Events and Listeners

Learn more about events and listeners in our developer documentation.

Plugins can create listeners to subscribe to events triggered by the core application. Events are new in 3.4. Only a small number of events are used now. In the future, we plan to use them more.

Find all of the events in the classes/observers/events and lib/pkp/classes/observers/events directories.

Send Files to Production Pipeline #

A plugin may want to send copyedited files to a third-party service when a submission is sent to production. First, create the listener.

namespace APP\plugins\generic\example;

use APP\facades\Repo;
use Illuminate\Events\Dispatcher;
use PKP\decision\types\SendToProduction;
use PKP\observers\events\DecisionAdded;
use PKP\submissionFile\SubmissionFile;

class ExampleListener
{
    public function subscribe(Dispatcher $events): void
    {
        $events->listen(
            DecisionAdded::class,
            ExampleListener::class
        );
    }

    public function handle(DecisionAdded $event)
    {
        if (!is_a($event->decisionType, SendToProduction::class)) {
            return;
        }

        $submissionFiles = Repo::submissionFile()
            ->getCollector()
            ->filterBySubmissionIds([$event->submission->getId()])
            ->filterByFileStages([
                SubmissionFile::SUBMISSION_FILE_PRODUCTION_READY,
            ])
            ->getMany();

        if ($submissionFiles->count()) {
            // Send files to third-party service.
        }
    }
}

Then subscribe the listener to the event in the plugin’s registration method.

namespace APP\plugins\generic\example;

use Illuminate\Support\Facades\Event;
use PKP\observers\events\DecisionAdded;
use PKP\plugins\GenericPlugin;

class ExamplePlugin extends GenericPlugin
{
    public function register($category, $path, $mainContextId = NULL)
    {
        $success = parent::register($category, $path);

        if ($success && $this->getEnabled()) {
            Event::subscribe(new ExampleListener());
        }

        return $success;
    }
}

View more examples.

Events and Listeners

Send Files to Production Pipeline #

Summary