Correct way to share functions/methods between Module and Extension

Question

I'm just getting acquainted with Add-on development beyond basic plugins and I'm not exactly sure the proper way to organize my files.

I have a base Module file, mod.xxxx.php that has a handful of methods within. I am now realizing I need an extension as well to hook into a few base EE hooks. Within the extension, I want to use a few helper methods from my module but I'm not sure the proper way to share them between the Module and Extension.

I tried

if (class_exists('Modulename') === false)
{
    require_once PATH_THIRD.'modulename/mod.modulename.php';
}
$modulename = new Modulename();

And then called

$modulename->modulemethod($variable);

In the extension, but it's not returning the right type, rather an empty array.

Should these "helper" functions really be moved into a helper file and then loaded into both the extension and the module using the load->helper function of CI?

Answer 1

You should create a library, which is just a PHP class stored in system/expressionengine/third_party/your_addon_name/libraries/.

<?php

class Your_library {
  public function do_something()
  {
     return 'foo';
  }
}

Then in your module / extension, you'd be able to do this:

ee()->load->library('your_library');

// prints out foo
echo ee()->your_library->do_something();

This is the preferred way to share code between the various add-on types.