/**
* Returns the libraries that need to be loaded.
*
* For example, with core/a depending on core/c and core/b on core/d:
* @code
* $assets = new AttachedAssets();
* $assets->setLibraries(['core/a', 'core/b', 'core/c']);
* $assets->setAlreadyLoadedLibraries(['core/c']);
* $resolver->getLibrariesToLoad($assets) === ['core/a', 'core/b', 'core/d']
* @endcode
*
* @param \Drupal\Core\Asset\AttachedAssetsInterface $assets
* The assets attached to the current response.
*
* @return string[]
* A list of libraries and their dependencies, in the order they should be
* loaded, excluding any libraries that have already been loaded.
*/
protected function getLibrariesToLoad(AttachedAssetsInterface $assets)
{
return array_diff($this->libraryDependencyResolver->getLibrariesWithDependencies($assets->getLibraries()), $this->libraryDependencyResolver->getLibrariesWithDependencies($assets->getAlreadyLoadedLibraries()));
}
/**
* Sends BigPipe placeholders' replacements as embedded AJAX responses.
*
* @param array $placeholders
* Associative array; the BigPipe placeholders. Keys are the BigPipe
* placeholder IDs.
* @param array $placeholder_order
* Indexed array; the order in which the BigPipe placeholders must be sent.
* Values are the BigPipe placeholder IDs. (These values correspond to keys
* in $placeholders.)
* @param \Drupal\Core\Asset\AttachedAssetsInterface $cumulative_assets
* The cumulative assets sent so far; to be updated while rendering BigPipe
* placeholders.
*
* @throws \Exception
* If an exception is thrown during the rendering of a placeholder, it is
* caught to allow the other placeholders to still be replaced. But when
* error logging is configured to be verbose, the exception is rethrown to
* simplify debugging.
*/
protected function sendPlaceholders(array $placeholders, array $placeholder_order, AttachedAssetsInterface $cumulative_assets)
{
// Return early if there are no BigPipe placeholders to send.
if (empty($placeholders)) {
return;
}
// Send the start signal.
print "\n";
print static::START_SIGNAL;
print "\n";
flush();
// A BigPipe response consists of a HTML response plus multiple embedded
// AJAX responses. To process the attachments of those AJAX responses, we
// need a fake request that is identical to the master request, but with
// one change: it must have the right Accept header, otherwise the work-
// around for a bug in IE9 will cause not JSON, but <textarea>-wrapped JSON
// to be returned.
// @see \Drupal\Core\EventSubscriber\AjaxResponseSubscriber::onResponse()
$fake_request = $this->requestStack->getMasterRequest()->duplicate();
$fake_request->headers->set('Accept', 'application/vnd.drupal-ajax');
foreach ($placeholder_order as $placeholder_id) {
if (!isset($placeholders[$placeholder_id])) {
continue;
}
// Render the placeholder.
$placeholder_render_array = $placeholders[$placeholder_id];
try {
$elements = $this->renderPlaceholder($placeholder_id, $placeholder_render_array);
} catch (\Exception $e) {
if (\Drupal::config('system.logging')->get('error_level') === ERROR_REPORTING_DISPLAY_VERBOSE) {
throw $e;
} else {
trigger_error($e, E_USER_ERROR);
continue;
}
}
// Create a new AjaxResponse.
$ajax_response = new AjaxResponse();
// JavaScript's querySelector automatically decodes HTML entities in
// attributes, so we must decode the entities of the current BigPipe
// placeholder ID (which has HTML entities encoded since we use it to find
// the placeholders).
$big_pipe_js_placeholder_id = Html::decodeEntities($placeholder_id);
$ajax_response->addCommand(new ReplaceCommand(sprintf('[data-big-pipe-placeholder-id="%s"]', $big_pipe_js_placeholder_id), $elements['#markup']));
$ajax_response->setAttachments($elements['#attached']);
// Push a fake request with the asset libraries loaded so far and dispatch
// KernelEvents::RESPONSE event. This results in the attachments for the
// AJAX response being processed by AjaxResponseAttachmentsProcessor and
// hence:
// - the necessary AJAX commands to load the necessary missing asset
// libraries and updated AJAX page state are added to the AJAX response
// - the attachments associated with the response are finalized, which
// allows us to track the total set of asset libraries sent in the
// initial HTML response plus all embedded AJAX responses sent so far.
$fake_request->request->set('ajax_page_state', ['libraries' => implode(',', $cumulative_assets->getAlreadyLoadedLibraries())] + $cumulative_assets->getSettings()['ajaxPageState']);
try {
$ajax_response = $this->filterEmbeddedResponse($fake_request, $ajax_response);
} catch (\Exception $e) {
if (\Drupal::config('system.logging')->get('error_level') === ERROR_REPORTING_DISPLAY_VERBOSE) {
throw $e;
} else {
trigger_error($e, E_USER_ERROR);
continue;
}
}
// Send this embedded AJAX response.
