718 lines
		
	
	
		
			26 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
			
		
		
	
	
			718 lines
		
	
	
		
			26 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
| <?php
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| 
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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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|  * 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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| 
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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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| 
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| namespace Symfony\Component\HttpKernel\HttpCache;
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| 
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| use Symfony\Component\HttpFoundation\Request;
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| use Symfony\Component\HttpFoundation\Response;
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| use Symfony\Component\HttpKernel\HttpKernelInterface;
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| use Symfony\Component\HttpKernel\TerminableInterface;
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| 
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| /**
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|  * Cache provides HTTP caching.
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|  *
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|  * @author Fabien Potencier <fabien@symfony.com>
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|  */
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| class HttpCache implements HttpKernelInterface, TerminableInterface
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| {
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|     private HttpKernelInterface $kernel;
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|     private StoreInterface $store;
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|     private Request $request;
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|     private ?SurrogateInterface $surrogate;
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|     private ?ResponseCacheStrategyInterface $surrogateCacheStrategy = null;
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|     private array $options = [];
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|     private array $traces = [];
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| 
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|     /**
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|      * Constructor.
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|      *
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|      * The available options are:
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|      *
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|      *   * debug                  If true, exceptions are thrown when things go wrong. Otherwise, the cache
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|      *                            will try to carry on and deliver a meaningful response.
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|      *
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|      *   * trace_level            May be one of 'none', 'short' and 'full'. For 'short', a concise trace of the
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|      *                            main request will be added as an HTTP header. 'full' will add traces for all
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|      *                            requests (including ESI subrequests). (default: 'full' if in debug; 'none' otherwise)
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|      *
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|      *   * trace_header           Header name to use for traces. (default: X-Symfony-Cache)
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|      *
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|      *   * default_ttl            The number of seconds that a cache entry should be considered
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|      *                            fresh when no explicit freshness information is provided in
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|      *                            a response. Explicit Cache-Control or Expires headers
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|      *                            override this value. (default: 0)
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|      *
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|      *   * private_headers        Set of request headers that trigger "private" cache-control behavior
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|      *                            on responses that don't explicitly state whether the response is
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|      *                            public or private via a Cache-Control directive. (default: Authorization and Cookie)
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|      *
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|      *   * allow_reload           Specifies whether the client can force a cache reload by including a
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|      *                            Cache-Control "no-cache" directive in the request. Set it to ``true``
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|      *                            for compliance with RFC 2616. (default: false)
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|      *
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|      *   * allow_revalidate       Specifies whether the client can force a cache revalidate by including
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|      *                            a Cache-Control "max-age=0" directive in the request. Set it to ``true``
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|      *                            for compliance with RFC 2616. (default: false)
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|      *
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|      *   * stale_while_revalidate Specifies the default number of seconds (the granularity is the second as the
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|      *                            Response TTL precision is a second) during which the cache can immediately return
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|      *                            a stale response while it revalidates it in the background (default: 2).
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|      *                            This setting is overridden by the stale-while-revalidate HTTP Cache-Control
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|      *                            extension (see RFC 5861).
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|      *
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|      *   * stale_if_error         Specifies the default number of seconds (the granularity is the second) during which
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|      *                            the cache can serve a stale response when an error is encountered (default: 60).
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|      *                            This setting is overridden by the stale-if-error HTTP Cache-Control extension
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|      *                            (see RFC 5861).
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|      *
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|      *   * terminate_on_cache_hit Specifies if the kernel.terminate event should be dispatched even when the cache
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|      *                            was hit (default: true).
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|      *                            Unless your application needs to process events on cache hits, it is recommended
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|      *                            to set this to false to avoid having to bootstrap the Symfony framework on a cache hit.
