stripping cookies for caching when using the Symfony2 HttpCache

gistfile1.php

<?php

require_once __DIR__.'/AppKernel.php';

use Symfony\Bundle\FrameworkBundle\HttpCache\HttpCache;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;

class AppCache extends HttpCache
{
    private $cookieWhitelist = array(
        'MYCOOKIE'
    );

    protected function lookup(Request $request, $catch = false)
    {
        $this->removeUnusedCookies($request);
        return parent::lookup($request, $catch);
    }

    protected function store(Request $request, Response $response)
    {
        $this->removeUnusedCookies($request, $response);
        parent::store($request, $response);
    }

    private function removeUnusedCookies(Request $request, Response $response = null)
    {
        $cookie = $request->headers->get('cookie');
        if (empty($cookie)) {
            return;
        }

        preg_match_all('/(?P<names>[^=]+)=(?P<values>[^\;]+)(;\s)?/im', $cookie, $cookieParts);
        $cookie = array();
        foreach ($cookieParts['names'] as $key => $value) {
            if (in_array($value, $this->cookieWhitelist)) {
                $cookie[] = $value.'='.$cookieParts['values'][$key];
            }
        }

        if (empty($cookie)) {
            $request->headers->remove('cookie');
        } else {
            $request->headers->set('cookie', implode(';', $cookie));
        }

        if ($response instanceof Response) {
            foreach ($response->headers->getCookies() as $cookie) {
                $name = $cookie->getName();
                if (!in_array($name, $this->cookieWhitelist)) {
                    $response->headers->removeCookie($name);
                }
            }
        }
    }
}