86 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
			
		
		
	
	
			86 lines
		
	
	
		
			2.5 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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 * EsiResponseCacheStrategy knows how to compute the Response cache HTTP header
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 * based on the different ESI 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 ESI 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 EsiResponseCacheStrategy implements EsiResponseCacheStrategyInterface
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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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    /**
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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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            $this->ttls[] = $response->getTtl();
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            $this->maxAges[] = $response->getMaxAge();
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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 (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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