^Status|Draft|
^Todo|More examples, proof read|

====== Hooks ======
Hooks are basically files included at the start of Kohana, to be more specific they are loaded in the Kohana::setup() method. At this time these files are loaded, so their methods can be used
  * index.php
  * core/Bootstrap.php
  * core/Benchmark.php 
  * core/utf8.php 
  * core/Event.php 
  * core/Kohana.php 

No **event** has been started yet, the first to be started is **system.ready**

Hook files should be put in ''application/hooks'' or similarly in a module folder.


===== Configuring hooks =====
To configure hooks edit ''config.php'' in your application/config directory.
Look the option like this:

**File: config.php**
<code php>

$config['enable_hooks'] = FALSE;
</code>

Set ''$config['enable_hooks']'' to ''TRUE'' and all files in the hooks directory (''application/hooks'') will be included and the code will be executed.

**Example** config.php
<code php>
//To include all files in application/hooks
$config['enable_hooks'] = TRUE;

</code>


===== Hooks and events =====
The power of hooks mainly comes from the [[core:event|Events]] class. Hooks are loaded before any of the events are started. This means you can use a hook to modify an event's callbacks. For example you could load the following file as a hook

**Example** hooks/power.php
<code php>
class Power {
 public function Kohana(){
   Event::$data = Event::$data.'<!-- Powered by Kohana-->';
 }

}
Event::add('system.display', array('Power', 'Kohana'));
</code>

This will add a callback to the the system.display event. The callback is to the method Power::Kohana. Power::Kohana adds a small notice to the bottom of each page (<!-- Powered by Kohana-->). It utilizes the Event::$data to manipulate the final output. See [[core:event#data|Events]] for details.


===== Constants =====
When using hooks you might need to get under the hood of Kohana. When the hooks are loaded these constants are set in index.php

  * EXT - contains the default file extension used for files in Kohana. Defaults to '.php'
  * KOHANA - basename
  * DOCROOT - dirname
  * APPPATH - path to the application directory
  * SYSPATH - path to the system directory
  * MODPATH - path to the modules directory