Spring MVC “redirect:” prefix always redirects to http — how do I make it stay on https?

Question

I solved this myself, but I spent so long discovering such a simple solution, I figured it deserved to be documented here.

I have a typical Spring 3 MVC setup with

Answer 1

Since Spring Boot 2.1 you have to add the following configuration to your application.properties:

server.use-forward-headers=true 

or application.yml:

server:
  use-forward-headers: true