Really? It’s semi-trivial in Catalyst and, to my knowledge but not experience, Mojolicious too. In Catalyst it’s just ensuring you only use uri_for or especially uri_for_action because it errors on non-existent dispatch paths (also uri_with) to construct all URIs. They are all relative to the app base in that case.

I'll freely admit that the most likely scenario is that I'm just dumb, and like I say its been a long time since I tried it, but re: uri_for and friends I feel like I remember it working but then my chains being busted because they choke on the prefix of the endpoint and/or other weird stuff. And OP has an example of stuff not working in Mojolicious in this very node, no?

So I've ended up with a convention (that at this point I've cargo-culted from myself), using OPs example, like:

 ProxyPass /rules http://localhost:3000/rules keepalive=On
 ProxyPassReverse /rules http://localhost:3000/rules
[download]

I didn’t even really read the OP. I don’t have apache running on my Mac at this point—just nginx—and I have little mojo experience and less taste for untangling deployment problems. I did just really read it and have an untested suggestion I think I’ll post.