$json = $ajax_response->getContent();
$output = <<<EOF
<script type="application/vnd.drupal-ajax" data-big-pipe-replacement-for-placeholder-with-id="{$placeholder_id}">
{$json}
</script>
EOF;
print $output;
flush();
// Another placeholder was rendered and sent, track the set of asset
// libraries sent so far. Any new settings are already sent; we don't need
// to track those.
if (isset($ajax_response->getAttachments()['drupalSettings']['ajaxPageState']['libraries'])) {
$cumulative_assets->setAlreadyLoadedLibraries(explode(',', $ajax_response->getAttachments()['drupalSettings']['ajaxPageState']['libraries']));
}
}
// Send the stop signal.
print "\n";
print static::STOP_SIGNAL;
print "\n";
flush();
}
/**
* Sends BigPipe placeholders' replacements as embedded AJAX responses.
*
* @param array $placeholders
* Associative array; the BigPipe placeholders. Keys are the BigPipe
* selectors.
* @param array $placeholder_order
* Indexed array; the order in which the BigPipe placeholders must be sent.
* Values are the BigPipe selectors. (These values correspond to keys in
* $placeholders.)
* @param \Drupal\Core\Asset\AttachedAssetsInterface $cumulative_assets
* The cumulative assets sent so far; to be updated while rendering BigPipe
* placeholders.
*/
protected function sendPlaceholders(array $placeholders, array $placeholder_order, AttachedAssetsInterface $cumulative_assets)
{
// Return early if there are no BigPipe placeholders to send.
if (empty($placeholders)) {
return;
}
// Send a container and the start signal.
print "\n";
print '<script type="application/json" data-big-pipe-event="start"></script>' . "\n";
flush();
// A BigPipe response consists of a HTML response plus multiple embedded
// AJAX responses. To process the attachments of those AJAX responses, we
// need a fake request that is identical to the master request, but with
// one change: it must have the right Accept header, otherwise the work-
// around for a bug in IE9 will cause not JSON, but <textarea>-wrapped JSON
// to be returned.
// @see \Drupal\Core\EventSubscriber\AjaxResponseSubscriber::onResponse()
$fake_request = $this->requestStack->getMasterRequest()->duplicate();
$fake_request->headers->set('Accept', 'application/json');
foreach ($placeholder_order as $placeholder) {
if (!isset($placeholders[$placeholder])) {
continue;
}
// Render the placeholder.
$placeholder_render_array = $placeholders[$placeholder];
$elements = $this->renderPlaceholder($placeholder, $placeholder_render_array);
// Create a new AjaxResponse.
$ajax_response = new AjaxResponse();
// JavaScript's querySelector automatically decodes HTML entities in
// attributes, so we must decode the entities of the current BigPipe
// placeholder (which has HTML entities encoded since we use it to find
// the placeholders).
$big_pipe_js_selector = Html::decodeEntities($placeholder);
$ajax_response->addCommand(new ReplaceCommand(sprintf('[data-big-pipe-selector="%s"]', $big_pipe_js_selector), $elements['#markup']));
$ajax_response->setAttachments($elements['#attached']);
// Push a fake request with the asset libraries loaded so far and dispatch
// KernelEvents::RESPONSE event. This results in the attachments for the
// AJAX response being processed by AjaxResponseAttachmentsProcessor and
// hence:
// - the necessary AJAX commands to load the necessary missing asset
// libraries and updated AJAX page state are added to the AJAX response
// - the attachments associated with the response are finalized, which
// allows us to track the total set of asset libraries sent in the
// initial HTML response plus all embedded AJAX responses sent so far.
$fake_request->request->set('ajax_page_state', ['libraries' => implode(',', $cumulative_assets->getAlreadyLoadedLibraries())] + $cumulative_assets->getSettings()['ajaxPageState']);
$this->requestStack->push($fake_request);
$event = new FilterResponseEvent($this->httpKernel, $fake_request, HttpKernelInterface::SUB_REQUEST, $ajax_response);
$this->eventDispatcher->dispatch(KernelEvents::RESPONSE, $event);
$ajax_response = $event->getResponse();
$this->requestStack->pop();
// Send this embedded AJAX response.
$json = $ajax_response->getContent();
$output = <<<EOF
<script type="application/json" data-big-pipe-placeholder="{$placeholder}" data-drupal-ajax-processor="big_pipe">
{$json}
</script>
EOF;
print $output;
flush();
// Another placeholder was rendered and sent, track the set of asset
// libraries sent so far. Any new settings are already sent; we don't need
// to track those.
if (isset($ajax_response->getAttachments()['drupalSettings']['ajaxPageState']['libraries'])) {
$cumulative_assets->setAlreadyLoadedLibraries(explode(',', $ajax_response->getAttachments()['drupalSettings']['ajaxPageState']['libraries']));
}
}
// Send the stop signal.
print '<script type="application/json" data-big-pipe-event="stop"></script>' . "\n";
flush();
}
