2. Matt Agar
Technical Director at August
matt.agar@august.com.au

3. Symfony
Components

4. “...the foundation of the Symfony
full-stack framework, but they can
also be used standalone even if you
don't use the framework...”
symfony.com/components

5. BrowserKit, ClassLoader, Config, Console,
CssSelector, Debug, DependencyInjection,
DomCrawler, EventDispatcher,
ExpressionLanguage, Filesystem, Finder, Form,
HttpFoundation, HttpKernel, Locale, Intl, Icu,
OptionsResolver, Process, PropertyAccess,
Routing, Security, Serializer, Stopwatch,
Templating, Translation, Validator, Yaml

6. BrowserKit, ClassLoader, Config, Console,
CssSelector, Debug, DependencyInjection,
DomCrawler, EventDispatcher,
ExpressionLanguage, Filesystem, Finder, Form,
HttpFoundation, HttpKernel, Locale, Intl, Icu,
OptionsResolver, Process, PropertyAccess,
Routing, Security, Serializer, Stopwatch,
Templating, Translation, Validator, Yaml

7. Powerful

8. Sculpin, Symfony Full Stack,
phpBB, Drupal, Thelia,
phpspec, Silex, Behat,
Guzzle, Laravel,
phpDocumentor, Carew

9. Simple

10. Getting Started

11. // Clone directly from github.com/symfony/EventDispatcher
$ git clone https://github.com/symfony/EventDispatcher.git

12. // Install using Composer
$ curl -s http://getcomposer.org/installer | php
$ php composer.phar require symfony/event-dispatcher

13. Events
The Dispatcher
Listeners

14. 1. Events

15. Instances of
Symfony/Component/EventDispatcher/Event

16. Events have a
unique name

17. kernel.request
kernel.response
form.bind
form.post_set_data
console.command
console.exception

18. namespace AcmeStoreBundle;
final class StoreEvents
{
/**
* The store.order event is thrown each time an order is created
* in the system.
*/
const STORE_ORDER = 'store.order';
}

19. No need for
Event objects
$dispatcher->dispatch('store.order');

20. namespace AcmeStoreBundleEvent;
use SymfonyComponentEventDispatcherEvent;
use AcmeStoreBundleOrder;
class StoreOrderEvent extends Event {
protected $order;
public function __construct(Order $order) {
$this->order = $order;
}
public function getOrder() {
return $this->order;
}
}

21. $event->stopPropagation();
$event->isPropagationStopped();

22. Event Extras

23. SymfonyComponentEventDispatcher
GenericEvent

24. use SymfonyComponentEventDispatcherGenericEvent;
$storeOrderEvent = new GenericEvent(
$order,
array('a' => 'b', 'c' => 0)
);
// Implements ArrayAccess and IteratorAggregate
echo $event['a'];
$order === $storeOrderEvent->getSubject();

25. 2. The Dispatcher

26. use SymfonyComponentEventDispatcherEventDispatcher;
$dispatcher = new EventDispatcher();

27. Use the Single
Instance

28. // access the dispatcher service in a controller
$dispatcher = $this->container->get('event_dispatcher');

29. # app/config/config.yml
services:
event_generator:
class: AcmeHelloBundleEventGenerator
arguments: ["@event_dispatcher"]

30. namespace AcmeHelloBundle;
use SymfonyComponentEventDispatcherEventDispatcherInterface;
class EventGenerator
{
protected $dispatcher;
public function __construct(EventDispatcherInterface $dispatcher)
{
$this->dispatcher = $dispatcher;
}
}

31. Dispatching
events

32. // event name only
$dispatcher->dispatch('store.order');
// create the StoreOrderEvent and dispatch it
$event = new StoreOrderEvent($order);
$dispatcher->dispatch(StoreEvents::STORE_ORDER, $event);

33. $a = $dispatcher->dispatch('store.event', $b);
$a === $b; // true
// returns the dispatcher created event
$dispatcher->dispatch('foo.event')->isPropagationStopped()

34. Dispatcher Extras

35. SymfonyComponentEventDispatcher
ImmutableEventDispatcher

36. SymfonyComponentEventDispatcher
ContainerAwareEventDispatcher

37. SymfonyComponentEventDispatcher
DebugTraceableEventDispatcher

38. 3. The Listeners

39. Basic Listeners

40. $dispatcher->addListener(
'event.name',
$listener, // PHP callable
$priority = 0
);

41. # app/config/config.yml
services:
event_listener:
class: AcmeHelloBundleEventListener
tags:
- { name: kernel.event_listener,
event: kernel.exception,
method: onKernelException,
priority: 0 }

42. Subscribers

43. // Implements EventSubscriberInterface
$subscriber = new StoreSubscriber();
$dispatcher->addSubscriber($subscriber);

44. class StoreSubscriber implements EventSubscriberInterface {
public static function getSubscribedEvents() {
return array(
'kernel.request' => 'onKernelRequest',
'store.order' => array('onStoreOrder', 5),
'kernel.response' => array(
array('onKernelResponsePre', 10),
array('onKernelResponsePost', 0),
)
);
}
}

45. # app/config/config.yml
services:
event_listener:
class: AcmeHelloBundleEventSubscriber
tags:
- { name: kernel.event_subscriber }

46. Listener Extras

47. // Event name and the dispatcher passed to listener
public function onStoreOrder(
Event $event,
$eventName,
EventDispatcherInterface $eventDispatcher
)

48. What next?

49. Thank You!
Questions?