— this contains BigPipe
* placeholders for the personalized parts of the page. Hence this sends the
* non-personalized parts of the page. Let's call it The Skeleton.
* 2. N chunks: a ';
/**
* The BigPipe placeholder replacements stop signal.
*
* @var string
*/
const STOP_SIGNAL = '';
/**
* The renderer.
*
* @var \Drupal\Core\Render\RendererInterface
*/
protected $renderer;
/**
* The session.
*
* @var \Symfony\Component\HttpFoundation\Session\SessionInterface
*/
protected $session;
/**
* The request stack.
*
* @var \Symfony\Component\HttpFoundation\RequestStack
*/
protected $requestStack;
/**
* The HTTP kernel.
*
* @var \Symfony\Component\HttpKernel\HttpKernelInterface
*/
protected $httpKernel;
/**
* The event dispatcher.
*
* @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
*/
protected $eventDispatcher;
/**
* The config factory.
*
* @var \Drupal\Core\Config\ConfigFactoryInterface
*/
protected $configFactory;
/**
* Constructs a new BigPipe class.
*
* @param \Drupal\Core\Render\RendererInterface $renderer
* The renderer.
* @param \Symfony\Component\HttpFoundation\Session\SessionInterface $session
* The session.
* @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
* The request stack.
* @param \Symfony\Component\HttpKernel\HttpKernelInterface $http_kernel
* The HTTP kernel.
* @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
* The event dispatcher.
* @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
* The config factory.
*/
public function __construct(RendererInterface $renderer, SessionInterface $session, RequestStack $request_stack, HttpKernelInterface $http_kernel, EventDispatcherInterface $event_dispatcher, ConfigFactoryInterface $config_factory) {
$this->renderer = $renderer;
$this->session = $session;
$this->requestStack = $request_stack;
$this->httpKernel = $http_kernel;
$this->eventDispatcher = $event_dispatcher;
$this->configFactory = $config_factory;
}
/**
* Performs tasks before sending content (and rendering placeholders).
*/
protected function performPreSendTasks() {
// The content in the placeholders may depend on the session, and by the
// time the response is sent (see index.php), the session is already
// closed. Reopen it for the duration that we are rendering placeholders.
$this->session->start();
}
/**
* Performs tasks after sending content (and rendering placeholders).
*/
protected function performPostSendTasks() {
// Close the session again.
$this->session->save();
}
/**
* Sends a chunk.
*
* @param string|\Drupal\Core\Render\HtmlResponse $chunk
* The string or response to append. String if there's no cacheability
* metadata or attachments to merge.
*/
protected function sendChunk($chunk) {
assert(is_string($chunk) || $chunk instanceof HtmlResponse);
if ($chunk instanceof HtmlResponse) {
print $chunk->getContent();
}
else {
print $chunk;
}
flush();
}
/**
* Sends an HTML response in chunks using the BigPipe technique.
*
* @param \Drupal\big_pipe\Render\BigPipeResponse $response
* The BigPipe response to send.
*
* @internal
* This method should only be invoked by
* \Drupal\big_pipe\Render\BigPipeResponse, which is itself an internal
* class.
*/
public function sendContent(BigPipeResponse $response) {
$content = $response->getContent();
$attachments = $response->getAttachments();
// First, gather the BigPipe placeholders that must be replaced.
$placeholders = isset($attachments['big_pipe_placeholders']) ? $attachments['big_pipe_placeholders'] : [];
$nojs_placeholders = isset($attachments['big_pipe_nojs_placeholders']) ? $attachments['big_pipe_nojs_placeholders'] : [];
// BigPipe sends responses using "Transfer-Encoding: chunked". To avoid
// sending already-sent assets, it is necessary to track cumulative assets
// from all previously rendered/sent chunks.
// @see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.41
$cumulative_assets = AttachedAssets::createFromRenderArray(['#attached' => $attachments]);
$cumulative_assets->setAlreadyLoadedLibraries($attachments['library']);
$this->performPreSendTasks();
// Find the closing tag and get the strings before and after. But be
// careful to use the latest occurrence of the string "", to ensure
// that strings in inline JavaScript or CDATA sections aren't used instead.
$parts = explode('', $content);
$post_body = array_pop($parts);
$pre_body = implode('', $parts);
$this->sendPreBody($pre_body, $nojs_placeholders, $cumulative_assets);
$this->sendPlaceholders($placeholders, $this->getPlaceholderOrder($pre_body, $placeholders), $cumulative_assets);
$this->sendPostBody($post_body);
$this->performPostSendTasks();
}
/**
* Sends everything until just before .
*
* @param string $pre_body
* The HTML response's content until the closing tag.
* @param array $no_js_placeholders
* The no-JS BigPipe placeholders.
* @param \Drupal\Core\Asset\AttachedAssetsInterface $cumulative_assets
* The cumulative assets sent so far; to be updated while rendering no-JS
* BigPipe placeholders.
*/
protected function sendPreBody($pre_body, array $no_js_placeholders, AttachedAssetsInterface $cumulative_assets) {
// If there are no no-JS BigPipe placeholders, we can send the pre-
// part of the page immediately.
if (empty($no_js_placeholders)) {
$this->sendChunk($pre_body);
return;
}
// Extract the scripts_bottom markup: the no-JS BigPipe placeholders that we
// will render may attach additional asset libraries, and if so, it will be
// necessary to re-render scripts_bottom.
list($pre_scripts_bottom, $scripts_bottom, $post_scripts_bottom) = explode('