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