Authentication plugins are placed inside Moodle's auth folder. They have two major requirements: an auth.php file and a language file. In this section, we will cover the minimal requirements of creating as basic a module as we can. This module will be called simple.
Authentication plugins are of medium complexity. They don't require many files to be defined. However, there are several functions that can be defined in the plugin classes. Let's have a look at the primary file.
The auth.php file needs to include /lib/authlib.php. This library defines the auth_plugin_base class that is the basis for any new authentication module. Within the auth.php file, we need to extend class auth_plugin_base as auth_plugin_<name>, where name is the name of the module's folder. For the simple authentication module this looks similar to the following:
class auth_plugin_simple extends auth_plugin_base {
As a minimum...