Feature: Change the partner list and map by event 

Description 

\FGTCLB\AcademicPartners\Event\ModifyPartnerDemandEvent and \FGTCLB\AcademicPartners\Event\ModifyPartnerListEvent are PSR-14 events dispatched by both the partner list and the partner map.

The demand event fires after the demand has been built from the content element settings and the request and before the partners are queried; the demand a listener hands back is the one that is queried and assigned to the view. The list event fires after the query and before the view variables are assigned; a listener replaces the partners, replaces the applicable categories, or assigns further view variables.

Both carry \FGTCLB\AcademicBase\Domain\Model\Dto\PluginControllerActionContextInterface , so a listener knows the request, the site, the content element, its settings and whether the list or the map is rendering. Each event is described on a page of its own, see ModifyPartnerDemandEvent and ModifyPartnerListEvent.

<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\EventListener;

use FGTCLB\AcademicPartners\Event\ModifyPartnerDemandEvent;
use TYPO3\CMS\Core\Attribute\AsEventListener;

final class RestrictPartnersToOneFolder
{
    #[AsEventListener(identifier: 'my-extension/restrict-partners-to-one-folder')]
    public function __invoke(ModifyPartnerDemandEvent $event): void
    {
        // The pages the partner records sit *on*: `setPages()` becomes
        // `pid IN (...)`, so this is one storage folder and not a page tree.
        $event->getDemand()->setPages([42]);
    }
}

Impact 

Nothing changes in an installation that has no listener. A project that subclasses PartnerController to adjust the demand, the result or the view variables listens instead, and drops the subclass and the plugin re-registration that goes with it. The controller is final in 3.0, so the subclass no longer loads, see Breaking: The partner controller is final.

Two details are worth knowing. The map restricts the demand to partners that can be drawn after the demand event, because a partner without coordinates would be drawn at 0/0 rather than left out, so a listener cannot bring those onto the map. And the applicable categories are computed once, before the list event, and not recomputed afterwards - a listener that replaces the partners and wants the filter to match them sets the categories as well.