Fragment path resolver to clear cache for widgets rendered by render_esi

FragmentPathResolver.php

<?php

namespace AppBundle\Cache;

use Symfony\Component\HttpFoundation\RequestStack;
use Symfony\Component\HttpKernel\Controller\ControllerReference;
use Symfony\Component\HttpKernel\Fragment\FragmentRendererInterface;

class FragmentPathResolver
{
    /**
     * @var FragmentRendererInterface
     */
    private $fragmentRenderer;

    /**
     * @var RequestStack
     */
    private $requestStack;

    public function __construct(FragmentRendererInterface $fragmentRenderer, RequestStack $requestStack)
    {
        $this->fragmentRenderer = $fragmentRenderer;
        $this->requestStack = $requestStack;
    }

    /**
     * @param string $controller
     * @param array $parameters
     * @param array $query
     * @return null|string
     */
    public function resolve($controller, array $parameters = array(), array $query = array())
    {
        $controllerReference = new ControllerReference($controller, $parameters, $query);
        $response = $this->fragmentRenderer->render($controllerReference, $this->requestStack->getMasterRequest());

        return $this->parsePath($response->getContent());
    }

    /**
     * @param string $content
     * @return null|string
     */
    private function parsePath($content)
    {
        if (empty($content)) {
            return null;
        }

        if (!preg_match('/src=[\'"](.*?)[\'"]/iu', $content, $matches)) {
            return null;
        }

        return $this->fixOrder($matches[1]);
    }

    /**
     * @param $uri
     * @return string
     */
    private function fixOrder($uri)
    {
        $hashPosition = strpos($uri, '&_hash=');
        if ($hashPosition === false) {
            return null;
        }
        $hash = substr($uri, $hashPosition + 1);
        $uri = substr($uri, 0, $hashPosition);

        $queryPosition = strpos($uri, '?');
        if ($queryPosition === false) {
            return null;
        }

        $fragment = substr($uri, 0, $queryPosition + 1);
        $query = substr($uri, $queryPosition + 1);

        return sprintf('%s%s&%s', $fragment, $hash, $query);
    }
}