/web/core/modules/page_cache/src/StackMiddleware/PageCache.php
PHP | 365 lines | 127 code | 32 blank | 206 comment | 26 complexity | 49eed6cbe9e27a699b5d30c45965058a MD5 | raw file
- <?php
- namespace Drupal\page_cache\StackMiddleware;
- use Drupal\Core\Cache\Cache;
- use Drupal\Core\Cache\CacheableResponseInterface;
- use Drupal\Core\Cache\CacheBackendInterface;
- use Drupal\Core\PageCache\RequestPolicyInterface;
- use Drupal\Core\PageCache\ResponsePolicyInterface;
- use Drupal\Core\Site\Settings;
- use Symfony\Component\HttpFoundation\BinaryFileResponse;
- use Symfony\Component\HttpFoundation\Request;
- use Symfony\Component\HttpFoundation\Response;
- use Symfony\Component\HttpFoundation\StreamedResponse;
- use Symfony\Component\HttpKernel\HttpKernelInterface;
- /**
- * Executes the page caching before the main kernel takes over the request.
- */
- class PageCache implements HttpKernelInterface {
- /**
- * The wrapped HTTP kernel.
- *
- * @var \Symfony\Component\HttpKernel\HttpKernelInterface
- */
- protected $httpKernel;
- /**
- * The cache bin.
- *
- * @var \Drupal\Core\Cache\CacheBackendInterface
- */
- protected $cache;
- /**
- * A policy rule determining the cacheability of a request.
- *
- * @var \Drupal\Core\PageCache\RequestPolicyInterface
- */
- protected $requestPolicy;
- /**
- * A policy rule determining the cacheability of the response.
- *
- * @var \Drupal\Core\PageCache\ResponsePolicyInterface
- */
- protected $responsePolicy;
- /**
- * The cache ID for the (master) request.
- *
- * @var string
- */
- protected $cid;
- /**
- * Constructs a PageCache object.
- *
- * @param \Symfony\Component\HttpKernel\HttpKernelInterface $http_kernel
- * The decorated kernel.
- * @param \Drupal\Core\Cache\CacheBackendInterface $cache
- * The cache bin.
- * @param \Drupal\Core\PageCache\RequestPolicyInterface $request_policy
- * A policy rule determining the cacheability of a request.
- * @param \Drupal\Core\PageCache\ResponsePolicyInterface $response_policy
- * A policy rule determining the cacheability of the response.
- */
- public function __construct(HttpKernelInterface $http_kernel, CacheBackendInterface $cache, RequestPolicyInterface $request_policy, ResponsePolicyInterface $response_policy) {
- $this->httpKernel = $http_kernel;
- $this->cache = $cache;
- $this->requestPolicy = $request_policy;
- $this->responsePolicy = $response_policy;
- }
- /**
- * {@inheritdoc}
- */
- public function handle(Request $request, $type = self::MASTER_REQUEST, $catch = TRUE): Response {
- // Only allow page caching on master request.
- if ($type === static::MASTER_REQUEST && $this->requestPolicy->check($request) === RequestPolicyInterface::ALLOW) {
- $response = $this->lookup($request, $type, $catch);
- }
- else {
- $response = $this->pass($request, $type, $catch);
- }
- return $response;
- }
- /**
- * Sidesteps the page cache and directly forwards a request to the backend.
- *
- * @param \Symfony\Component\HttpFoundation\Request $request
- * A request object.
- * @param int $type
- * The type of the request (one of HttpKernelInterface::MASTER_REQUEST or
- * HttpKernelInterface::SUB_REQUEST)
- * @param bool $catch
- * Whether to catch exceptions or not
- *
- * @returns \Symfony\Component\HttpFoundation\Response $response
- * A response object.
- */
- protected function pass(Request $request, $type = self::MASTER_REQUEST, $catch = TRUE) {
- return $this->httpKernel->handle($request, $type, $catch);
- }
- /**
- * Retrieves a response from the cache or fetches it from the backend.
- *
- * @param \Symfony\Component\HttpFoundation\Request $request
- * A request object.
- * @param int $type
- * The type of the request (one of HttpKernelInterface::MASTER_REQUEST or
- * HttpKernelInterface::SUB_REQUEST)
- * @param bool $catch
- * Whether to catch exceptions or not
- *
- * @returns \Symfony\Component\HttpFoundation\Response $response
- * A response object.
- */
- protected function lookup(Request $request, $type = self::MASTER_REQUEST, $catch = TRUE) {
- if ($response = $this->get($request)) {
- $response->headers->set('X-Drupal-Cache', 'HIT');
- }
- else {
- $response = $this->fetch($request, $type, $catch);
- }
- // Only allow caching in the browser and prevent that the response is stored
- // by an external proxy server when the following conditions apply:
- // 1. There is a session cookie on the request.
