Chapter 3. Hooks, Actions, and Triggers
A common goal when working with Drupal is for something to happen when a certain event takes place. For example, a site administrator may want to receive an e-mail message when a message is posted. Or a user should be blocked if certain words appear in a comment. This chapter describes how to hook into Drupal's events to have your own code run when those events take place.
Understanding Events and Triggers
Drupal proceeds through a series of events as it goes about its business. These internal events are times when modules are allowed to interact with Drupal's processing. Table 3-1 shows some of Drupal's events.
Table 3.1. Examples of Drupal Events
Creation of a node
Deletion of a node