Is there a clean way to redirect all attempts to going to an HTTP:// version of a site to its HTTPS:// equivalent?
The most easy and clean solution I found was to
In SSL Settings -> require SSL
In Error Pages -> On 403.4 error -> Redirect to the HTTPS site
In Error Pages -> Edit Features Settings... -> Set Detailed errors for local requests and custom error pages for remote request
The benefit is that it requires no extra lines of code. Downside is that it redirects you to an absolute url.