diff vendor/symfony/http-kernel/HttpCache/HttpCache.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/symfony/http-kernel/HttpCache/HttpCache.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,693 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[e-mail]>
+ *
+ * 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\HttpKernel\HttpKernelInterface;
+use Symfony\Component\HttpKernel\TerminableInterface;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * Cache provides HTTP caching.
+ *
+ * @author Fabien Potencier <[e-mail]>
+ */
+class HttpCache implements HttpKernelInterface, TerminableInterface
+{
+    private $kernel;
+    private $store;
+    private $request;
+    private $surrogate;
+    private $surrogateCacheStrategy;
+    private $options = array();
+    private $traces = array();
+
+    /**
+     * Constructor.
+     *
+     * The available options are:
+     *
+     *   * debug:                 If true, the traces are added as a HTTP header to ease debugging
+     *
+     *   * default_ttl            The number of seconds that a cache entry should be considered
+     *                            fresh when no explicit freshness information is provided in
+     *                            a response. Explicit Cache-Control or Expires headers
+     *                            override this value. (default: 0)
+     *
+     *   * private_headers        Set of request headers that trigger "private" cache-control behavior
+     *                            on responses that don't explicitly state whether the response is
+     *                            public or private via a Cache-Control directive. (default: Authorization and Cookie)
+     *
+     *   * allow_reload           Specifies whether the client can force a cache reload by including a
+     *                            Cache-Control "no-cache" directive in the request. Set it to ``true``
+     *                            for compliance with RFC 2616. (default: false)
+     *
+     *   * allow_revalidate       Specifies whether the client can force a cache revalidate by including
+     *                            a Cache-Control "max-age=0" directive in the request. Set it to ``true``
+     *                            for compliance with RFC 2616. (default: false)
+     *
+     *   * stale_while_revalidate Specifies the default number of seconds (the granularity is the second as the
+     *                            Response TTL precision is a second) during which the cache can immediately return
+     *                            a stale response while it revalidates it in the background (default: 2).
+     *                            This setting is overridden by the stale-while-revalidate HTTP Cache-Control
+     *                            extension (see RFC 5861).
+     *
+     *   * stale_if_error         Specifies the default number of seconds (the granularity is the second) during which
+     *                            the cache can serve a stale response when an error is encountered (default: 60).
+     *                            This setting is overridden by the stale-if-error HTTP Cache-Control extension
+     *                            (see RFC 5861).
+     *
+     * @param HttpKernelInterface $kernel    An HttpKernelInterface instance
+     * @param StoreInterface      $store     A Store instance
+     * @param SurrogateInterface  $surrogate A SurrogateInterface instance
+     * @param array               $options   An array of options
+     */
+    public function __construct(HttpKernelInterface $kernel, StoreInterface $store, SurrogateInterface $surrogate = null, array $options = array())
+    {
+        $this->store = $store;
+        $this->kernel = $kernel;
+        $this->surrogate = $surrogate;
+
+        // needed in case there is a fatal error because the backend is too slow to respond
+        register_shutdown_function(array($this->store, 'cleanup'));
+
+        $this->options = array_merge(array(
+            'debug' => false,
+            'default_ttl' => 0,
+            'private_headers' => array('Authorization', 'Cookie'),
+            'allow_reload' => false,
+            'allow_revalidate' => false,
+            'stale_while_revalidate' => 2,
+            'stale_if_error' => 60,
+        ), $options);
+    }
+
+    /**
+     * Gets the current store.
+     *
+     * @return StoreInterface $store A StoreInterface instance
+     */
+    public function getStore()
+    {
+        return $this->store;
+    }
+
+    /**
+     * Returns an array of events that took place during processing of the last request.
+     *
+     * @return array An array of events
+     */
+    public function getTraces()
+    {
+        return $this->traces;
+    }
+
+    /**
+     * Returns a log message for the events of the last request processing.
+     *
+     * @return string A log message
+     */
+    public function getLog()
+    {
+        $log = array();
+        foreach ($this->traces as $request => $traces) {
+            $log[] = sprintf('%s: %s', $request, implode(', ', $traces));
+        }
+
+        return implode('; ', $log);
+    }
+
+    /**
+     * Gets the Request instance associated with the master request.
+     *
+     * @return Request A Request instance
+     */
+    public function getRequest()
+    {
+        return $this->request;
+    }
+
+    /**
+     * Gets the Kernel instance.
+     *
+     * @return HttpKernelInterface An HttpKernelInterface instance
+     */
+    public function getKernel()
+    {
+        return $this->kernel;
+    }
+
+    /**
+     * Gets the Surrogate instance.
