/**
* Fetches a response from the backend and stores it in the cache.
*
* If page_compression is enabled, a gzipped version of the page is stored in
* the cache to avoid compressing the output on each request. The cache entry
* is unzipped in the relatively rare event that the page is requested by a
* client without gzip support.
*
* Page compression requires the PHP zlib extension
* (http://php.net/manual/ref.zlib.php).
*
* @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)
{
$response = $this->httpKernel->handle($request, $type, $catch);
// Currently it is not possible to cache some types of responses. Therefore
// exclude binary file responses (generated files, e.g. images with image
// styles) and streamed responses (files directly read from the disk).
// see: https://github.com/symfony/symfony/issues/9128#issuecomment-25088678
if ($response instanceof BinaryFileResponse || $response instanceof StreamedResponse) {
return $response;
}
if ($this->responsePolicy->check($response, $request) === ResponsePolicyInterface::DENY) {
return $response;
}
// Check if the current page may be compressed.
if (extension_loaded('zlib') && !$response->headers->get('Content-Encoding') && $this->config('system.performance')->get('response.gzip')) {
$content = $response->getContent();
if ($content) {
$response->setContent(gzencode($content, 9, FORCE_GZIP));
$response->headers->set('Content-Encoding', 'gzip');
}
// When page compression is enabled, ensure that proxy caches will record
// and deliver different versions of a page depending on whether the
// client supports gzip or not.
$response->setVary('Accept-Encoding', FALSE);
}
// Use the actual timestamp from an Expires header, if available.
$date = $response->getExpires();
$expire = $date > new \DateTime() ? $date->getTimestamp() : Cache::PERMANENT;
$tags = explode(' ', $response->headers->get('X-Drupal-Cache-Tags'));
$this->set($request, $response, $expire, $tags);
// Mark response as a cache miss.
$response->headers->set('X-Drupal-Cache', 'MISS');
return $response;
}
/**
* Sets extra headers on successful responses.
*
* @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
* The event to process.
*/
public function onRespond(FilterResponseEvent $event)
{
if (!$event->isMasterRequest()) {
return;
}
$request = $event->getRequest();
$response = $event->getResponse();
// Set the X-UA-Compatible HTTP header to force IE to use the most recent
// rendering engine.
$response->headers->set('X-UA-Compatible', 'IE=edge', FALSE);
// Set the Content-language header.
$response->headers->set('Content-language', $this->languageManager->getCurrentLanguage()->getId());
// Prevent browsers from sniffing a response and picking a MIME type
// different from the declared content-type, since that can lead to
// XSS and other vulnerabilities.
// https://www.owasp.org/index.php/List_of_useful_HTTP_headers
$response->headers->set('X-Content-Type-Options', 'nosniff', FALSE);
$response->headers->set('X-Frame-Options', 'SAMEORIGIN', FALSE);
// If the current response isn't an implementation of the
// CacheableResponseInterface, we assume that a Response is either
// explicitly not cacheable or that caching headers are already set in
// another place.
if (!$response instanceof CacheableResponseInterface) {
if (!$this->isCacheControlCustomized($response)) {
$this->setResponseNotCacheable($response, $request);
}
// HTTP/1.0 proxies do not support the Vary header, so prevent any caching
// by sending an Expires date in the past. HTTP/1.1 clients ignore the
// Expires header if a Cache-Control: max-age directive is specified (see
// RFC 2616, section 14.9.3).
if (!$response->headers->has('Expires')) {
$this->setExpiresNoCache($response);
}
return;
}
if ($this->debugCacheabilityHeaders) {
// Expose the cache contexts and cache tags associated with this page in a
// X-Drupal-Cache-Contexts and X-Drupal-Cache-Tags header respectively.
