Customized login auth plugin

[fefrei (Felix Freiberger)]

Discourse’s SSO support does exactly this:

Setup DiscourseConnect - Official Single-Sign-On for Discourse (sso)

DiscourseConnect is a core Discourse feature that allows you to configure “Single Sign-On (SSO)” to completely outsource all user registration and login from Discourse to another site. Offered to our standard, business and enterprise hosting customers. (Feb 2021) ‘Discourse SSO’ is now ‘DiscourseConnect’. If you are running an old version of Discourse, the settings below will be named sso_... rather than discourse_connect_... The Problem Many sites wishing to integrat…