Map string UID with agora generated integer UID

Basically, I have a web project where I am using String username as UID to join the channel in the Agora video call. Recently I need to implement individual cloud recording of Agora in the project. As the cloud recording doesn't take a string as a UID I am facing difficulty to figure out which record file belongs to which user as the record file that generates has UID that is an integer. So I need to map username with the integer UID. Could anyone help me with this problem?