$response_cacheability = $response->getCacheableMetadata();
$response->headers->set('X-Drupal-Cache-Tags', implode(' ', $response_cacheability->getCacheTags()));
$response->headers->set('X-Drupal-Cache-Contexts', implode(' ', $this->cacheContextsManager->optimizeTokens($response_cacheability->getCacheContexts())));
}
$is_cacheable = $this->requestPolicy->check($request) === RequestPolicyInterface::ALLOW && $this->responsePolicy->check($response, $request) !== ResponsePolicyInterface::DENY;
// Add headers necessary to specify whether the response should be cached by
// proxies and/or the browser.
if ($is_cacheable && $this->config->get('cache.page.max_age') > 0) {
if (!$this->isCacheControlCustomized($response)) {
// Only add the default Cache-Control header if the controller did not
// specify one on the response.
$this->setResponseCacheable($response, $request);
}
} else {
// If either the policy forbids caching or the sites configuration does
// not allow to add a max-age directive, then enforce a Cache-Control
// header declaring the response as not cacheable.
$this->setResponseNotCacheable($response, $request);
}
}
/**
* Sets extra headers on successful responses.
*
* @param Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
* The event to process.
*/
public function onRespond(FilterResponseEvent $event)
{
if (!$event->isMasterRequest()) {
return;
}
$request = $event->getRequest();
$response = $event->getResponse();
// Set the X-UA-Compatible HTTP header to force IE to use the most recent
// rendering engine.
$response->headers->set('X-UA-Compatible', 'IE=edge', FALSE);
// Set the Content-language header.
$response->headers->set('Content-language', $this->languageManager->getCurrentLanguage()->getId());
// Prevent browsers from sniffing a response and picking a MIME type
// different from the declared content-type, since that can lead to
// XSS and other vulnerabilities.
// https://www.owasp.org/index.php/List_of_useful_HTTP_headers
$response->headers->set('X-Content-Type-Options', 'nosniff', FALSE);
// Attach globally-declared headers to the response object so that Symfony
// can send them for us correctly.
// @todo Remove this once drupal_process_attached() no longer calls
// _drupal_add_http_header(), which has its own static. Instead,
// _drupal_process_attached() should use
// \Symfony\Component\HttpFoundation\Response->headers->set(), which is
// already documented on the (deprecated) _drupal_process_attached() to
// become the final, intended mechanism.
$headers = drupal_get_http_header();
foreach ($headers as $name => $value) {
// Symfony special-cases the 'Status' header.
if ($name === 'status') {
$response->setStatusCode($value);
}
$response->headers->set($name, $value, FALSE);
}
// Expose the cache contexts and cache tags associated with this page in a
// X-Drupal-Cache-Contexts and X-Drupal-Cache-Tags header respectively.
if ($response instanceof CacheableResponseInterface) {
$response_cacheability = $response->getCacheableMetadata();
$response->headers->set('X-Drupal-Cache-Tags', implode(' ', $response_cacheability->getCacheTags()));
$response->headers->set('X-Drupal-Cache-Contexts', implode(' ', $this->cacheContextsManager->optimizeTokens($response_cacheability->getCacheContexts())));
}
$is_cacheable = $this->requestPolicy->check($request) === RequestPolicyInterface::ALLOW && $this->responsePolicy->check($response, $request) !== ResponsePolicyInterface::DENY;
// Add headers necessary to specify whether the response should be cached by
// proxies and/or the browser.
if ($is_cacheable && $this->config->get('cache.page.max_age') > 0) {
if (!$this->isCacheControlCustomized($response)) {
// Only add the default Cache-Control header if the controller did not
// specify one on the response.
$this->setResponseCacheable($response, $request);
}
} else {
// If either the policy forbids caching or the sites configuration does
// not allow to add a max-age directive, then enforce a Cache-Control
// header declaring the response as not cacheable.
$this->setResponseNotCacheable($response, $request);
}
}
/**
* Sets extra headers on successful responses.
*
* @param Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
* The event to process.
*/
public function onRespond(FilterResponseEvent $event)
{
if ($event->getRequestType() !== HttpKernelInterface::MASTER_REQUEST) {
return;
}
$request = $event->getRequest();
$response = $event->getResponse();
// Set the X-UA-Compatible HTTP header to force IE to use the most recent
// rendering engine or use Chrome's frame rendering engine if available.
$response->headers->set('X-UA-Compatible', 'IE=edge,chrome=1', FALSE);
// Set the Content-language header.
