EVENTFUL // CAKEPHP

Event-driven programming for CakePHP

/!\ Repo Layout Updated /!\

For the old folder layout check the legacy branch. The new master branch featuring this README will be written on 1.3 and undergo some major changes in the near future.

Installation

Just clone/unzip this repo into your plugins directory.

cd app/plugins
git clone git://github.com/m3nt0r/eventful-cakephp.git eventful

Conventions

Inside your app/controllers and app/models directories simply create new php files with the "_events.php" suffix. Here is a working example listing.

    -rw-r--r--@  users_controller.php
    -rw-r--r--@  users_events.php
    -rw-r--r--@  pages_controller.php
    -rw-r--r--@  pages_events.php
    ...

Inside the event handler classes you must prefix all methods with the on keyword.

    // example dispatch
    $this->Event->dispatch('paypalComplete');
    $this->Event->dispatch('paypalCancel');
    
    // good
    function onPaypalComplete($event);
    function onPaypalCancel($event);
    
    // bad
    function paypalComplete($event);    
    function paypal_cancel($event);

Code Example

I assume you already know about CRUD and other CakePHP terminology. The following is not a working program and should only give you an idea of how the system was designed.

Trigger from a controller

In a controller, include the EventComponent and use its 'dispatch' method to trigger an event. The first parameter sets which name the responding event handler should have. In this case we allow "onSignup"-handlers to respond.

class UsersController extends AppController {
  public $components = array('Eventful.Event');
  public function add() { 
    // save() etc... 
    // now tell other parts of the application what happened
    $response = $this->Event->dispatch('signup', array(
      'user' => $this->User->data
    ));
  }
}

Example Event Classes

You may have any number of event classes and they may contain any number of methods (handlers). Every class is examined once an event is dispatched and check if the class is able to handle the request. The example above will run the code within onSignup in both classes.

// statistics_events.php
class StatisticEvents extends AppControllerEvents {
  public function onSignup($event) { 
    ClassRegistry::init('Statistic')->incrUsers();
  }	
  public function onVisit($event) { 
    ClassRegistry::init('Statistic')->incrVisits();
  }
  // and others...
}

// mailing_events.php
class MailingEvents extends AppControllerEvents {
  public function onSignup($event) { 
    $userEmail = $event->user['email'];
    // ... send mail or smth
    return array('sentVerify' => $result);
  }	
}

The Result

Back in our controller we could now examine the response of each handler and maybe change the outcome of the action.

class UsersController extends AppController {
  public $components = array('Eventful.Event');
  public function add() { 
    // post-save()
    $response = $this->Event->dispatch('signup', array(
      'user' => $this->User->data
    ));
    
    // lets evaluate the response
    if (!empty($response['MailingEvents']) 
    and $response['MailingEvents']['sentVerify']) {
      $this->Session->setFlash('Check your inbox for verification.');
    }
  }
}

The Alternative

However, you can also move this logic inside the event handler. I recommend doing so for portability reasons. Inside the action would require managing lots of conditions and constraints, which is not very flexible. You may access the object from which the event originates via the Controller (or Model) property in the $event-param.

class MailingEvents extends AppControllerEvents {
  public function onSignup($event) { 
    $userEmail = $event->user['email'];
    
    $result = $this->Email->send(); // or something..
    if ($result == true) {
      $session = event->Controller->Session;
      $session->setFlash('Check your inbox for verification.');
    }
    return array('sentVerify' => $result);
  }	
}

License

MIT License
Copyright (c) 2008-2013, Kjell Bublitz.
See LICENSE for more info.