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|      */
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|     public function __construct(HttpKernelInterface $kernel, StoreInterface $store, SurrogateInterface $surrogate = null, array $options = [])
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|     {
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|         $this->store = $store;
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|         $this->kernel = $kernel;
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|         $this->surrogate = $surrogate;
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| 
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|         // needed in case there is a fatal error because the backend is too slow to respond
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|         register_shutdown_function($this->store->cleanup(...));
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| 
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|         $this->options = array_merge([
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|             'debug' => false,
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|             'default_ttl' => 0,
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|             'private_headers' => ['Authorization', 'Cookie'],
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|             'allow_reload' => false,
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|             'allow_revalidate' => false,
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|             'stale_while_revalidate' => 2,
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|             'stale_if_error' => 60,
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|             'trace_level' => 'none',
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|             'trace_header' => 'X-Symfony-Cache',
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|             'terminate_on_cache_hit' => true,
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|         ], $options);
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| 
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|         if (!isset($options['trace_level'])) {
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|             $this->options['trace_level'] = $this->options['debug'] ? 'full' : 'none';
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|         }
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|     }
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| 
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|     /**
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|      * Gets the current store.
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|      */
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|     public function getStore(): StoreInterface
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|     {
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|         return $this->store;
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|     }
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| 
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|     /**
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|      * Returns an array of events that took place during processing of the last request.
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|      */
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|     public function getTraces(): array
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|     {
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|         return $this->traces;
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|     }
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| 
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|     private function addTraces(Response $response)
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|     {
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|         $traceString = null;
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| 
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|         if ('full' === $this->options['trace_level']) {
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|             $traceString = $this->getLog();
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|         }
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| 
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|         if ('short' === $this->options['trace_level'] && $masterId = array_key_first($this->traces)) {
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|             $traceString = implode('/', $this->traces[$masterId]);
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|         }
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| 
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|         if (null !== $traceString) {
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|             $response->headers->add([$this->options['trace_header'] => $traceString]);
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|         }
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|     }
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| 
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|     /**
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|      * Returns a log message for the events of the last request processing.
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|      */
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|     public function getLog(): string
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|     {
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|         $log = [];
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|         foreach ($this->traces as $request => $traces) {
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|             $log[] = sprintf('%s: %s', $request, implode(', ', $traces));
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|         }
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| 
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|         return implode('; ', $log);
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|     }
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| 
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|     /**
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|      * Gets the Request instance associated with the main request.
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|      */
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|     public function getRequest(): Request
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|     {
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|         return $this->request;
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|     }
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| 
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|     /**
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|      * Gets the Kernel instance.
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|      */
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|     public function getKernel(): HttpKernelInterface
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|     {
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|         return $this->kernel;
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|     }
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| 
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|     /**
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|      * Gets the Surrogate instance.
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|      *
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|      * @throws \LogicException
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|      */
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|     public function getSurrogate(): SurrogateInterface
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|     {
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|         return $this->surrogate;
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|     }
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| 
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|     public function handle(Request $request, int $type = HttpKernelInterface::MAIN_REQUEST, bool $catch = true): Response
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|     {
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|         // FIXME: catch exceptions and implement a 500 error page here? -> in Varnish, there is a built-in error page mechanism
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|         if (HttpKernelInterface::MAIN_REQUEST === $type) {
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|             $this->traces = [];
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|             // Keep a clone of the original request for surrogates so they can access it.
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|             // We must clone here to get a separate instance because the application will modify the request during
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|             // the application flow (we know it always does because we do ourselves by setting REMOTE_ADDR to 127.0.0.1
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|             // and adding the X-Forwarded-For header, see HttpCache::forward()).
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|             $this->request = clone $request;
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|             if (null !== $this->surrogate) {
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|                 $this->surrogateCacheStrategy = $this->surrogate->createCacheStrategy();
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|             }
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|         }
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| 
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|         $this->traces[$this->getTraceKey($request)] = [];
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| 
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|         if (!$request->isMethodSafe()) {
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|             $response = $this->invalidate($request, $catch);
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|         } elseif ($request->headers->has('expect') || !$request->isMethodCacheable()) {
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|             $response = $this->pass($request, $catch);
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|         } elseif ($this->options['allow_reload'] && $request->isNoCache()) {
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|             /*
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|                 If allow_reload is configured and the client requests "Cache-Control: no-cache",
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|                 reload the cache by fetching a fresh response and caching it (if possible).