$response->headers->set('Content-language', $this->languageManager->getCurrentLanguage()->getId());
// Attach globally-declared headers to the response object so that Symfony
// can send them for us correctly.
// @todo Remove this once drupal_process_attached() no longer calls
// _drupal_add_http_header(), which has its own static. Instead,
// _drupal_process_attached() should use
// \Symfony\Component\HttpFoundation\Response->headers->set(), which is
// already documented on the (deprecated) _drupal_process_attached() to
// become the final, intended mechanism.
$headers = drupal_get_http_header();
foreach ($headers as $name => $value) {
// Symfony special-cases the 'Status' header.
if ($name === 'status') {
$response->setStatusCode($value);
}
$response->headers->set($name, $value, FALSE);
}
$is_cacheable = $this->requestPolicy->check($request) === RequestPolicyInterface::ALLOW && $this->responsePolicy->check($response, $request) !== ResponsePolicyInterface::DENY;
// Add headers necessary to specify whether the response should be cached by
// proxies and/or the browser.
if ($is_cacheable && $this->config->get('cache.page.max_age') > 0) {
if (!$this->isCacheControlCustomized($response)) {
// Only add the default Cache-Control header if the controller did not
// specify one on the response.
$this->setResponseCacheable($response, $request);
}
} else {
// If either the policy forbids caching or the sites configuration does
// not allow to add a max-age directive, then enforce a Cache-Control
// header declaring the response as not cacheable.
$this->setResponseNotCacheable($response, $request);
}
// Currently it is not possible to cache some types of responses. Therefore
// exclude binary file responses (generated files, e.g. images with image
// styles) and streamed responses (files directly read from the disk).
// see: https://github.com/symfony/symfony/issues/9128#issuecomment-25088678
if ($is_cacheable && $this->config->get('cache.page.use_internal') && !$response instanceof BinaryFileResponse && !$response instanceof StreamedResponse) {
// Store the response in the internal page cache.
drupal_page_set_cache($response, $request);
$response->headers->set('X-Drupal-Cache', 'MISS');
drupal_serve_page_from_cache($response, $request);
}
}
/**
* Fetches a response from the backend and stores it in the cache.
*
* If page_compression is enabled, a gzipped version of the page is stored in
* the cache to avoid compressing the output on each request. The cache entry
* is unzipped in the relatively rare event that the page is requested by a
* client without gzip support.
*
* Page compression requires the PHP zlib extension
* (http://php.net/manual/ref.zlib.php).
*
* @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, $catch);
// Drupal's primary cache invalidation architecture is cache tags: any
// response that varies by a configuration value or data in a content
// entity should have cache tags, to allow for instant cache invalidation
// when that data is updated. However, HTTP does not standardize how to
// encode cache tags in a response. Different CDNs implement their own
// approaches, and configurable reverse proxies (e.g., Varnish) allow for
// custom implementations. To keep Drupal's internal page cache simple, we
// only cache CacheableResponseInterface responses, since those provide a
// defined API for retrieving cache tags. For responses that do not
// implement CacheableResponseInterface, there's no easy way to distinguish
// responses that truly don't depend on any site data from responses that
// contain invalidation information customized to a particular proxy or
// CDN.
// - Drupal modules are encouraged to use CacheableResponseInterface
// responses where possible and to leave the encoding of that information
// into response headers to the corresponding proxy/CDN integration
// modules.
// - Custom applications that wish to provide internal page cache support
// for responses that do not implement CacheableResponseInterface may do
// so by replacing/extending this middleware service or adding another
// one.
if (!$response instanceof CacheableResponseInterface) {
return $response;
}
// Currently it is not possible to cache binary file or streamed responses:
// https://github.com/symfony/symfony/issues/9128#issuecomment-25088678.
// Therefore exclude them, even for subclasses that implement
// CacheableResponseInterface.
if ($response instanceof BinaryFileResponse || $response instanceof StreamedResponse) {
return $response;
}
// Allow policy rules to further restrict which responses to cache.
if ($this->responsePolicy->check($response, $request) === ResponsePolicyInterface::DENY) {
return $response;
}
// The response passes all of the above checks, so cache it.
