Change locale in Zend Expressive by query params and middleware

SetLocalMiddleware.php

<?php
namespace CodeEmailMKT\Application\Middleware;

use Locale;
use Psr\Http\Message\ServerRequestInterface;
use Zend\Expressive\Helper\UrlHelper;

class SetLocaleMiddleware
{
    private $helper;

    public function __construct(UrlHelper $helper)
    {
        $this->helper = $helper;
    }

    public function __invoke(ServerRequestInterface $request, $response, callable $next)
    {
        $queryParams = $request->getQueryParams();

        $locale = $queryParams['locale'] ?? '';
        if (!preg_match('/(?P<locale>[a-z]{2,3}([-_][a-zA-Z]{2}|))/', $locale, $matches)) {
            Locale::setDefault('de_DE');
            return $next($request, $response);
        }

        $locale = $matches['locale'];
        Locale::setDefault(Locale::canonicalize($locale));
        $this->helper->setBasePath($locale);

        return $next(
            $request,
            $response
        );
    }
}