Magento PHP Developer's Guide - Second Edition

Events and observers

The event and observer pattern is probably one of Magento's more interesting features, as it allows developers to extend Magento in critical parts of the application flow.

In order to provide more flexibility and facilitate interaction between the different modules, Magento implements an Event/Observer pattern. This pattern allows modules to be loosely coupled.

There are two parts to this system, an Event dispatch with the object and event information and an Observer listening to a particular event:

Event dispatch

Events are created or dispatched using the Mage::dispatchEvent() function. The core team has already created several ...