Helper Functions

What are Helpers?

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, Test Helpers perform various text formatting routines, Cookie Helpers set and read cookies, Filesystem 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, or app/Helpers directory.

Loading Helpers 

Note

The URL Helper is always loaded so you do not need to load it yourself.

Loading a Helper 

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

<?php

helper('name');

The above code loads the name_helper.php file.

Important

CodeIgniter helper file names are all lowercase. Therefore, helper('Name') will not work on case-sensitive file systems such as Linux.

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

<?php

helper('cookie');

Note

The helper() function does not return a value, so don’t try to assign it to a variable. Just use it as shown.

Auto-Discovery and Composer Packages

By default, CodeIgniter will search for the helper files in all defined namespaces by Auto-Discovery. You can check your defined namespaces by the spark command. See Confirming Namespaces.

If you use many Composer packages, you will have many defined namespaces. CodeIgniter will scan all namespaces by default.

To avoid wasting time scanning for irrelevant Composer packages, you can manually specify packages for Auto-Discovery. See Specify Composer Packages for details.

Or you can specify a namespace for a helper that you want to load.

Load Order

The helper() function will scan through all defined namespaces and load in ALL matching helpers of the same name. This allows any module’s helpers to be loaded, as well as any helpers you’ve created specifically for this application.

The load order is as follows:

app/Helpers - Files loaded here are always loaded first.
{namespace}/Helpers - All namespaces are looped through in the order they are defined.
system/Helpers - The base file is loaded last.

Loading Multiple Helpers 

If you need to load more than one helper at a time, you can pass an array of file names in and all of them will be loaded:

<?php

helper(['cookie', 'date']);

Loading in a Controller 

A helper can be loaded anywhere within your controller methods (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 method, or you can load a helper in a specific method that needs it.

However if you want to load in your controller constructor, you can use the $helpers property in Controller instead. See Controllers.

Loading from Specified Namespace 

By default, CodeIgniter will search for the helper files in all defined namespaces and load all found files.

If you want to load only a helper in a specific namespace, prefix the name of the helper with the namespace that it can be located in. Within that namespaced directory, the loader expects it to live within a sub-directory named Helpers. An example will help understand this.

For this example, assume that we have grouped together all of our Blog-related code into its own namespace, Example\Blog. The files exist on our server at Modules/Blog/. So, we would put our Helper files for the blog module in Modules/Blog/Helpers/. A blog_helper file would be at Modules/Blog/Helpers/blog_helper.php. Within our controller we could use the following command to load the helper for us:

<?php

helper('Example\Blog\blog');

You can also use the following way:

<?php

helper('Example\Blog\Helpers\blog');

Note

The functions within files loaded this way are not truly namespaced. The namespace is simply used as a convenient way to locate the files.

Auto-loading Helpers 

New in version 4.3.0.

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 app/Config/Autoload.php file and adding the helper to the $helpers property.

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:

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

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

Creating Helpers 

Creating Custom Helpers 

The helper filename is the helper name and _helper.php.

For example, to create info helper, you’ll create a file named app/Helpers/info_helper.php, and add a function to the file:

<?php

// app/Helpers/info_helper.php
use CodeIgniter\CodeIgniter;

/**
 * Returns CodeIgniter's version.
 */
function ci_version(): string
{
    return CodeIgniter::CI_VERSION;
}

You can add as many functions as you like to a single helper file.

“Extending” Helpers 

To “extend” Helpers, create a file in your app/Helpers folder with an identical name to the existing Helper.

If all you need to do is add some functionality to an existing helper - perhaps add a function or two, or change how a particular helper function operates - then it’s overkill to replace the entire helper with your version. In this case, it’s better to simply “extend” the Helper.

Note

The term “extend” is used loosely since Helper functions are procedural and discrete and cannot be extended in the traditional programmatic sense. Under the hood, this gives you the ability to add to, or to replace the functions a Helper provides.

For example, to extend the native Array Helper you’ll create a file named app/Helpers/array_helper.php, and add or override functions:

<?php

// any_in_array() is not in the Array Helper, so it defines a new function
function any_in_array($needle, $haystack)
{
    $needle = is_array($needle) ? $needle : [$needle];

    foreach ($needle as $item) {
        if (in_array($item, $haystack, true)) {
            return true;
        }
    }

    return false;
}

// random_element() is included in Array Helper, so it overrides the native function
function random_element($array)
{
    shuffle($array);

    return array_pop($array);
}

Important

Do not specify the namespace App\Helpers.

See Load Order for the order in which helper files are loaded.

Now What?

In the Table of Contents, you’ll find a list of all the available Helpers. Browse each one to see what they do.