Add support for outside listeners

[inxilpro]

This lets you register outside listeners for events. Say you have an analytics process, or some secondary reporting functionality that you want to add. Sometimes it doesn't make sense for those to exist on the event itself. Now you can do something like:

class AnalyticsProjector
{
  // This will implicitly run when `handle` is called
  public function onDownload(ProductDownloaded $event)
  {
    Analytics::incrementDownloads();
  }

  // Or you can use attributes to be explicit and set phases
  #[Listen(ProductDownloaded::class)]
  #[Listen(ProductUpdated::class)]
  #[Listen(ProductDiscontinued::class)]
  #[On(Phase::Fired)]
  public function genericListener($event)
  {
    // will get called during the "fired" phase when any of those events fire
  }
}

Then you just register with:

Verbs::listen(AnalyticsProjector::class);

[inxilpro]

Ugh. I accidentally ran pint on everything. I'll revert before marking as ready.

[inmanturbo]

What is the status on this? Is it currently possible to listen or subscribe to verb events outside of the event definition itself?

In our case the event itself will be inaccessible to the developer writing projections in some cases, as it will be in another code base (composer package) handled by another team. In other words for some parts of the system we will have one development team publishing events and another team subscribing to them.

[inmanturbo]

As a workaround I'll be testing a POC using circular dependency. I.E.:

// after apply()

public function handle()
{
    $listeners = app(CustomerHandlers::class)->getListeners();

    foreach ($listeners as $listener) {
        $listener->handle($this);
    }
}

// meanwhile, somewhere in a whole 'nother code base ...

class SubscriptionHandler implements CustomerHandler
{
    public function handle(Event $event): mixed
    {
        return match(get_class($event))  {
            CustomerBeganTrial::class => Subscription::create([
                'customer_id' => $event->customer_id,
                'expires_at' => now()->addDays(30),
            ]),
            default => null,
        };
    }
}