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The symfony core components are decoupled thanks to an sfEventDispatcher object. The event dispatcher manages the communication between core components.

Any object can notify an event to the dispatcher, and any other object can connect to the dispatcher to listen to a specific event.

An event is just a name composed of a namespace and a name separated by a dot (.).

Usage

You can notify an event by first creating an event object:

$event = new sfEvent($this, 'user.change_culture', array('culture' => $culture));

And notify it:

$dispatcher->notify($event);

The sfEvent constructor takes three arguments:

• The "subject" of the event (most of the time, this is the object notifying the event, but it can also be null)
• The event name
• An array of parameters to pass to the listeners

To listen for an event, connect to that event name:

$dispatcher->connect('user.change_culture', array($this, 'listenToChangeCultureEvent'));

The connect method takes two arguments:

• The event name
• A PHP callable to call when the event is notified

Here is an implementation example of a listener:

public function listenToChangeCultureEvent(sfEvent $event)
{
  // change the message format object with the new culture
  $this->setCulture($event['culture']);
}

The listener gets the event as the first argument. The event object has several methods to get event information:

• getSubject(): Gets the subject object attached to the event
• getParameters(): Returns the event parameters

The event object can also be accessed as an array to get its parameters.

Event Types

Events can be triggered by three different methods:

• notify()
• notifyUntil()
• filter()

notify

The notify() method notifies all listeners. The listeners cannot return a value and all listeners are guaranteed to be executed.

notifyUntil

The notifyUntil() method notifies all listeners until one stops the chain by returning a true value.

The listener that stops the chain may also call the setReturnValue() method.

The notifier can check if a listener has processed the event by calling the isProcessed() method:

if ($event->isProcessed())
{
  // ...
}

filter

The filter() method notifies all listeners that they can filter the given value, passed as a second argument by the notifier, and retrieved by the listener callable as the second argument. All listeners are passed the value and they must return the filtered value. All listeners are guaranteed to be executed.

The notifier can get the filtered value by calling the getReturnValue() method:

$ret = $event->getReturnValue();

Events

• application
  • application.log
• command
  • command.log
  • command.pre_command
  • command.post_command
  • command.filter_options
• configuration
  • configuration.method_not_found
• component
  • component.method_not_found
• context
  • context.load_factories
• controller
  • controller.change_action
  • controller.method_not_found
  • controller.page_not_found
• plugin
  • plugin.pre_install
  • plugin.post_install
  • plugin.pre_uninstall
  • plugin.post_uninstall
• request
  • request.filter_parameters
  • request.method_not_found
• response
  • response.method_not_found
  • response.filter_content
• routing
  • routing.load_configuration
• task
  • task.cache.clear
• template
  • template.filter_parameters
• user
  • user.change_culture
  • user.method_not_found
  • user.change_authentication
• view
  • view.configure_format
  • view.method_not_found
• view.cache
  • view.cache.filter_content

application

application.log

Notify method: notify

Default notifiers: lot of classes

The application.log event is the mechanism used by symfony to do the logging for web request (see the logger factory). The event is notified by most symfony core components.

application.throw_exception

Notify method: notifyUntil

Default notifiers: sfException

The application.throw_exception event is notified when an uncaught exception is thrown during the handling of a request.

You can listen to this event to do something special whenever an uncaught exception is thrown( like sending an email, or logging the error). You can also override the default exception management mechanism of symfony by processing the event.

command

command.log

Notify method: notify

Default notifiers: sfCommand* classes

The command.log event is the mechanism used by symfony to do the logging for the symfony CLI utility (see the logger factory).

command.pre_command

Notify method: notifyUntil

Default notifiers: sfTask

The command.pre_command event is notified just before a task is executed.

command.post_command

Notify method: notify

Default notifiers: sfTask

The command.post_command event is notified just after a task is executed.

command.filter_options

Notify method: filter

Default notifiers: sfTask

The command.filter_options event is notified before the task CLI options are parsed. This event can be used to filter the options passed by the user.

configuration

configuration.method_not_found

Notify method: notifyUntil

Default notifiers: sfProjectConfiguration

The configuration.method_not_found event is notified when a method is not defined in the sfProjectConfiguration class. By listening to this event, a method can be added to the class, without using inheritance.