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|             */
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|             $this->record($request, 'reload');
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|             $response = $this->fetch($request, $catch);
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|         } else {
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|             $response = $this->lookup($request, $catch);
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|         }
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| 
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|         $this->restoreResponseBody($request, $response);
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| 
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|         if (HttpKernelInterface::MAIN_REQUEST === $type) {
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|             $this->addTraces($response);
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|         }
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| 
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|         if (null !== $this->surrogate) {
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|             if (HttpKernelInterface::MAIN_REQUEST === $type) {
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|                 $this->surrogateCacheStrategy->update($response);
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|             } else {
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|                 $this->surrogateCacheStrategy->add($response);
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|             }
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|         }
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| 
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|         $response->prepare($request);
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| 
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|         $response->isNotModified($request);
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| 
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|         return $response;
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|     }
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| 
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|     public function terminate(Request $request, Response $response)
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|     {
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|         // Do not call any listeners in case of a cache hit.
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|         // This ensures identical behavior as if you had a separate
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|         // reverse caching proxy such as Varnish and the like.
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|         if ($this->options['terminate_on_cache_hit']) {
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|             trigger_deprecation('symfony/http-kernel', '6.2', 'Setting "terminate_on_cache_hit" to "true" is deprecated and will be changed to "false" in Symfony 7.0.');
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|         } elseif (\in_array('fresh', $this->traces[$this->getTraceKey($request)] ?? [], true)) {
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|             return;
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|         }
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| 
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|         if ($this->getKernel() instanceof TerminableInterface) {
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|             $this->getKernel()->terminate($request, $response);
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|         }
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|     }
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| 
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|     /**
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|      * Forwards the Request to the backend without storing the Response in the cache.
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|      *
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|      * @param bool $catch Whether to process exceptions
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|      */
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|     protected function pass(Request $request, bool $catch = false): Response
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|     {
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|         $this->record($request, 'pass');
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| 
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|         return $this->forward($request, $catch);
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|     }
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| 
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|     /**
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|      * Invalidates non-safe methods (like POST, PUT, and DELETE).
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|      *
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|      * @param bool $catch Whether to process exceptions
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|      *
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|      * @throws \Exception
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|      *
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|      * @see RFC2616 13.10
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|      */
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|     protected function invalidate(Request $request, bool $catch = false): Response
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|     {
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|         $response = $this->pass($request, $catch);
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| 
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|         // invalidate only when the response is successful
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|         if ($response->isSuccessful() || $response->isRedirect()) {
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|             try {
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|                 $this->store->invalidate($request);
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| 
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|                 // As per the RFC, invalidate Location and Content-Location URLs if present
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|                 foreach (['Location', 'Content-Location'] as $header) {
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|                     if ($uri = $response->headers->get($header)) {
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|                         $subRequest = Request::create($uri, 'get', [], [], [], $request->server->all());
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| 
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|                         $this->store->invalidate($subRequest);
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|                     }
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|                 }
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| 
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|                 $this->record($request, 'invalidate');
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|             } catch (\Exception $e) {
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|                 $this->record($request, 'invalidate-failed');
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| 
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|                 if ($this->options['debug']) {
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|                     throw $e;
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|                 }
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|             }
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|         }
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| 
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|         return $response;
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|     }
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| 
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|     /**
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|      * Lookups a Response from the cache for the given Request.
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|      *
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|      * When a matching cache entry is found and is fresh, it uses it as the
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|      * response without forwarding any request to the backend. When a matching
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|      * cache entry is found but is stale, it attempts to "validate" the entry with
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|      * the backend using conditional GET. When no matching cache entry is found,
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|      * it triggers "miss" processing.
