Creating Custom Event Types

Setup the StandardEventFactory to customize the creation process for specific Event types. Labrador async-event recommends creating semantic types to describe your application and has easy ways to facilitate doing so baked into this library.

It is highly recommended you construct all Events with the StandardEventFactory. It is a robust, tested implementation that is flexible enough to support custom instantiation when it is necessary. If you do not provide custom Event construction for emitted events the StandardEvent object will be used.

In our examples we'll use the namespace Acme\Events; this should be replaced with the appropriate top-level namespace for your application.

Step 1. Create your new Event class

<?php declare(strict_types = 1);

namespace Acme\Events;

use Acme\Model\FooModel;
use Cspray\Labrador\AsyncEvent\StandardEvent;

class FooEvent extends StandardEvent {

    public function __construct(FooModel $fooModel) {
        parent::__construct('foo', $fooModel);

Step 2. Register a new factory for the event

The StandardEventFactory::register() method allows you to override how Events are constructed. In our example we'll want to handle passing the correct attributes to our custom Event.

<?php declare(strict_types = 1);

namespace Acme\Events;

use Acme\Model\FooModel;
use Cspray\Labrador\AsyncEvent\StandardEventFactory;

$eventFactory = new StandardEventFactory();
$eventFactory->register('foo', function(FooModel $fooModel) {
    return new FooEvent($fooModel);

Now whenever the 'foo' event is emitted and the StandardEventFactory constructs an Event your factory callable will be invoked instead of the normal StandardEventFactory. It is important to note that the factory callable should match the method signature below. It is possible to make the target type parameter should be made more explicit if you know what type of target to expect.


use Cspray\Labrador\AsyncEvent\Event;

$factoryCallable = function(object $target, array $eventData, ...$createArgs) : Event {};

The StandardEventFactory::create() method allows passing an arbitrary number of arguments after $eventData that will be passed to any custom factory callables. If you do not have a custom factory registered for the event additional arguments after $eventData are ignored.