Creating Ancillary Classes¶

get_instance()¶

get_instance()¶

Returns:	Reference to your controller’s instance
Return type:	CI_Controller

Any class that you instantiate within your controller methods can access CodeIgniter’s native resources simply by using the get_instance() function. This function returns the main CodeIgniter object.

Normally, to call any of the available CodeIgniter methods requires you to use the $this construct:

$this->load->helper('url');
$this->load->library('session');
$this->config->item('base_url');
// etc.

$this, however, only works within your controllers, your models, or your views. If you would like to use CodeIgniter’s classes from within your own custom classes you can do so as follows:

First, assign the CodeIgniter object to a variable:

$CI =& get_instance();

Once you’ve assigned the object to a variable, you’ll use that variable instead of $this:

$CI =& get_instance();

$CI->load->helper('url');
$CI->load->library('session');
$CI->config->item('base_url');
// etc.

If you’ll be using get_instance() inside another class, then it would be better if you assign it to a property. This way, you won’t need to call get_instance() in every single method.

Example:

class Example {

        protected $CI;

        // We'll use a constructor, as you can't directly call a function
        // from a property definition.
        public function __construct()
        {
                // Assign the CodeIgniter super-object
                $this->CI =& get_instance();
        }

        public function foo()
        {
                $this->CI->load->helper('url');
                redirect();
        }

        public function bar()
        {
                $this->CI->config->item('base_url');
        }
}

In the above example, both methods foo() and bar() will work after you instantiate the Example class, without the need to call get_instance() in each of them.