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|      *
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|      * @param bool $catch Whether to process exceptions
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|      *
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|      * @throws \Exception
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|      */
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|     protected function lookup(Request $request, bool $catch = false): Response
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|     {
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|         try {
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|             $entry = $this->store->lookup($request);
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|         } catch (\Exception $e) {
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|             $this->record($request, 'lookup-failed');
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| 
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|             if ($this->options['debug']) {
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|                 throw $e;
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|             }
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| 
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|             return $this->pass($request, $catch);
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|         }
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| 
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|         if (null === $entry) {
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|             $this->record($request, 'miss');
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| 
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|             return $this->fetch($request, $catch);
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|         }
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| 
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|         if (!$this->isFreshEnough($request, $entry)) {
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|             $this->record($request, 'stale');
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| 
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|             return $this->validate($request, $entry, $catch);
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|         }
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| 
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|         if ($entry->headers->hasCacheControlDirective('no-cache')) {
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|             return $this->validate($request, $entry, $catch);
 | |
|         }
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| 
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|         $this->record($request, 'fresh');
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| 
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|         $entry->headers->set('Age', $entry->getAge());
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| 
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|         return $entry;
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|     }
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| 
 | |
|     /**
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|      * Validates that a cache entry is fresh.
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|      *
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|      * The original request is used as a template for a conditional
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|      * GET request with the backend.
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|      *
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|      * @param bool $catch Whether to process exceptions
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|      */
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|     protected function validate(Request $request, Response $entry, bool $catch = false): Response
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|     {
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|         $subRequest = clone $request;
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| 
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|         // send no head requests because we want content
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|         if ('HEAD' === $request->getMethod()) {
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|             $subRequest->setMethod('GET');
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|         }
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| 
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|         // add our cached last-modified validator
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|         if ($entry->headers->has('Last-Modified')) {
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|             $subRequest->headers->set('If-Modified-Since', $entry->headers->get('Last-Modified'));
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|         }
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| 
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|         // Add our cached etag validator to the environment.
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|         // We keep the etags from the client to handle the case when the client
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|         // has a different private valid entry which is not cached here.
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|         $cachedEtags = $entry->getEtag() ? [$entry->getEtag()] : [];
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|         $requestEtags = $request->getETags();
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|         if ($etags = array_unique(array_merge($cachedEtags, $requestEtags))) {
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|             $subRequest->headers->set('If-None-Match', implode(', ', $etags));
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|         }
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| 
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|         $response = $this->forward($subRequest, $catch, $entry);
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| 
 | |
|         if (304 == $response->getStatusCode()) {
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|             $this->record($request, 'valid');
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| 
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|             // return the response and not the cache entry if the response is valid but not cached
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|             $etag = $response->getEtag();
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|             if ($etag && \in_array($etag, $requestEtags) && !\in_array($etag, $cachedEtags)) {
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|                 return $response;
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|             }
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| 
 | |
|             $entry = clone $entry;
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|             $entry->headers->remove('Date');
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| 
 | |
|             foreach (['Date', 'Expires', 'Cache-Control', 'ETag', 'Last-Modified'] as $name) {
 | |
|                 if ($response->headers->has($name)) {
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|                     $entry->headers->set($name, $response->headers->get($name));
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|                 }
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|             }
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| 
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|             $response = $entry;
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|         } else {
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|             $this->record($request, 'invalid');
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|         }
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| 
 | |
|         if ($response->isCacheable()) {
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|             $this->store($request, $response);
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|         }
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| 
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|         return $response;
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|     }
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| 
 | |
|     /**
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|      * Unconditionally fetches a fresh response from the backend and
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|      * stores it in the cache if is cacheable.
