Php Yii，如何注册由控制器提出的事件

What I want to do: Register a component to an event raised by a controller.

In my config main.php:

'preload' => array(MessageConsumer) // actually an impl class of interface

In my MessageConsumer impl

public function init() {
    Yii::app()->getController()->onMessageReceived = array($this, 'onMessageReceived');
}

Expected result: when the init method fires the consumer is registered to the current controller.

Actual result: there's no current controller yet. It seems the pre-load is performed before the webapplication does the controller magic.

So I tried something like:
In my MessageConsumer impl:

public function init() {
    $self = $this;
    Yii::app()->onBeginRequest(function() use ($self) {
        $controller = Yii::app()->getController();
        if($controller instanceof MessagingController) {
            Yii::app()->getController()->onMessageReceived = array($self, 'onMessageReceived');
        }
    });
}

Which doesn't work either because it seems the init() is called after the onBeginRequest() event is raised by the webapp.

Is there a way to register to events raised by a controller without explicitly linking the component to the controller class? Obviously I could register the listener in the constructor of the controller but I want to loosely couple the 2 components by using configuration.

Maybe there's some event like "onComponentLoaded" for which I could register? Since a Controller is a component I'd expect the Yii core to fire the event whenever there's a component loaded if there's such an event at all.

I presume this is what you looking for, the onBeforeAction();

<?php
class YourController extends Controller
{
    //this action is executed before any controller action
    protected function beforeAction($action)
    {
        //do stuff before controll action
        return true;
    }

    //the rest ofyour controller actions and stuff
    public function actionIndex(){
        //[...]
    }
}
?>