemsByCategory' => $mealItemsByCategory,
            'languageSelected' => $languageSelected
        ]);
    }
}