This is a very basic HOWTO showing how could one obtain a list of users and their roles via a REST call.
Basically, there are two ways: via bulk actions and via simple query.
Bulk actions (midPoint scripting)
This method is the most powerful, but also quite complex.
Execute this command:
Command to return users and their information
query-all-users-bulk.xml file
Simple query
This is not so powerful and flexible as bulk actions, but may suffice on many occassions.
Execute this command:
Command to return users and their information; with all references resolved to object names
Referencing this file:
Query to select users (all users in this case)