PSR-14 events and signals¶

Target group: Developers

Table of Contents

Introduction
- PSR-14 events
- Signal/slots
Register additional properties for a type
- PSR-14 event (for TYPO3 v10+)
- Signal/slot (for TYPO3 v9/v10/v11)
Activate or deactivate embedding of markup on pages
- PSR-14 event (for TYPO3 v10+)
- Signal/slot (for TYPO3 v9/v10/v11)

Introduction ¶

There are currently two ways to enhance the functionality in the schema extension. Both variants receive an event that provides methods for retrieving and setting dedicated properties. The class for a slot can be easily reused for later use as a PSR-14 event listener during migration.

Attention

In TYPO3 v10/v11 you can use signal/slots and PSR-14 events. If you use both, the PSR-14 events are called first in this extension, and the signal/slots operate on the modified event from the PSR-14 events.

PSR-14 events ¶

The standardised way, which is available since TYPO3 v10. If you are using TYPO3 v10 or above, use event listeners to be future-proof.

Signal/slots ¶

This is the only way in TYPO3 v9 and deprecated in TYPO3 v10.

Register additional properties for a type ¶

Sometimes it can be necessary to use properties which are not standardised or pending, or to add property annotations. Therefore an event is available which can be used in a slot (TYPO3 v9/v10/v11) and a PSR-14 event listener (TYPO3 v10+).

These additional properties are not only available in the API but also as arguments in the view helpers.

The event Brotkrueml\Schema\Event\RegisterAdditionalTypePropertiesEvent provides the following methods:

getType(): string¶

Returns the class name of the type. You can use this to add a property only to one type.

getAdditionalProperties(): array¶

Retrieve the already defined additionalProperties for this type, e.g. by other slots/event listeners.

registerAdditionalProperty(string $propertyName): void¶

This method registers an additional property for one or more types.

PSR-14 event (for TYPO3 v10+)¶

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\RegisterAdditionalTypePropertiesEvent;
use Brotkrueml\Schema\Model\Type\Person;

final class AdditionalPropertiesForPerson
{
   public function __invoke(RegisterAdditionalTypePropertiesEvent $event): void
   {
      if ($event->getType() === Person::class) {
         $event->registerAdditionalProperty('gender');
         $event->registerAdditionalProperty('jobTitle');
      }
   }
}

The method __invoke() implements the logic for registering additional properties for one or more types. It receives the RegisterAdditionalTypePropertiesEvent. You can register as many properties as you want.

Register your event listener in Configuration/Services.yaml

services:
   YourVendor\YourExtension\EventListener\AdditionalPropertiesForPerson:
      tags:
         - name: event.listener
           identifier: 'myAdditionalPropertiesForPerson'
           event: Brotkrueml\Schema\Event\RegisterAdditionalTypePropertiesEvent

Signal/slot (for TYPO3 v9/v10/v11)¶

Note

If you use TYPO3 v10 or above 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.

Tip

Place the slot in the folder EventListener (like in the example below). So you are prepared for PSR-14 events in TYPO3 v10.

Create the slot

<?php
declare(strict_types=1);

namespace YourVendor\YourExtension\EventListener;

use Brotkrueml\Schema\Event\RegisterAdditionalTypePropertiesEvent;
use Brotkrueml\Schema\Model\Type\Person;

final class AdditionalPropertiesForPerson
{
   public function __invoke(RegisterAdditionalTypePropertiesEvent $event): void
   {
      if ($event->getType() === Person::class) {
         $event->registerAdditionalProperty('gender');
         $event->registerAdditionalProperty('jobTitle');
      }
   }
}

In this example, the method __invoke() implements the logic for registering the additional properties. It receives the RegisterAdditionalTypePropertiesEvent. Assign a new state with the registerAdditionalProperty() method. If you compare this slot with the event listener above, the only change is the namespace. This makes migration to the PSR-14 events much easier.

Register the slot in ext_localconf.php

$signalSlotDispatcher = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(
   TYPO3\CMS\Extbase\SignalSlot\Dispatcher::class
);
$signalSlotDispatcher->connect(
   \Brotkrueml\Schema\Core\Model\AbstractType::class,
   'registerAdditionalTypeProperties',
   \YourVendor\YourExtension\EventListener\AdditionalPropertiesForPerson::class,
   '__invoke'
);

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

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/v11 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.

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+.

Note

It can be necessary to define an order for these event listeners. Use before or after for this when configuring the event listener in the Configuration/Services.yaml file. Also note that this extension ships an event listener for deactivating the embedding of structured data dependent on the noindex field of the seo system extension.

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: 'myLogicForEmbeddingMarkup'
           event: Brotkrueml\Schema\Event\ShouldEmbedMarkupEvent

Signal/slot (for TYPO3 v9/v10/v11)¶

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 or above 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.

Tip

Place the slot in the folder EventListener (like in the example below). So you are prepared for PSR-14 events in TYPO3 v10.

Create the Slot

<?php
declare(strict_types=1);

namespace YourVendor\YourExtension\EventListener;

use Brotkrueml\Schema\Event\ShouldEmbedMarkupEvent;

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

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

In this example, the method __invoke() implements the logic for the embedding of the markup. It receives the ShouldEmbedMarkupEvent. Assign a new state with the setEmbedMarkup() method. If you compare this slot with the event listener above, the only change is the namespace. This makes migration to the PSR-14 events much easier.

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\EventListener\EmbedMarkupDependentOnPageUid::class,
   '__invoke'
);

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