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|      *
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|      * @param bool $catch Whether to process exceptions
 | |
|      */
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|     protected function fetch(Request $request, bool $catch = false): Response
 | |
|     {
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|         $subRequest = clone $request;
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| 
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|         // send no head requests because we want content
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|         if ('HEAD' === $request->getMethod()) {
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|             $subRequest->setMethod('GET');
 | |
|         }
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| 
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|         // avoid that the backend sends no content
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|         $subRequest->headers->remove('If-Modified-Since');
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|         $subRequest->headers->remove('If-None-Match');
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| 
 | |
|         $response = $this->forward($subRequest, $catch);
 | |
| 
 | |
|         if ($response->isCacheable()) {
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|             $this->store($request, $response);
 | |
|         }
 | |
| 
 | |
|         return $response;
 | |
|     }
 | |
| 
 | |
|     /**
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|      * Forwards the Request to the backend and returns the Response.
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|      *
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|      * All backend requests (cache passes, fetches, cache validations)
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|      * run through this method.
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|      *
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|      * @param bool          $catch Whether to catch exceptions or not
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|      * @param Response|null $entry A Response instance (the stale entry if present, null otherwise)
 | |
|      *
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|      * @return Response
 | |
|      */
 | |
|     protected function forward(Request $request, bool $catch = false, Response $entry = null)
 | |
|     {
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|         $this->surrogate?->addSurrogateCapability($request);
 | |
| 
 | |
|         // always a "master" request (as the real master request can be in cache)
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|         $response = SubRequestHandler::handle($this->kernel, $request, HttpKernelInterface::MAIN_REQUEST, $catch);
 | |
| 
 | |
|         /*
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|          * Support stale-if-error given on Responses or as a config option.
 | |
|          * RFC 7234 summarizes in Section 4.2.4 (but also mentions with the individual
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|          * Cache-Control directives) that
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|          *
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|          *      A cache MUST NOT generate a stale response if it is prohibited by an
 | |
|          *      explicit in-protocol directive (e.g., by a "no-store" or "no-cache"
 | |
|          *      cache directive, a "must-revalidate" cache-response-directive, or an
 | |
|          *      applicable "s-maxage" or "proxy-revalidate" cache-response-directive;
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|          *      see Section 5.2.2).
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|          *
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|          * https://tools.ietf.org/html/rfc7234#section-4.2.4
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|          *
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|          * We deviate from this in one detail, namely that we *do* serve entries in the
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|          * stale-if-error case even if they have a `s-maxage` Cache-Control directive.
 | |
|          */
 | |
|         if (null !== $entry
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|             && \in_array($response->getStatusCode(), [500, 502, 503, 504])
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|             && !$entry->headers->hasCacheControlDirective('no-cache')
 | |
|             && !$entry->mustRevalidate()
 | |
|         ) {
 | |
|             if (null === $age = $entry->headers->getCacheControlDirective('stale-if-error')) {
 | |
|                 $age = $this->options['stale_if_error'];
 | |
|             }
 | |
| 
 | |
|             /*
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|              * stale-if-error gives the (extra) time that the Response may be used *after* it has become stale.
 | |
|              * So we compare the time the $entry has been sitting in the cache already with the
 | |
|              * time it was fresh plus the allowed grace period.
 | |
|              */
 | |
|             if ($entry->getAge() <= $entry->getMaxAge() + $age) {
 | |
|                 $this->record($request, 'stale-if-error');
 | |
| 
 | |
|                 return $entry;
 | |
|             }
 | |
|         }
 | |
| 
 | |
|         /*
 | |
|             RFC 7231 Sect. 7.1.1.2 says that a server that does not have a reasonably accurate
 | |
|             clock MUST NOT send a "Date" header, although it MUST send one in most other cases
 | |
|             except for 1xx or 5xx responses where it MAY do so.
 | |
| 
 | |
|             Anyway, a client that received a message without a "Date" header MUST add it.
