Feature: #104832 - PSR-14 Event to alter the results of PageTreeRepository

Description

Until TYPO3 v9, it was possible to alter the rendering of one of TYPO3's superpowers — the page tree in the TYPO3 Backend User Interface.

This was done via a "Hook", but was removed due to the migration towards an SVG-based tree rendering.

As the Page Tree Rendering has evolved, and the hook system has been replaced in favor of PSR-14 Events, a new event \TYPO3\CMS\Backend\Tree\Repository\AfterRawPageRowPreparedEvent has been introduced.

Example

The event listener class, using the PHP attribute #[AsEventListener] for registration, will remove any children for displaying for the page with the UID 123:

use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Backend\Tree\Repository\AfterRawPageRowPreparedEvent;

final class MyEventListener
{
    #[AsEventListener]
    public function __invoke(AfterRawPageRowPreparedEvent $event): void
    {
        $rawPage = $event->getRawPage();
        if ((int)$rawPage['uid'] === 123) {
            $rawPage['_children'] = [];
            $event->setRawPage($rawPage);
        }
    }
}

Impact

Using the new PSR-14 event, it is now possible to modify the populated page properties or its children records.