--- /dev/null
+<?php
+
+namespace Drupal\Core\EventSubscriber;
+
+use Drupal\Component\Datetime\DateTimePlus;
+use Drupal\Core\Cache\CacheableResponseInterface;
+use Drupal\Core\Cache\Context\CacheContextsManager;
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Language\LanguageManagerInterface;
+use Drupal\Core\PageCache\RequestPolicyInterface;
+use Drupal\Core\PageCache\ResponsePolicyInterface;
+use Drupal\Core\Site\Settings;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Response subscriber to handle finished responses.
+ */
+class FinishResponseSubscriber implements EventSubscriberInterface {
+
+ /**
+ * The language manager object for retrieving the correct language code.
+ *
+ * @var \Drupal\Core\Language\LanguageManagerInterface
+ */
+ protected $languageManager;
+
+ /**
+ * A config object for the system performance configuration.
+ *
+ * @var \Drupal\Core\Config\Config
+ */
+ protected $config;
+
+ /**
+ * 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 contexts manager service.
+ *
+ * @var \Drupal\Core\Cache\Context\CacheContextsManager
+ */
+ protected $cacheContexts;
+
+ /**
+ * Whether to send cacheability headers for debugging purposes.
+ *
+ * @var bool
+ */
+ protected $debugCacheabilityHeaders = FALSE;
+
+ /**
+ * Constructs a FinishResponseSubscriber object.
+ *
+ * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
+ * The language manager object for retrieving the correct language code.
+ * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+ * A config factory for retrieving required config objects.
+ * @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 a response.
+ * @param \Drupal\Core\Cache\Context\CacheContextsManager $cache_contexts_manager
+ * The cache contexts manager service.
+ * @param bool $http_response_debug_cacheability_headers
+ * (optional) Whether to send cacheability headers for debugging purposes.
+ */
+ public function __construct(LanguageManagerInterface $language_manager, ConfigFactoryInterface $config_factory, RequestPolicyInterface $request_policy, ResponsePolicyInterface $response_policy, CacheContextsManager $cache_contexts_manager, $http_response_debug_cacheability_headers = FALSE) {
+ $this->languageManager = $language_manager;
+ $this->config = $config_factory->get('system.performance');
+ $this->requestPolicy = $request_policy;
+ $this->responsePolicy = $response_policy;
+ $this->cacheContextsManager = $cache_contexts_manager;
+ $this->debugCacheabilityHeaders = $http_response_debug_cacheability_headers;
+ }
+
+ /**
+ * Sets extra headers on any responses, also subrequest ones.
+ *
+ * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
+ * The event to process.
+ */
+ public function onAllResponds(FilterResponseEvent $event) {
+ $response = $event->getResponse();
+ // Always add the 'http_response' cache tag to be able to invalidate every
+ // response, for example after rebuilding routes.
+ if ($response instanceof CacheableResponseInterface) {
+ $response->getCacheableMetadata()->addCacheTags(['http_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);
+ }
+ }
+
+ /**
+ * Determine whether the given response has a custom Cache-Control header.
+ *
+ * Upon construction, the ResponseHeaderBag is initialized with an empty
+ * Cache-Control header. Consequently it is not possible to check whether the
+ * header was set explicitly by simply checking its presence. Instead, it is
+ * necessary to examine the computed Cache-Control header and compare with
+ * values known to be present only when Cache-Control was never set
+ * explicitly.
+ *
+ * When neither Cache-Control nor any of the ETag, Last-Modified, Expires
+ * headers are set on the response, ::get('Cache-Control') returns the value
+ * 'no-cache'. If any of ETag, Last-Modified or Expires are set but not
+ * Cache-Control, then 'private, must-revalidate' (in exactly this order) is
+ * returned.
+ *
+ * @see \Symfony\Component\HttpFoundation\ResponseHeaderBag::computeCacheControlValue()
+ *
+ * @param \Symfony\Component\HttpFoundation\Response $response
+ *
+ * @return bool
+ * TRUE when Cache-Control header was set explicitly on the given response.
