[UPDATE]

I've found a cleaner way to deal with it :

sfProjectConfiguration::getActive()->getEventDispatcher()->notify(new sfEvent($this, 'foo.bar'))
 

The old version of this snippet is now useless, you don't need to read it.

[/UPDATE]

This snippet is not a tutorial on symfony events, but you can find some documentation in the book and or in this good tutorial.

The event dispatcher is a very powerfull tool, but you might meet the same issue than me if you want to use it from a Model Class.

Let's take the classic Author/Article project sample.

When an article is added, it might be interesting to trigger an "article.new" event. This event coud be listened by different actors.

Like for instance :

• The cache manager that will update some of the author cache, like an "Author/lastArticles" partial
• The Logger will add a line
• The mail system will send an alert to the admin in charge with the editorial activity of the website
• and so on...

The most obvious place to trigger the event is the Article save() method. Here is the code for Doctrine (the logic is exactly the same for Propel):

Article.class.php

public function save(Doctrine_Connection $conn = null)
{
  if ($this->isNew())
  {
    // Let's trigger the event
    sfContext::getInstance()->getEventDispatcher()->notify(new sfEvent($this, 'article.new'));
  }
  return parent::save($conn);
}
 

Unfortunatly, this code won't work. If you try the "symfony doctrine:build-all-reload" command, here is the error that will be displayed :

Cli

sfException: The "default" context does not exist.
 

Why ? Because symfony tasks don't initialise the sfContext class. And for the moment (symfony version 1.2.4) I don't think there's a clean way to access to the dispatcher object from a Doctrine Class.

Here is my solution : let's build a (very) little singleton class that will provide the dispatcher ressource everywhere in the project, and even when sfContext is not avaible

yourProjectRoot/lib/Fedex.class.php

class Fedex
{
  static protected $instance;
  protected $dispatcher;
  /**
   * The singleton logic http://en.wikipedia.org/wiki/Singleton_pattern#PHP_5
   */
  static public function getInstance()
  {
    if (!self::$instance instanceof self)
    {
      self::$instance = new self;
    }
    return self::$instance;
  }
 
  public function setEventDispatcher(sfEventDispatcher $dispatcher)
  {
    $this->dispatcher = $dispatcher;
  }
 
  public function getEventDispatcher()
  {
    return $this->dispatcher;
  }
}
 

Of course, you first have to give to the Fedex class a link the delivery ressource. Let's do it with the very first class called by the script of the project :

yourProjectRoot/config/ProjectConfiguration.class.php

public function setup()
{
  // add after all your setup stuffs
 
  require_once(dirname(__FILE__).'/../lib/Fedex.class.php');
  Fedex::getInstance()->setEventDispatcher($this->dispatcher);
}
 

That's it, you're done. The Fedex class will deliver the dispatcher ressource everywhere in your project through Fedex::getInstance()->getEventDispatcher() And it works even when the sfContext class is not avaible

Article.class.php

public function save(Doctrine_Connection $conn = null)
{
  if ($this->isNew())
  {
    Fedex::getInstance()->getEventDispatcher()->notify(new sfEvent($this, 'article.new'));
  }
  return parent::save($conn);
}
 

The important thing is that this little class doesn't modify any part of the symfony event system. It just provide you an alternative way to access to it.