title: What's the de facto standard for a Reverse Proxy to tell the backend SSL is used?
body: <p>I have a reverse proxy that does HTTPS on the outside, but HTTP on the inside.</p>
  
  <p>This means that by default in-app URLs will have HTTP as the scheme, as this is the way it's being contacted.</p>
  
  <p>How can the proxy tell the backend that HTTPS should be used?</p>