+ */
+ protected function isCacheControlCustomized(Response $response) {
+ $cache_control = $response->headers->get('Cache-Control');
+ return $cache_control != 'no-cache' && $cache_control != 'private, must-revalidate';
+ }
+
+ /**
+ * Add Cache-Control and Expires headers to a response which is not cacheable.
+ *
+ * @param \Symfony\Component\HttpFoundation\Response $response
+ * A response object.
+ * @param \Symfony\Component\HttpFoundation\Request $request
+ * A request object.
+ */
+ protected function setResponseNotCacheable(Response $response, Request $request) {
+ $this->setCacheControlNoCache($response);
+ $this->setExpiresNoCache($response);
+
+ // There is no point in sending along headers necessary for cache
+ // revalidation, if caching by proxies and browsers is denied in the first
+ // place. Therefore remove ETag, Last-Modified and Vary in that case.
+ $response->setEtag(NULL);
+ $response->setLastModified(NULL);
+ $response->setVary(NULL);
+ }
+
+ /**
+ * Add Cache-Control and Expires headers to a cacheable response.
+ *
+ * @param \Symfony\Component\HttpFoundation\Response $response
+ * A response object.
+ * @param \Symfony\Component\HttpFoundation\Request $request
+ * A request object.
+ */
+ protected function setResponseCacheable(Response $response, Request $request) {
+ // HTTP/1.0 proxies do not support the Vary header, so prevent any caching
+ // by sending an Expires date in the past. HTTP/1.1 clients ignore the
+ // Expires header if a Cache-Control: max-age directive is specified (see
+ // RFC 2616, section 14.9.3).
+ if (!$response->headers->has('Expires')) {
+ $this->setExpiresNoCache($response);
+ }
+
+ $max_age = $this->config->get('cache.page.max_age');
+ $response->headers->set('Cache-Control', 'public, max-age=' . $max_age);
+
+ // In order to support HTTP cache-revalidation, ensure that there is a
+ // Last-Modified and an ETag header on the response.
+ if (!$response->headers->has('Last-Modified')) {
+ $timestamp = REQUEST_TIME;
+ $response->setLastModified(new \DateTime(gmdate(DateTimePlus::RFC7231, REQUEST_TIME)));
+ }
+ else {
+ $timestamp = $response->getLastModified()->getTimestamp();
+ }
+ $response->setEtag($timestamp);
+
+ // Allow HTTP proxies to cache pages for anonymous users without a session
+ // cookie. The Vary header is used to indicates the set of request-header
+ // fields that fully determines whether a cache is permitted to use the
+ // response to reply to a subsequent request for a given URL without
+ // revalidation.
+ if (!$response->hasVary() && !Settings::get('omit_vary_cookie')) {
+ $response->setVary('Cookie', FALSE);
+ }
+ }
+
+ /**
+ * Disable caching in the browser and for HTTP/1.1 proxies and clients.
+ *
+ * @param \Symfony\Component\HttpFoundation\Response $response
+ * A response object.
+ */
+ protected function setCacheControlNoCache(Response $response) {
+ $response->headers->set('Cache-Control', 'no-cache, must-revalidate');
+ }
+
+ /**
+ * Disable caching in ancient browsers and for HTTP/1.0 proxies and clients.
+ *
+ * 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).
+ *
+ * @param \Symfony\Component\HttpFoundation\Response $response
+ * A response object.
+ */
+ protected function setExpiresNoCache(Response $response) {
+ $response->setExpires(\DateTime::createFromFormat('j-M-Y H:i:s T', '19-Nov-1978 05:00:00 UTC'));
+ }
+
+ /**
+ * Registers the methods in this class that should be listeners.
+ *
+ * @return array
+ * An array of event listener definitions.
+ */
+ public static function getSubscribedEvents() {
+ $events[KernelEvents::RESPONSE][] = ['onRespond'];
+ // There is no specific reason for choosing 16 beside it should be executed
+ // before ::onRespond().
+ $events[KernelEvents::RESPONSE][] = ['onAllResponds', 16];
+ return $events;
+ }
+
+}
projects / yaffs-website / blobdiff