^Status|Draft|
^Todo|Expand, clarify, elaborate and more examples. Autoloading via Kohana::auto_load and naming rules.|


====== Loading resources ======
<box|Note:>
Some libraries are always loaded automatically: [[libraries:uri|URI]], Router and [[libraries:input|Input]].
</box>

===== Autoloading =====
PHP has functionality to [[http://php.net/manual/en/language.oop5.autoload.php|automatically load]] files if a certain class has not been loaded yet. Kohana employs this functionality.

**Example**
<code php> 
$user = new User_Model;
$cache = new Cache();
html::stylesheet();
$this->layout = new View('layout');
</code>

===== Loading libraries =====
Libraries can be autoloaded:
<code php>
$this->cache= new Cache;
echo $this->cache->get('mycache');
</code>

Some of the libraries ([[libraries:calendar|Calendar]], [[libraries:captcha|Captcha]], [[libraries:image|Image]], [[libraries:orm|ORM]], [[libraries:pagination|Pagination]], [[libraries:validation|Validation]], [[core:view|View]]) provide another method, ''factory'', to load instantiate and use them. This way methods can be chained efficiently:


**Examples:**
<code php>
View::factory('some_view')->set(array('title' => 'Welcome to Kohana !', 'breadcrumb' => 'Kohana > Welcome'))->render(true);

$post = Validation::factory($_POST)->pre_filter('trim')->add_rules('field1', 'length[2,15]','alpha_numeric');

$page = ORM::factory('page')->where('name', 'index')->find();

$image = Image::factory('moo.jpg')->resize(400, NULL)->crop(400, 350, 'top')->sharpen(20)->quality(75);

</code>

It is recommended to access the Database and Session objects via the singleton instance, rather than using ''new'':

''$db = Database::instance()'' and ''$s = Session::instance()'' Note: If the objects do not exist, they will be instantiated.

Example: Load Session and Database in a Base Controller, and access the objects in your extended controllers.
<code php>
// Base Controller code
$this->db = Database::instance($db_group);
$this->session = Session::instance();
// Now in any controller which extends Base Controller
$var = $this->session->get('var');
$query = $this->db->query('SELECT * FROM `table`);
</code>

===== Loading database=====
Loading the database can also be done like this
<code php>
$this->db = new Database;
</code>

**__Loading database in models__**

In models the database is loaded automatically as far as you call ''parent::%%__%%construct();'' in your constructor.

<code php>
public function __construct()
{
	// load database library into $this->db (can be omitted if not required)
	parent::__construct();
}
</code>


===== Loading helpers =====

Using a helper is fairly simple. Just call method as a static method. The class will be loaded automatically
<code php>
echo url::base();
echo html::breadcrumb();
</code>

===== Loading views =====
Views are the final output of Kohana. They can be embedded into each other so as to help you in making your site. The actual rendering of a view is not done when you load one.  More on views can be found on the [[general:views|views page]]. Information on the view class can be found on the [[core:view|View class]] page.

**Example**
<code php>
$this->layout=new View('layouts/layout'); // will load the file views/layouts/layout.php

//will render the view
$this->layout->render(TRUE);

</code>






===== Loading models =====

Loading a model is the same as loading a view except you must append '_Model' to your model name. More can be found on the [[general::models|Models]] page.

For instance your model is User_Model, the filename would be ''models/user.php'' The loading of the model happens in the controller.
**Example**
<code php>
$user = new User_Model;
$name = $user->get_user_name($id); //get_user_name is a method defined in User_Model 
</code>