+     *
+     * @return SurrogateInterface A Surrogate instance
+     *
+     * @throws \LogicException
+     */
+    public function getSurrogate()
+    {
+        return $this->surrogate;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function handle(Request $request, $type = HttpKernelInterface::MASTER_REQUEST, $catch = true)
+    {
+        // FIXME: catch exceptions and implement a 500 error page here? -> in Varnish, there is a built-in error page mechanism
+        if (HttpKernelInterface::MASTER_REQUEST === $type) {
+            $this->traces = array();
+            $this->request = $request;
+            if (null !== $this->surrogate) {
+                $this->surrogateCacheStrategy = $this->surrogate->createCacheStrategy();
+            }
+        }
+
+        $path = $request->getPathInfo();
+        if ($qs = $request->getQueryString()) {
+            $path .= '?'.$qs;
+        }
+        $this->traces[$request->getMethod().' '.$path] = array();
+
+        if (!$request->isMethodSafe(false)) {
+            $response = $this->invalidate($request, $catch);
+        } elseif ($request->headers->has('expect') || !$request->isMethodCacheable()) {
+            $response = $this->pass($request, $catch);
+        } else {
+            $response = $this->lookup($request, $catch);
+        }
+
+        $this->restoreResponseBody($request, $response);
+
+        $response->setDate(\DateTime::createFromFormat('U', time(), new \DateTimeZone('UTC')));
+
+        if (HttpKernelInterface::MASTER_REQUEST === $type && $this->options['debug']) {
+            $response->headers->set('X-Symfony-Cache', $this->getLog());
+        }
+
+        if (null !== $this->surrogate) {
+            if (HttpKernelInterface::MASTER_REQUEST === $type) {
+                $this->surrogateCacheStrategy->update($response);
+            } else {
+                $this->surrogateCacheStrategy->add($response);
+            }
+        }
+
+        $response->prepare($request);
+
+        $response->isNotModified($request);
+
+        return $response;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function terminate(Request $request, Response $response)
+    {
+        if ($this->getKernel() instanceof TerminableInterface) {
+            $this->getKernel()->terminate($request, $response);
+        }
+    }
+
+    /**
+     * Forwards the Request to the backend without storing the Response in the cache.
+     *
+     * @param Request $request A Request instance
+     * @param bool    $catch   Whether to process exceptions
+     *
+     * @return Response A Response instance
+     */
+    protected function pass(Request $request, $catch = false)
+    {
+        $this->record($request, 'pass');
+
+        return $this->forward($request, $catch);
+    }
+
+    /**
+     * Invalidates non-safe methods (like POST, PUT, and DELETE).
+     *
+     * @param Request $request A Request instance
+     * @param bool    $catch   Whether to process exceptions
+     *
+     * @return Response A Response instance
+     *
+     * @throws \Exception
+     *
+     * @see RFC2616 13.10
+     */
+    protected function invalidate(Request $request, $catch = false)
+    {
+        $response = $this->pass($request, $catch);
+
+        // invalidate only when the response is successful
+        if ($response->isSuccessful() || $response->isRedirect()) {
+            try {
+                $this->store->invalidate($request);
+
+                // As per the RFC, invalidate Location and Content-Location URLs if present
+                foreach (array('Location', 'Content-Location') as $header) {
+                    if ($uri = $response->headers->get($header)) {
+                        $subRequest = Request::create($uri, 'get', array(), array(), array(), $request->server->all());
+
+                        $this->store->invalidate($subRequest);
+                    }
+                }
+
+                $this->record($request, 'invalidate');
+            } catch (\Exception $e) {
+                $this->record($request, 'invalidate-failed');
+
+                if ($this->options['debug']) {
+                    throw $e;
+                }
+            }
+        }
+
+        return $response;
+    }
+
+    /**
+     * Lookups a Response from the cache for the given Request.
+     *
+     * When a matching cache entry is found and is fresh, it uses it as the
+     * response without forwarding any request to the backend. When a matching
+     * cache entry is found but is stale, it attempts to "validate" the entry with
+     * the backend using conditional GET. When no matching cache entry is found,
+     * it triggers "miss" processing.
