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- <?php
- /*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <fabien@symfony.com>
- *
- * This code is partially based on the Rack-Cache library by Ryan Tomayko,
- * which is released under the MIT license.
- * (based on commit 02d2b48d75bcb63cf1c0c7149c077ad256542801)
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
- namespace Symfony\Component\HttpKernel\HttpCache;
- use Symfony\Component\HttpFoundation\Response;
- /**
- * ResponseCacheStrategy knows how to compute the Response cache HTTP header
- * based on the different response cache headers.
- *
- * This implementation changes the master response TTL to the smallest TTL received
- * or force validation if one of the surrogates has validation cache strategy.
- *
- * @author Fabien Potencier <fabien@symfony.com>
- */
- class ResponseCacheStrategy implements ResponseCacheStrategyInterface
- {
- private $cacheable = true;
- private $embeddedResponses = 0;
- private $ttls = array();
- private $maxAges = array();
- private $isNotCacheableResponseEmbedded = false;
- /**
- * {@inheritdoc}
- */
- public function add(Response $response)
- {
- if ($response->isValidateable()) {
- $this->cacheable = false;
- } else {
- $maxAge = $response->getMaxAge();
- $this->ttls[] = $response->getTtl();
- $this->maxAges[] = $maxAge;
- if (null === $maxAge) {
- $this->isNotCacheableResponseEmbedded = true;
- }
- }
- ++$this->embeddedResponses;
- }
- /**
- * {@inheritdoc}
- */
- public function update(Response $response)
- {
- // if we have no embedded Response, do nothing
- if (0 === $this->embeddedResponses) {
- return;
- }
- // Remove validation related headers in order to avoid browsers using
- // their own cache, because some of the response content comes from
- // at least one embedded response (which likely has a different caching strategy).
- if ($response->isValidateable()) {
- $response->setEtag(null);
- $response->setLastModified(null);
- $this->cacheable = false;
- }
- if (!$this->cacheable) {
- $response->headers->set('Cache-Control', 'no-cache, must-revalidate');
- return;
- }
- $this->ttls[] = $response->getTtl();
- $this->maxAges[] = $response->getMaxAge();
- if ($this->isNotCacheableResponseEmbedded) {
- $response->headers->removeCacheControlDirective('s-maxage');
- } elseif (null !== $maxAge = min($this->maxAges)) {
- $response->setSharedMaxAge($maxAge);
- $response->headers->set('Age', $maxAge - min($this->ttls));
- }
- $response->setMaxAge(0);
- }
- }
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