protected PageCache::lookup(Request $request, $type = self::MASTER_REQUEST, $catch = TRUE)
Retrieves a response from the cache or fetches it from the backend.
@returns \Symfony\Component\HttpFoundation\Response $response A response object.
Parameters
\Symfony\Component\HttpFoundation\Request $request: A request object.
int $type: The type of the request (one of HttpKernelInterface::MASTER_REQUEST or HttpKernelInterface::SUB_REQUEST)
bool $catch: Whether to catch exceptions or not
File
- core/modules/page_cache/src/StackMiddleware/PageCache.php, line 116
Class
- PageCache
- Executes the page caching before the main kernel takes over the request.
Namespace
Drupal\page_cache\StackMiddleware
Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 | 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(); } // Negotiate whether to use compression. if (extension_loaded('zlib') && $response->headers->get('Content-Encoding') === 'gzip') { if (strpos($request->headers->get('Accept-Encoding'), 'gzip') !== FALSE) { // The response content is already gzip'ed, so make sure // zlib.output_compression does not compress it once more. ini_set('zlib.output_compression', '0'); } else { // The client does not support compression. Decompress the content and // remove the Content-Encoding header. $content = $response->getContent(); $content = gzinflate(substr(substr($content, 10), 0, -8)); $response->setContent($content); $response->headers->remove('Content-Encoding'); } } // Perform HTTP revalidation. // @todo Use Response::isNotModified() as $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 && $if_none_match == $response->getEtag() // etag must match && $if_modified_since == $last_modified->getTimestamp()) { // if-modified-since must match $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, array('content-location', 'expires', 'cache-control', 'vary'))) { $response->headers->remove($name); } } } } return $response;} |
Please login to continue.