- // 2. The Vary: Cookie header is on the response.
- // 3. The Cache-Control header does not contain the no-cache directive.
- if ($request->cookies->has(session_name()) &&
- in_array('Cookie', $response->getVary()) &&
- !$response->headers->hasCacheControlDirective('no-cache')) {
- $response->setPrivate();
- }
- // Perform HTTP revalidation.
- // @todo Use Response::isNotModified() as
- // per https://www.drupal.org/node/2259489.
- $last_modified = $response->getLastModified();
- if ($last_modified) {
- // See if the client has provided the required HTTP headers.
- $if_modified_since = $request->server->has('HTTP_IF_MODIFIED_SINCE') ? strtotime($request->server->get('HTTP_IF_MODIFIED_SINCE')) : FALSE;
- $if_none_match = $request->server->has('HTTP_IF_NONE_MATCH') ? stripslashes($request->server->get('HTTP_IF_NONE_MATCH')) : FALSE;
- if ($if_modified_since && $if_none_match
- // etag must match.
- && $if_none_match == $response->getEtag()
- // if-modified-since must match.
- && $if_modified_since == $last_modified->getTimestamp()) {
- $response->setStatusCode(304);
- $response->setContent(NULL);
- // In the case of a 304 response, certain headers must be sent, and the
- // remaining may not (see RFC 2616, section 10.3.5).
- foreach (array_keys($response->headers->all()) as $name) {
- if (!in_array($name, ['content-location', 'expires', 'cache-control', 'vary'])) {
- $response->headers->remove($name);
- }
- }
- }
- }
- return $response;
- }
- /**
- * Fetches a response from the backend and stores it in the cache.
- *
- * @see drupal_page_header()
- *
- * @param \Symfony\Component\HttpFoundation\Request $request
- * A request object.
- * @param int $type
- * The type of the request (one of HttpKernelInterface::MASTER_REQUEST or
- * HttpKernelInterface::SUB_REQUEST)
- * @param bool $catch
- * Whether to catch exceptions or not
- *
- * @returns \Symfony\Component\HttpFoundation\Response $response
- * A response object.
- */
- protected function fetch(Request $request, $type = self::MASTER_REQUEST, $catch = TRUE) {
- /** @var \Symfony\Component\HttpFoundation\Response $response */
- $response = $this->httpKernel->handle($request, $type, $catch);
- // Only set the 'X-Drupal-Cache' header if caching is allowed for this
- // response.
- if ($this->storeResponse($request, $response)) {
- $response->headers->set('X-Drupal-Cache', 'MISS');
- }
- return $response;
- }
- /**
- * Stores a response in the page cache.
- *
- * @param \Symfony\Component\HttpFoundation\Request $request
- * A request object.
- * @param \Symfony\Component\HttpFoundation\Response $response
- * A response object that should be stored in the page cache.
- *
- * @returns bool
- */
- protected function storeResponse(Request $request, Response $response) {
- // Drupal's primary cache invalidation architecture is cache tags: any
- // response that varies by a configuration value or data in a content
- // entity should have cache tags, to allow for instant cache invalidation
- // when that data is updated. However, HTTP does not standardize how to
- // encode cache tags in a response. Different CDNs implement their own
- // approaches, and configurable reverse proxies (e.g., Varnish) allow for
- // custom implementations. To keep Drupal's internal page cache simple, we
- // only cache CacheableResponseInterface responses, since those provide a
- // defined API for retrieving cache tags. For responses that do not
- // implement CacheableResponseInterface, there's no easy way to distinguish
- // responses that truly don't depend on any site data from responses that
- // contain invalidation information customized to a particular proxy or
- // CDN.
- // - Drupal modules are encouraged to use CacheableResponseInterface
- // responses where possible and to leave the encoding of that information
- // into response headers to the corresponding proxy/CDN integration
- // modules.
- // - Custom applications that wish to provide internal page cache support
- // for responses that do not implement CacheableResponseInterface may do
- // so by replacing/extending this middleware service or adding another
- // one.
- if (!$response instanceof CacheableResponseInterface) {
- return FALSE;
- }
- // Currently it is not possible to cache binary file or streamed responses:
- // https://github.com/symfony/symfony/issues/9128#issuecomment-25088678.
- // Therefore exclude them, even for subclasses that implement
- // CacheableResponseInterface.
- if ($response instanceof BinaryFileResponse || $response instanceof StreamedResponse) {
- return FALSE;
- }
- // Allow policy rules to further restrict which responses to cache.
