Symfony2 wrong locale detection?

Question

Following Symfony2 guide about translation i found that inferred locale from http headers (stored in $this->get(\'session\')->getLocale()) is wrong (sent

Answer 1

per HTTP-Standard you should be using a different URL for each translated version of the page. What remains is a simple action that will infer the best-to-use locale from the request and redirect to the corresponding page:

/**
 * @Route("/")
 */
public function localeRedirectAction() {
    /* @var $request \Symfony\Component\HttpFoundation\Request */
    /* @var $session \Symfony\Component\HttpFoundation\Session */
    $req = $this->getRequest();
    $session = $this->get('session');

    $session->setLocale($req->getPreferredLanguage(array('de', 'en')));

    return $this->redirect($this->generateUrl('home'));
}

if you need to do this for any page, you'll basically need to do the same, but within a Listener for the kernel.request-Event. In order to be reliably called after the route-matcher did it's work you should set the priority of the listener to a value < 0:

# services.yml
services:
  my_locale_listener:
    class: Namespace\LocaleListener
    tags: [{ name: kernel.event_listener, event: kernel.request, method: onKernelRequest, priority: -255 }]
    arguments: [ @service_container, [ 'en', 'fr', 'de', 'es', 'it' ] ]

the listener would then look like this:

class LocaleListener {
    public function __construct($container, $availableLocales) {
        $this->container = $container;
        $this->availableLocales = $availableLocales;
    }

    public function onKernelRequest(GetResponseEvent $e) {
        $req = $e->getRequest();
        $locale = $req->getPreferredLanguage($this->availableLocales);

        // generate a new URL from the current route-name and -params, overwriting
        // the current locale
        $routeName = $req->attributes->get('_route');
        $routeParams = array_merge($req->attributes->all(), array('_locale' => $locale));
        $localizedUrl = $this->container->get('router')->generateUrl($routeName, $routeParams);

        $e->setResponse(new RedirectResponse($localizedUrl));
    }
}

P.S. i'm not entirely confident that this code actually works, but it should give a basic idea on how this could be done.