Helper Functions

Helpers, as the name suggests, help you with tasks. Each helper file is simply a collection of functions in a particular category. There are URL Helpers, that assist in creating links, there are Form Helpers that help you create form elements, Text Helpers perform various text formatting routines, Cookie Helpers set and read cookies, File Helpers help you deal with files, etc.

Unlike most other systems in CodeIgniter, Helpers are not written in an Object Oriented format. They are simple, procedural functions. Each helper function performs one specific task, with no dependence on other functions.

CodeIgniter does not load Helper Files by default, so the first step in using a Helper is to load it. Once loaded, it becomes globally available in your controller and views.

Helpers are typically stored in your system/helpers directory. Alternately you can create a folder called helpers inside your application folder and store them there. CodeIgniter will look first in your system/application/helpers directory. If the directory does not exist or the specified helper is not located there CI will instead look in your global system/helpers folder.

Loading a Helper

Loading a helper file is quite simple using the following function:

$this->load->helper('name');

Where name is the file name of the helper, without the .php file extension or the "helper" part.

For example, to load the URL Helper file, which is named url_helper.php, you would do this:

$this->load->helper('url');

A helper can be loaded anywhere within your controller functions (or even within your View files, although that's not a good practice), as long as you load it before you use it. You can load your helpers in your controller constructor so that they become available automatically in any function, or you can load a helper in a specific function that needs it.

Note: The Helper loading function above does not return a value, so don't try to assign it to a variable. Just use it as shown.

Loading Multiple Helpers

If you need to load more than one helper you can specify them in an array, like this:

$this->load->helper( array('helper1', 'helper2', 'helper3') );

Auto-loading Helpers

If you find that you need a particular helper globally throughout your application, you can tell CodeIgniter to auto-load it during system initialization. This is done by opening the application/config/autoload.php file and adding the helper to the autoload array.

Using a Helper

Once you've loaded the Helper File containing the function you intend to use, you'll call it the way you would a standard PHP function.

For example, to create a link using the anchor() function in one of your view files you would do this:

<?=anchor('blog/comments', 'Click Here');?>

Where "Click Here" is the name of the link, and "blog/comments" is the URI to the controller/function you wish to link to.

Now What?