How to get user details of the user who has triggered REST API service?

Summary:

We can see REST_API_Absence as CREATED_BY and LAST_UPDATED_BY user in ANC_PER_ABS_ENTRIES table. We need to get the actual User name who used the REST API service to create or update Absence entry. Please help us with the query that can get us the user details.

Content (required):

We can create or update absence record using REST API service. In ANC_PER_ABS_ENTRIES table we can see REST_API_Absence as CREATED_BY and LAST_UPDATED_BY user but not the actual user. We like to know if there is any way to get actual user name.