 | |
|         */
 | |
|         if (!$response->headers->has('Date')) {
 | |
|             $response->setDate(\DateTimeImmutable::createFromFormat('U', time()));
 | |
|         }
 | |
| 
 | |
|         $this->processResponseBody($request, $response);
 | |
| 
 | |
|         if ($this->isPrivateRequest($request) && !$response->headers->hasCacheControlDirective('public')) {
 | |
|             $response->setPrivate();
 | |
|         } elseif ($this->options['default_ttl'] > 0 && null === $response->getTtl() && !$response->headers->getCacheControlDirective('must-revalidate')) {
 | |
|             $response->setTtl($this->options['default_ttl']);
 | |
|         }
 | |
| 
 | |
|         return $response;
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Checks whether the cache entry is "fresh enough" to satisfy the Request.
 | |
|      */
 | |
|     protected function isFreshEnough(Request $request, Response $entry): bool
 | |
|     {
 | |
|         if (!$entry->isFresh()) {
 | |
|             return $this->lock($request, $entry);
 | |
|         }
 | |
| 
 | |
|         if ($this->options['allow_revalidate'] && null !== $maxAge = $request->headers->getCacheControlDirective('max-age')) {
 | |
|             return $maxAge > 0 && $maxAge >= $entry->getAge();
 | |
|         }
 | |
| 
 | |
|         return true;
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Locks a Request during the call to the backend.
 | |
|      *
 | |
|      * @return bool true if the cache entry can be returned even if it is staled, false otherwise
 | |
|      */
 | |
|     protected function lock(Request $request, Response $entry): bool
 | |
|     {
 | |
|         // try to acquire a lock to call the backend
 | |
|         $lock = $this->store->lock($request);
 | |
| 
 | |
|         if (true === $lock) {
 | |
|             // we have the lock, call the backend
 | |
|             return false;
 | |
|         }
 | |
| 
 | |
|         // there is already another process calling the backend
 | |
| 
 | |
|         // May we serve a stale response?
 | |
|         if ($this->mayServeStaleWhileRevalidate($entry)) {
 | |
|             $this->record($request, 'stale-while-revalidate');
 | |
| 
 | |
|             return true;
 | |
|         }
 | |
| 
 | |
|         // wait for the lock to be released
 | |
|         if ($this->waitForLock($request)) {
 | |
|             // replace the current entry with the fresh one
 | |
|             $new = $this->lookup($request);
 | |
|             $entry->headers = $new->headers;
 | |
|             $entry->setContent($new->getContent());
 | |
|             $entry->setStatusCode($new->getStatusCode());
 | |
|             $entry->setProtocolVersion($new->getProtocolVersion());
 | |
|             foreach ($new->headers->getCookies() as $cookie) {
 | |
|                 $entry->headers->setCookie($cookie);
 | |
|             }
 | |
|         } else {
 | |
|             // backend is slow as hell, send a 503 response (to avoid the dog pile effect)
 | |
|             $entry->setStatusCode(503);
 | |
|             $entry->setContent('503 Service Unavailable');
 | |
|             $entry->headers->set('Retry-After', 10);
 | |
|         }
 | |
| 
 | |
|         return true;
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Writes the Response to the cache.
 | |
|      *
 | |
|      * @throws \Exception
 | |
|      */
 | |
|     protected function store(Request $request, Response $response)
 | |
|     {
 | |
|         try {
 | |
|             $this->store->write($request, $response);
 | |
| 
 | |
|             $this->record($request, 'store');
 | |
| 
 | |
|             $response->headers->set('Age', $response->getAge());
 | |
|         } catch (\Exception $e) {
 | |
|             $this->record($request, 'store-failed');
 | |
| 
 | |
|             if ($this->options['debug']) {
 | |
|                 throw $e;
 | |
|             }
 | |
|         }
 | |
| 
 | |
|         // now that the response is cached, release the lock
 | |
|         $this->store->unlock($request);
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Restores the Response body.
