PSR-14 Events and Signals¶

Target group: Developers

Activate or Deactivate Embedding of Markup on Pages¶

As default, markup is not embedded on pages which should not be indexed by search engines (if the seo system extension is used). But sometimes it’s intentional to add markup on such a page, e.g. you declared a detail page as noindex in the page properties, but the plugin on that page changes it to index.

For TYPO3 v9/v10 you can use a signal/slot, for TYPO3 v10+ is also a PSR-14 event available to change the default behaviour.

Both versions receive the Brotkrueml\Schema\Event\ShouldEmbedMarkupEvent with the following methods:

->getPage(): array

Get the current page fields.

->getEmbedMarkup(): bool

Gets the current status: true if the markup should be embedded, false if not.

->setEmbedMarkup(bool $embedMarkup): void

Sets the status: true if the markups should be embedded, false if not.

Attention

In TYPO3 v10 you can use signal/slots and PSR-14 events. If you use both, the PSR-14 events are called first, and the signal/slots operate on the modified event from the PSR-14 events.

PSR-14 Event (for TYPO3 v10+)¶

With the PSR-14 event Brotkrueml\Schema\Event\ShouldEmbedMarkupEvent you can activate or deactivate the embedding of markup on a specific page.

Note

This is the preferred way for TYPO3 v10+.

Example¶

Create the Event Listener

<?php
declare(strict_types=1);

namespace YourVender\YourExtension\EventListener;

use Brotkrueml\Schema\Event\ShouldEmbedMarkupEvent;

final class EmbedMarkupDependentOnPageUid
{
   public function __invoke(ShouldEmbedMarkupEvent $event): void
   {
      $page = $event->getPage();

      if ($page['uid'] === 42) {
         $event->setEmbedMarkup(true);
      }
   }
}

The method __invoke() implements the logic for changing the embedding of the markup. It receives the ShouldEmbedMarkupEvent. Assign a new state with the setEmbedMarkup() method.

Register your event listener in Configuration/Services.yaml

services:
   YourVendor\YourExtension\EventListener\EmbedMarkupDependentOnPageUid:
      tags:
         - name: event.listener
           identifier: 'ext-schema/shouldEmbedMarkup'
           event: Brotkrueml\Schema\Event\ShouldEmbedMarkupEvent

Signal/Slot (for TYPO3 v9/v10)¶

The signal shouldEmbedMarkup of the Brotkrueml\Schema\Hooks\PageRenderer\SchemaMarkupInjection class enables you to modify the embedding of the markup on a page.

Note

If you use TYPO3 v10 you should use the PSR-14 event above. The signal/slot will be deleted when the compatibility of this extension for TYPO3 v9 is removed in later versions.

Example¶

We use the same example as for the PSR-14 event.

Create the Slot

<?php
declare(strict_types=1);

namespace YourVendor\YourExtension\Slot;

use Brotkrueml\Schema\Event\ShouldEmbedMarkupEvent;

class EmbedMarkupDependentOnPageUid
{
   public function changeEmbedMarkup(ShouldEmbedMarkupEvent $event): void
   {
      $page = $event->getPage();

      if ($page['uid'] === 42) {
         $event->setEmbedMarkup(true);
      }
   }
}

In this example, the method changeEmbedMarkup() implements the logic for the embedding of the markup. It receives the ShouldEmbedMarkupEvent. Assign a new state with the setEmbedMarkup() method.

Register the Slot in ext_localconf.php

$signalSlotDispatcher = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(
   TYPO3\CMS\Extbase\SignalSlot\Dispatcher::class
);
$signalSlotDispatcher->connect(
   \Brotkrueml\Schema\Hooks\PageRenderer\SchemaMarkupInjection::class,
   'shouldEmbedMarkup',
   \YourVendor\YourExtension\Slot\EmbedMarkupDependentOnPageUid::class,
   'changeEmbedMarkup'
);

The third argument of the connect() method is your slot class and the forth argument the method name of that class.