How to reverse proxy Websocket via Caddy using HTTPS outside and HTTP inside?

Question

Reverse proxying https://example.net to http://localhost:8080 works fine with Caddy reverse_proxy.

Reverse proxying ws://example.net to ws://localhost:8080 works also fine with Caddy reverse proxy.

But I do not know how to reverse proxy wss://example.net to ws://localhost:8080 with Caddy reversy proxy for enabling web sockets.

--

I have tried out the https://spring.io/guides/gs/messaging-stomp-websocket tutorial. It tells, how to use websockets with Spring Boot.

When I try it with localhost:8080, everything is fine.

When I run it on a webserver as localhost:8080, I have configured Caddy

example.net:80 {
 reverse_proxy localhost:8080
}

and I have configured app.js to the more generic brokerUrl '/gs-guide-websocket' (without the ws://localhost:8080).

it also works fine als http://example.net without TLS.

Now I tried to enable TLS and so I configured Caddy to

example.net {
 reverse_proxy localhost:8080
}

I want have it locally running via http://localhost:8080 using Caddy to bring this out to https://example.net .

With normal websites (without websockets), this works fine.

So when I try, the website https://example.net itself is loaded.

But the connection to Websocket fails:

WebSocket connection to 'wss://example.net/gs-guide-websocket' failed.

I want to achieve that wss://example.net/gs-guide-websocket is proxied to ws://localhost:8080/gs-guide-websocket.

How to make it working?

Answer 1

User ferrybig from caddy.community could help me:

https://caddy.community/t/reverse-proxy-to-websocket-does-not-work-via-https/33022/3

The solution is:

registry.addEndpoint("/gs-guide-websocket").setAllowedOrigins("https://example.net");