+     *
+     * @param Request $request A Request instance
+     * @param bool    $catch   whether to process exceptions
+     *
+     * @return Response A Response instance
+     *
+     * @throws \Exception
+     */
+    protected function lookup(Request $request, $catch = false)
+    {
+        // if allow_reload and no-cache Cache-Control, allow a cache reload
+        if ($this->options['allow_reload'] && $request->isNoCache()) {
+            $this->record($request, 'reload');
+
+            return $this->fetch($request, $catch);
+        }
+
+        try {
+            $entry = $this->store->lookup($request);
+        } catch (\Exception $e) {
+            $this->record($request, 'lookup-failed');
+
+            if ($this->options['debug']) {
+                throw $e;
+            }
+
+            return $this->pass($request, $catch);
+        }
+
+        if (null === $entry) {
+            $this->record($request, 'miss');
+
+            return $this->fetch($request, $catch);
+        }
+
+        if (!$this->isFreshEnough($request, $entry)) {
+            $this->record($request, 'stale');
+
+            return $this->validate($request, $entry, $catch);
+        }
+
+        $this->record($request, 'fresh');
+
+        $entry->headers->set('Age', $entry->getAge());
+
+        return $entry;
+    }
+
+    /**
+     * Validates that a cache entry is fresh.
+     *
+     * The original request is used as a template for a conditional
+     * GET request with the backend.
+     *
+     * @param Request  $request A Request instance
+     * @param Response $entry   A Response instance to validate
+     * @param bool     $catch   Whether to process exceptions
+     *
+     * @return Response A Response instance
+     */
+    protected function validate(Request $request, Response $entry, $catch = false)
+    {
+        $subRequest = clone $request;
+
+        // send no head requests because we want content
+        if ('HEAD' === $request->getMethod()) {
+            $subRequest->setMethod('GET');
+        }
+
+        // add our cached last-modified validator
+        $subRequest->headers->set('if_modified_since', $entry->headers->get('Last-Modified'));
+
+        // Add our cached etag validator to the environment.
+        // We keep the etags from the client to handle the case when the client
+        // has a different private valid entry which is not cached here.
+        $cachedEtags = $entry->getEtag() ? array($entry->getEtag()) : array();
+        $requestEtags = $request->getETags();
+        if ($etags = array_unique(array_merge($cachedEtags, $requestEtags))) {
+            $subRequest->headers->set('if_none_match', implode(', ', $etags));
+        }
+
+        $response = $this->forward($subRequest, $catch, $entry);
+
+        if (304 == $response->getStatusCode()) {
+            $this->record($request, 'valid');
+
+            // return the response and not the cache entry if the response is valid but not cached
+            $etag = $response->getEtag();
+            if ($etag && in_array($etag, $requestEtags) && !in_array($etag, $cachedEtags)) {
+                return $response;
+            }
+
+            $entry = clone $entry;
+            $entry->headers->remove('Date');
+
+            foreach (array('Date', 'Expires', 'Cache-Control', 'ETag', 'Last-Modified') as $name) {
+                if ($response->headers->has($name)) {
+                    $entry->headers->set($name, $response->headers->get($name));
+                }
+            }
+
+            $response = $entry;
+        } else {
+            $this->record($request, 'invalid');
+        }
+
+        if ($response->isCacheable()) {
+            $this->store($request, $response);
+        }
+
+        return $response;
+    }
+
+    /**
+     * Forwards the Request to the backend and determines whether the response should be stored.
+     *
+     * This methods is triggered when the cache missed or a reload is required.
+     *
+     * @param Request $request A Request instance
+     * @param bool    $catch   whether to process exceptions
+     *
+     * @return Response A Response instance
+     */
+    protected function fetch(Request $request, $catch = false)
+    {
+        $subRequest = clone $request;
+
+        // send no head requests because we want content
+        if ('HEAD' === $request->getMethod()) {
+            $subRequest->setMethod('GET');
+        }
+
+        // avoid that the backend sends no content
+        $subRequest->headers->remove('if_modified_since');
+        $subRequest->headers->remove('if_none_match');
+
+        $response = $this->forward($subRequest, $catch);
+
+        if ($response->isCacheable()) {
+            $this->store($request, $response);
+        }
+
+        return $response;
+    }
+
+    /**
+     * Forwards the Request to the backend and returns the Response.
+     *
+     * @param Request  $request A Request instance
+     * @param bool     $catch   Whether to catch exceptions or not
+     * @param Response $entry   A Response instance (the stale entry if present, null otherwise)
+     *
+     * @return Response A Response instance
+     */
+    protected function forward(Request $request, $catch = false, Response $entry = null)
+    {
+        if ($this->surrogate) {
+            $this->surrogate->addSurrogateCapability($request);
+        }
+
+        // modify the X-Forwarded-For header if needed
+        $forwardedFor = $request->headers->get('X-Forwarded-For');
+        if ($forwardedFor) {
+            $request->headers->set('X-Forwarded-For', $forwardedFor.', '.$request->server->get('REMOTE_ADDR'));
+        } else {
+            $request->headers->set('X-Forwarded-For', $request->server->get('REMOTE_ADDR'));
+        }
+
+        // fix the client IP address by setting it to 127.0.0.1 as HttpCache
+        // is always called from the same process as the backend.
