Sharepoint REST API - how to get refresh tokens?

Hi,

I'm reading a Sharepoint list using the REST API call with webread. In order to access the Sharepoint list, I needed to generate a token first and was able to do this successfully.

However, it appears this first token expires in a few hours. I've read about getting REFRESH tokens automatically, but cannot for the life of me figure out how to program it. So I keep doing this manually by re-generating a new token from Postman and then copy/pasting it into my Matlab script - not fun!

Has anyone successfully connected to Sharepoint data via REST API calls and able to continually get refresh tokens automatically without user-intervention? I'd really appreciate a step-by-step guide if possible.

Thanks in advance.