component

component.method_not_found

Notify method: notifyUntil

Default notifiers: sfComponent

The component.method_not_found event is notified when a method is not defined in the sfComponent class. By listening to this event, a method can be added to the class, without using inheritance.

context

context.load_factories

Notify method: notify

Default notifiers: sfContext

The context.load_factories event is notified once per request by the sfContext object just after all factories have been initialized. This is the first event to be notified with all core classes initialized.

controller

controller.change_action

Notify method: notify

Default notifiers: sfController

The controller.change_action is notified just before an action is executed.

controller.method_not_found

Notify method: notifyUntil

Default notifiers: sfController

The controller.method_not_found event is notified when a method is not defined in the sfController class. By listening to this event, a method can be added to the class, without using inheritance.

controller.page_not_found

Notify method: notify

Default notifiers: sfController

The controller.page_not_found is notified whenever a 404 error is generated during the handling of a request.

You can listen to this event to do something special whenever a 404 page occurs, like sending an email, or logging the error. the event.

plugin

plugin.pre_install

Notify method: notify

Default notifiers: sfPluginManager

The plugin.pre_install event is notified just before a plugin will be installed.

plugin.post_install

Notify method: notify

Default notifiers: sfPluginManager

The plugin.post_install event is notified just after a plugin has been installed.

plugin.pre_uninstall

Notify method: notify

Default notifiers: sfPluginManager

The plugin.pre_uninstall event is notified just before a plugin will be uninstalled.

plugin.post_uninstall

Notify method: notify

Default notifiers: sfPluginManager

The plugin.post_uninstall event is notified just after a plugin has been uninstalled.

request

request.filter_parameters

Notify method: filter

Default notifiers: sfWebRequest

The request.filter_parameters event is notified when the request parameters are initialized.

request.method_not_found

Notify method: notifyUntil

Default notifiers: sfRequest

The request.method_not_found event is notified when a method is not defined in the sfRequest class. By listening to this event, a method can be added to the class, without using inheritance.

response

response.method_not_found

Notify method: notifyUntil

Default notifiers: sfResponse

The response.method_not_found event is notified when a method is not defined in the sfResponse class. By listening to this event, a method can be added to the class, without using inheritance.

response.filter_content

Notify method: filter

Default notifiers: sfResponse

The response.filter_content event is notified before a response is sent. By listening to this event, you can manipulate the content of the response before it is sent.

routing

routing.load_configuration

Notify method: notify

Default notifiers: sfRouting

The routing.load_configuration event is notified when the routing factory loads the routing configuration.

task

task.cache.clear

Notify method: notifyUntil

Default notifiers: sfCacheClearTask

The task.cache.clear event is notified whenever the user clears the cache from the CLI with the cache:clear task.

template

template.filter_parameters

Notify method: filter

Default notifiers: sfViewParameterHolder

The template.filter_parameters event is notified before a view file is rendered. By listening to this event you can access and manipulate variables passed to a template.

user

user.change_culture

Notify method: notify

Default notifiers: sfUser

The user.change_culture event is notified when the user culture is changed during a request.

user.method_not_found

Notify method: notifyUntil

Default notifiers: sfUser

The user.method_not_found event is notified when a method is not defined in the sfUser class. By listening to this event, a method can be added to the class, without using inheritance.

user.change_authentication

Notify method: notify

Default notifiers: sfBasicSecurityUser

The user.change_authentication event is notified whenever the user authentication status changes.

view

view.configure_format

Notify method: notify

Default notifiers: sfView

The view.configure_format event is notified by the view when the request has the sf_format parameter set. The event is notified after symfony has done simple things like changing setting or unsetting the layout. This event allows the view and the response object to be changed according to the requested format.

view.method_not_found

Notify method: notifyUntil

Default notifiers: sfView

The view.method_not_found event is notified when a method is not defined in the sfView class. By listening to this event, a method can be added to the class, without using inheritance.

view.cache

view.cache.filter_content

Notify method: filter

Default notifiers: sfViewCacheManager

The view.cache.filter_content event is notified whenever a content is retrieved from the cache.