+        $request->server->set('REMOTE_ADDR', '127.0.0.1');
+
+        // make sure HttpCache is a trusted proxy
+        if (!in_array('127.0.0.1', $trustedProxies = Request::getTrustedProxies())) {
+            $trustedProxies[] = '127.0.0.1';
+            Request::setTrustedProxies($trustedProxies, method_exists('Request', 'getTrustedHeaderSet') ? Request::getTrustedHeaderSet() : -1);
+        }
+
+        // always a "master" request (as the real master request can be in cache)
+        $response = $this->kernel->handle($request, HttpKernelInterface::MASTER_REQUEST, $catch);
+        // FIXME: we probably need to also catch exceptions if raw === true
+
+        // we don't implement the stale-if-error on Requests, which is nonetheless part of the RFC
+        if (null !== $entry && in_array($response->getStatusCode(), array(500, 502, 503, 504))) {
+            if (null === $age = $entry->headers->getCacheControlDirective('stale-if-error')) {
+                $age = $this->options['stale_if_error'];
+            }
+
+            if (abs($entry->getTtl()) < $age) {
+                $this->record($request, 'stale-if-error');
+
+                return $entry;
+            }
+        }
+
+        $this->processResponseBody($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.
+     *
+     * @param Request  $request A Request instance
+     * @param Response $entry   A Response instance
+     *
+     * @return bool true if the cache entry if fresh enough, false otherwise
+     */
+    protected function isFreshEnough(Request $request, Response $entry)
+    {
+        if (!$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.
+     *
+     * @param Request  $request A Request instance
+     * @param Response $entry   A Response instance
+     *
+     * @return bool true if the cache entry can be returned even if it is staled, false otherwise
+     */
+    protected function lock(Request $request, Response $entry)
+    {
+        // try to acquire a lock to call the backend
+        $lock = $this->store->lock($request);
+
+        // there is already another process calling the backend
+        if (true !== $lock) {
+            // check if we can serve the stale entry
+            if (null === $age = $entry->headers->getCacheControlDirective('stale-while-revalidate')) {
+                $age = $this->options['stale_while_revalidate'];
+            }
+
+            if (abs($entry->getTtl()) < $age) {
+                $this->record($request, 'stale-while-revalidate');
+
+                // server the stale response while there is a revalidation
+                return true;
+            }
+
+            // wait for the lock to be released
+            $wait = 0;
+            while ($this->store->isLocked($request) && $wait < 5000000) {
+                usleep(50000);
+                $wait += 50000;
+            }
+
+            if ($wait < 5000000) {
+                // 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;
+        }
+
+        // we have the lock, call the backend
+        return false;
+    }
+
+    /**
+     * Writes the Response to the cache.
+     *
+     * @param Request  $request  A Request instance
+     * @param Response $response A Response instance
+     *
+     * @throws \Exception
+     */
+    protected function store(Request $request, Response $response)
+    {
+        if (!$response->headers->has('Date')) {
+            $response->setDate(\DateTime::createFromFormat('U', time()));
+        }
+        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.
+     *
+     * @param Request  $request  A Request instance
+     * @param Response $response A Response instance
+     */
+    private function restoreResponseBody(Request $request, Response $response)
+    {
+        if ($request->isMethod('HEAD') || 304 === $response->getStatusCode()) {
+            $response->setContent(null);
+            $response->headers->remove('X-Body-Eval');
+            $response->headers->remove('X-Body-File');
+
+            return;
+        }
+
+        if ($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')) {
+            $response->setContent(file_get_contents($response->headers->get('X-Body-File')));
+        } else {
+            return;
+        }
+
+        $response->headers->remove('X-Body-File');
+    }
+
+    protected function processResponseBody(Request $request, Response $response)
+    {
+        if (null !== $this->surrogate && $this->surrogate->needsParsing($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.
+     *
+     * @param Request $request A Request instance
+     *
+     * @return bool true if the Request is private, false otherwise
+     */
+    private function isPrivateRequest(Request $request)
+    {
+        foreach ($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.
+     *
+     * @param Request $request A Request instance
+     * @param string  $event   The event name
+     */
+    private function record(Request $request, $event)
+    {
+        $path = $request->getPathInfo();
+        if ($qs = $request->getQueryString()) {
+            $path .= '?'.$qs;
+        }
+        $this->traces[$request->getMethod().' '.$path][] = $event;
+    }
+}