 | |
|      */
 | |
|     private function restoreResponseBody(Request $request, Response $response)
 | |
|     {
 | |
|         if ($response->headers->has('X-Body-Eval')) {
 | |
|             ob_start();
 | |
| 
 | |
|             if ($response->headers->has('X-Body-File')) {
 | |
|                 include $response->headers->get('X-Body-File');
 | |
|             } else {
 | |
|                 eval('; ?>'.$response->getContent().'<?php ;');
 | |
|             }
 | |
| 
 | |
|             $response->setContent(ob_get_clean());
 | |
|             $response->headers->remove('X-Body-Eval');
 | |
|             if (!$response->headers->has('Transfer-Encoding')) {
 | |
|                 $response->headers->set('Content-Length', \strlen($response->getContent()));
 | |
|             }
 | |
|         } elseif ($response->headers->has('X-Body-File')) {
 | |
|             // Response does not include possibly dynamic content (ESI, SSI), so we need
 | |
|             // not handle the content for HEAD requests
 | |
|             if (!$request->isMethod('HEAD')) {
 | |
|                 $response->setContent(file_get_contents($response->headers->get('X-Body-File')));
 | |
|             }
 | |
|         } else {
 | |
|             return;
 | |
|         }
 | |
| 
 | |
|         $response->headers->remove('X-Body-File');
 | |
|     }
 | |
| 
 | |
|     protected function processResponseBody(Request $request, Response $response)
 | |
|     {
 | |
|         if ($this->surrogate?->needsParsing($response)) {
 | |
|             $this->surrogate->process($request, $response);
 | |
|         }
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Checks if the Request includes authorization or other sensitive information
 | |
|      * that should cause the Response to be considered private by default.
 | |
|      */
 | |
|     private function isPrivateRequest(Request $request): bool
 | |
|     {
 | |
|         foreach ($this->options['private_headers'] as $key) {
 | |
|             $key = strtolower(str_replace('HTTP_', '', $key));
 | |
| 
 | |
|             if ('cookie' === $key) {
 | |
|                 if (\count($request->cookies->all())) {
 | |
|                     return true;
 | |
|                 }
 | |
|             } elseif ($request->headers->has($key)) {
 | |
|                 return true;
 | |
|             }
 | |
|         }
 | |
| 
 | |
|         return false;
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Records that an event took place.
 | |
|      */
 | |
|     private function record(Request $request, string $event)
 | |
|     {
 | |
|         $this->traces[$this->getTraceKey($request)][] = $event;
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Calculates the key we use in the "trace" array for a given request.
 | |
|      */
 | |
|     private function getTraceKey(Request $request): string
 | |
|     {
 | |
|         $path = $request->getPathInfo();
 | |
|         if ($qs = $request->getQueryString()) {
 | |
|             $path .= '?'.$qs;
 | |
|         }
 | |
| 
 | |
|         return $request->getMethod().' '.$path;
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Checks whether the given (cached) response may be served as "stale" when a revalidation
 | |
|      * is currently in progress.
 | |
|      */
 | |
|     private function mayServeStaleWhileRevalidate(Response $entry): bool
 | |
|     {
 | |
|         $timeout = $entry->headers->getCacheControlDirective('stale-while-revalidate');
 | |
|         $timeout ??= $this->options['stale_while_revalidate'];
 | |
| 
 | |
|         return abs($entry->getTtl() ?? 0) < $timeout;
 | |
|     }
 | |
| 
 | |
|     /**
 | |
|      * Waits for the store to release a locked entry.
 | |
|      */
 | |
|     private function waitForLock(Request $request): bool
 | |
|     {
 | |
|         $wait = 0;
 | |
|         while ($this->store->isLocked($request) && $wait < 100) {
 | |
|             usleep(50000);
 | |
|             ++$wait;
 | |
|         }
 | |
| 
 | |
|         return $wait < 100;
 | |
|     }
 | |
| }
 | 