// - 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.
$tags = $response->getCacheableMetadata()->getCacheTags();
$date = $response->getExpires()->getTimestamp();
$expire = $date > time() ? $date : Cache::PERMANENT;
$this->set($request, $response, $expire, $tags);
// Mark response as a cache miss.
$response->headers->set('X-Drupal-Cache', 'MISS');
return $response;
}
/**
* Stores a response in case of a Dynamic Page Cache miss, if cacheable.
*
* @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
* The event to process.
*/
public function onResponse(FilterResponseEvent $event)
{
$response = $event->getResponse();
// Dynamic Page Cache only works with cacheable responses. It does not work
// with plain Response objects. (Dynamic Page Cache needs to be able to
// access and modify the cacheability metadata associated with the
// response.)
if (!$response instanceof CacheableResponseInterface) {
return;
}
// There's no work left to be done if this is a Dynamic Page Cache hit.
if ($response->headers->get(self::HEADER) === 'HIT') {
return;
}
// There's no work left to be done if this is an uncacheable response.
if (!$this->shouldCacheResponse($response)) {
// The response is uncacheable, mark it as such.
$response->headers->set(self::HEADER, 'UNCACHEABLE');
return;
}
// Don't cache the response if Dynamic Page Cache's request subscriber did
// not fire, because that means it is impossible to have a Dynamic Page
// Cache hit. This can happen when the master request is for example a 403
// or 404, in which case a subrequest is performed by the router. In that
// case, it is the subrequest's response that is cached by Dynamic Page
// Cache, because the routing happens in a request subscriber earlier than
// Dynamic Page Cache's and immediately sets a response, i.e. the one
// returned by the subrequest, and thus causes Dynamic Page Cache's request
// subscriber to not fire for the master request.
// @see \Drupal\Core\Routing\AccessAwareRouter::checkAccess()
// @see \Drupal\Core\EventSubscriber\DefaultExceptionHtmlSubscriber::on403()
$request = $event->getRequest();
if (!isset($this->requestPolicyResults[$request])) {
return;
}
// Don't cache the response if the Dynamic Page Cache request & response
// policies are not met.
// @see onRouteMatch()
if ($this->requestPolicyResults[$request] === RequestPolicyInterface::DENY || $this->responsePolicy->check($response, $request) === ResponsePolicyInterface::DENY) {
return;
}
// Embed the response object in a render array so that RenderCache is able
// to cache it, handling cache redirection for us.
$response_as_render_array = $this->responseToRenderArray($response);
$this->renderCache->set($response_as_render_array, $this->dynamicPageCacheRedirectRenderArray);
// The response was generated, mark the response as a cache miss. The next
// time, it will be a cache hit.
$response->headers->set(self::HEADER, 'MISS');
}
/**
* Fetches a response from the backend and stores it in the cache.
*
* If page_compression is enabled, a gzipped version of the page is stored in
* the cache to avoid compressing the output on each request. The cache entry
* is unzipped in the relatively rare event that the page is requested by a
* client without gzip support.
*
* Page compression requires the PHP zlib extension
* (http://php.net/manual/ref.zlib.php).
*
* @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)
{
$response = $this->httpKernel->handle($request, $type, $catch);
// Currently it is not possible to cache some types of responses. Therefore
// exclude binary file responses (generated files, e.g. images with image
// styles) and streamed responses (files directly read from the disk).
// see: https://github.com/symfony/symfony/issues/9128#issuecomment-25088678
if ($response instanceof BinaryFileResponse || $response instanceof StreamedResponse) {
return $response;
}
if ($this->responsePolicy->check($response, $request) === ResponsePolicyInterface::DENY) {
return $response;
}
// Use the actual timestamp from an Expires header, if available.
$date = $response->getExpires()->getTimestamp();
$expire = $date > time() ? $date : Cache::PERMANENT;
$tags = explode(' ', $response->headers->get('X-Drupal-Cache-Tags'));
$this->set($request, $response, $expire, $tags);
// Mark response as a cache miss.
$response->headers->set('X-Drupal-Cache', 'MISS');
return $response;
}