LocaleListener.php

<?php


/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Symfony\Component\HttpKernel\EventListener;

use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\RequestStack;
use Symfony\Component\HttpKernel\Event\FinishRequestEvent;
use Symfony\Component\HttpKernel\Event\KernelEvent;
use Symfony\Component\HttpKernel\Event\RequestEvent;
use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\Routing\RequestContextAwareInterface;

/**
 * Initializes the locale based on the current request.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 *
 * @final
 */
class LocaleListener implements EventSubscriberInterface {
    public function __construct(RequestStack $requestStack, string $defaultLocale = 'en', ?RequestContextAwareInterface $router = null, bool $useAcceptLanguageHeader = false, array $enabledLocales = []) {
    }
    public function setDefaultLocale(KernelEvent $event) : void {
        $event->getRequest()
            ->setDefaultLocale($this->defaultLocale);
    }
    public function onKernelRequest(RequestEvent $event) : void {
        $request = $event->getRequest();
        $this->setLocale($request);
        $this->setRouterContext($request);
    }
    public function onKernelFinishRequest(FinishRequestEvent $event) : void {
        if (null !== ($parentRequest = $this->requestStack
            ->getParentRequest())) {
            $this->setRouterContext($parentRequest);
        }
    }
    private function setLocale(Request $request) : void {
        if ($locale = $request->attributes
            ->get('_locale')) {
            $request->setLocale($locale);
        }
        elseif ($this->useAcceptLanguageHeader) {
            if ($request->getLanguages() && ($preferredLanguage = $request->getPreferredLanguage($this->enabledLocales))) {
                $request->setLocale($preferredLanguage);
            }
            $request->attributes
                ->set('_vary_by_language', true);
        }
    }
    private function setRouterContext(Request $request) : void {
        $this->router?->getContext()
            ->setParameter('_locale', $request->getLocale());
    }
    public static function getSubscribedEvents() : array {
        return [
            KernelEvents::REQUEST => [
                [
                    'setDefaultLocale',
                    100,
                ],
                // must be registered after the Router to have access to the _locale
[
                    'onKernelRequest',
                    16,
                ],
            ],
            KernelEvents::FINISH_REQUEST => [
                [
                    'onKernelFinishRequest',
                    0,
                ],
            ],
        ];
    }

}