- if ($this->responsePolicy->check($response, $request) === ResponsePolicyInterface::DENY) {
- return FALSE;
- }
- $request_time = $request->server->get('REQUEST_TIME');
- // The response passes all of the above checks, so cache it. Page cache
- // entries default to Cache::PERMANENT since they will be expired via cache
- // tags locally. Because of this, page cache ignores max age.
- // - Get the tags from CacheableResponseInterface per the earlier comments.
- // - Get the time expiration from the Expires header, rather than the
- // interface, but see https://www.drupal.org/node/2352009 about possibly
- // changing that.
- $expire = 0;
- // 403 and 404 responses can fill non-LRU cache backends and generally are
- // likely to have a low cache hit rate. So do not cache them permanently.
- if ($response->isClientError()) {
- // Cache for an hour by default. If the 'cache_ttl_4xx' setting is
- // set to 0 then do not cache the response.
- $cache_ttl_4xx = Settings::get('cache_ttl_4xx', 3600);
- if ($cache_ttl_4xx > 0) {
- $expire = $request_time + $cache_ttl_4xx;
- }
- }
- // The getExpires method could return NULL if Expires header is not set, so
- // the returned value needs to be checked before calling getTimestamp.
- elseif ($expires = $response->getExpires()) {
- $date = $expires->getTimestamp();
- $expire = ($date > $request_time) ? $date : Cache::PERMANENT;
- }
- else {
- $expire = Cache::PERMANENT;
- }
- if ($expire === Cache::PERMANENT || $expire > $request_time) {
- $tags = $response->getCacheableMetadata()->getCacheTags();
- $this->set($request, $response, $expire, $tags);
- }
- return TRUE;
- }
- /**
- * Returns a response object from the page cache.
- *
- * @param \Symfony\Component\HttpFoundation\Request $request
- * A request object.
- * @param bool $allow_invalid
- * (optional) If TRUE, a cache item may be returned even if it is expired or
- * has been invalidated. Such items may sometimes be preferred, if the
- * alternative is recalculating the value stored in the cache, especially
- * if another concurrent request is already recalculating the same value.
- * The "valid" property of the returned object indicates whether the item is
- * valid or not. Defaults to FALSE.
- *
- * @return \Symfony\Component\HttpFoundation\Response|false
- * The cached response or FALSE on failure.
- */
- protected function get(Request $request, $allow_invalid = FALSE) {
- $cid = $this->getCacheId($request);
- if ($cache = $this->cache->get($cid, $allow_invalid)) {
- return $cache->data;
- }
- return FALSE;
- }
- /**
- * Stores a response object in the page cache.
- *
- * @param \Symfony\Component\HttpFoundation\Request $request
- * A request object.
- * @param \Symfony\Component\HttpFoundation\Response $response
- * The response to store in the cache.
- * @param int $expire
- * One of the following values:
- * - CacheBackendInterface::CACHE_PERMANENT: Indicates that the item should
- * not be removed unless it is deleted explicitly.
- * - A Unix timestamp: Indicates that the item will be considered invalid
- * after this time, i.e. it will not be returned by get() unless
- * $allow_invalid has been set to TRUE. When the item has expired, it may
- * be permanently deleted by the garbage collector at any time.
- * @param array $tags
- * An array of tags to be stored with the cache item. These should normally
- * identify objects used to build the cache item, which should trigger
- * cache invalidation when updated. For example if a cached item represents
- * a node, both the node ID and the author's user ID might be passed in as
- * tags. For example array('node' => array(123), 'user' => array(92)).
- */
- protected function set(Request $request, Response $response, $expire, array $tags) {
- $cid = $this->getCacheId($request);
- $this->cache->set($cid, $response, $expire, $tags);
- }
- /**
- * Gets the page cache ID for this request.
- *
- * @param \Symfony\Component\HttpFoundation\Request $request
- * A request object.
- *
- * @return string
- * The cache ID for this request.
- */
- protected function getCacheId(Request $request) {
- // Once a cache ID is determined for the request, reuse it for the duration
- // of the request. This ensures that when the cache is written, it is only
- // keyed on request data that was available when it was read. For example,
- // the request format might be NULL during cache lookup and then set during
- // routing, in which case we want to key on NULL during writing, since that
- // will be the value during lookups for subsequent requests.
- if (!isset($this->cid)) {
- $cid_parts = [
- $request->getSchemeAndHttpHost() . $request->getRequestUri(),
- $request->getRequestFormat(NULL),
- ];
- $this->cid = implode(':', $cid_parts);
- }
- return $this->cid;
- }
- }