Get user roles through Moodle Webservice - api

Question

I’ve been trying to find a way to get a user’s roles back through the Moodle webservice API.
I know there are no endpoints to do this but I cannot retrieve them directly from the database because I do not have access to the client’s database.
Is there another way to do that?

Answer 1

You may code a solution along this lines:
Create a barebones plugin with the usual boilerplate code (version.php and so on), for example a local plugin. You can use this other plugin to generate the boilerplate code: https://moodle.org/plugins/tool_pluginskel
In 'db/services.php' register a new external function and expose it in a new or existing service. Docs here: https://docs.moodle.org/dev/Adding_a_web_service_to_a_plugin and here https://docs.moodle.org/dev/Web_services_API . For example:
$functions = [
'local_myplugin_get_user_roles' => [
'classname' => external::class,
'methodname' => 'get_user_roles',
'description' => 'gets user roles',
'type' => 'read',
],
];
$services = [
'My services' => [
'functions' => [
'local_myplugin_get_user_roles',
],
'enabled' => 1,
'restrictedusers' => 0,
'shortname' => 'local_myplugin',
'downloadfiles' => 0,
'uploadfiles' => 0,
],
];
Write an external class (for example in a external.php file) for your plugin (referenced in the function definition you coded before). In this class write the code for the defined external function (that will fetch the roles for a user given a user id, for example), including the input and output handlers. Example here: https://docs.moodle.org/dev/External_functions_API#externallib.php
Within your external function, to get a list of user roles given a context, userid, etc. you may use the global helper get_user_roles. Do not forget to write in this external function the code needed to validate input parameters and so on.
To properly expose your new service and external function to an external system you need to follow this settings guidelines as a Moodle admin: YOUR_MOODLE_INSTANCE_URL/admin/settings.php?section=webservicesoverview . At the end you will generate a user (web service consumer) and a token, that you can set in your external system to consume the Moodle service.
Happy coding.