From Mexico.purplecow.org
Handling Apache Reverse Proxy with Websockets
I first had to do this to take care of a Unifi instance.
RewriteEngine on RewriteCond %{HTTP:Upgrade} websocket [NC] RewriteCond %{HTTP:Connection} upgrade [NC] RewriteRule .* "wss://localhost:8443%{REQUEST_URI}" [P]
I'm sure I cribbed the base from somewhere, but I have no idea where it might have originally come from. I'm posting it here to save someone else the pain of digging around!