Add subscribe method to event extender

src/Extend/Event.php

@@ -16,6 +16,7 @@
 class Event implements ExtenderInterface
 {
     private $listeners = [];
+    private $subscribers = [];
 
     /**
      * Add a listener to a domain event dispatched by flarum or a flarum extension.
@@ -34,12 +35,32 @@ public function listen(string $event, $listener)
         return $this;
     }
 
+    /**
+     * Add a subscriber for a set of domain events dispatched by flarum or a flarum extension.
+     *
+     * @param string $subscriber
+     */
+    public function subscribe(string $subscriber)
+    {
+        $this->subscribers[] = $subscriber;
+
+        return $this;
+    }
+
     public function extend(Container $container, Extension $extension = null)
     {
         $events = $container->make(Dispatcher::class);
 
         foreach ($this->listeners as $listener) {
             $events->listen($listener[0], $listener[1]);
         }
+
+        $app = $container->make('flarum');
+
+        $app->booted(function () use ($events) {
+            foreach ($this->subscribers as $subscriber) {
+                $events->subscribe($subscriber);
+            }
+        });
     }
 }

tests/integration/extenders/EventTest.php

@@ -15,7 +15,8 @@
 use Flarum\Tests\integration\RetrievesAuthorizedUsers;
 use Flarum\Tests\integration\TestCase;
 use Flarum\User\User;
-use Illuminate\Contracts\Bus\Dispatcher;
+use Illuminate\Contracts\Bus\Dispatcher as BusDispatcher;
+use Illuminate\Contracts\Events\Dispatcher;
 use Symfony\Component\Translation\TranslatorInterface;
 
 class EventTest extends TestCase
@@ -33,7 +34,7 @@ protected function buildGroup()
             ],
         ]);
 
-        $bus = $this->app()->getContainer()->make(Dispatcher::class);
+        $bus = $this->app()->getContainer()->make(BusDispatcher::class);
 
         return $bus->dispatch(
             new CreateGroup(User::find(1), ['attributes' => [
@@ -81,6 +82,32 @@ public function custom_listener_works_with_class_with_handle_method_and_can_inje
 
         $this->assertEquals('core.group.admin', $group->name_singular);
     }
+
+    /**
+     * @test
+     */
+    public function custom_subscriber_works()
+    {
+        // Because it injects a translator, this also tests that stuff can be injected into this callback.
+        $this->extend((new Extend\Event)->subscribe(CustomSubscriber::class));
+
+        $group = $this->buildGroup();
+
+        $this->assertEquals('core.group.admin', $group->name_singular);
+    }
+
+    /**
+     * @test
+     */
+    public function custom_subscriber_applied_after_app_booted()
+    {
+        // Because it injects a translator, this also tests that stuff can be injected into this callback.
+        $this->extend((new Extend\Event)->subscribe(CustomSubscriber::class));
+
+        $group = $this->buildGroup();
+
+        $this->assertEquals('booted', $group->name_plural);
+    }
 }
 
 class CustomListener
@@ -97,3 +124,26 @@ public function handle(Created $event)
         $event->group->name_singular = $this->translator->trans('core.group.admin');
     }
 }
+
+class CustomSubscriber
+{
+    protected $bootedAtConstruct;
+    protected $translator;
+
+    public function __construct(TranslatorInterface $translator)
+    {
+        $this->bootedAtConstruct = app('flarum')->isBooted();
+        $this->translator = $translator;
+    }
+
+    public function subscribe(Dispatcher $events)
+    {
+        $events->listen(Created::class, [$this, 'whenGroupCreated']);
+    }
+
+    public function whenGroupCreated(Created $event)
+    {
+        $event->group->name_singular = $this->translator->trans('core.group.admin');
+        $event->group->name_plural = $this->bootedAtConstruct ? 'booted' : 'not booted';
+    }
+}