How to make authorization for a proxy?

Question

Computer networks

Hello, I'm interested in the question, how can I make authorization for a proxy server?
The option to allow access by IP is not suitable, you need to specifically define the user in some way so that you can apply different settings for different users.
Proxy self-written on node.js
PS Since I searched for a long time and did not find anything, I will even listen to the options for "crutches")