This is part two on how to write an OAuth client and server. If you have not read Part One yet, you should take a look at it.

This post covers a lesser-known part of OAuth, which is console-based app authentication. You’ve probably seen it in action with the gcloud and heroku apps. Console-based app OAuth generally follows the same flow as that of a web app (auth code flow) with a few changes thrown in. I will explain how it works along with code examples. The code is written in Python and was tested on the 3.10 version. You can find it here.

OAuth (Open Authorization) is an open standard for access delegation, commonly used for internet users to grant websites or applications access to their information on other websites without giving them the passwords. It’s quite a mouthful, right? That’s the definition from Wikipedia for the specification behind the Login With Facebook, Login With Google, and Login with [Fill In Popular Site] buttons we see whenever we want to register or login into our various web accounts.