Has anyone tried to build an http4k proxy that sup...

# http4k

[Andrew O'Hara]

Has anyone tried to build an http4k proxy that supports websockets? I've done it before with Netty, but hoping I can continue to use http4k for this, since I don't need to support all of TCP this time.

[dave]

Never done it, but the setup is broadly the same with routers and filters and handlers, so i am pretty bullish that it might work.

If you come up with anything good, we can add it back into http4k-realtime-core 😉

[Andrew O'Hara]

My initial attempt shows the websocket can be established, but I suspect my server is failing to send follow-up frames from the client, despite switching my WS server's BodyMode to Stream. It's difficult to debug, because it's a blackbox client and server initiating the websocket, but I'm attempting to reproduce it in test.

On that note, assuming I've created a fake WsHandler, is it possible to convert it to an HttpHandler , so I can attach it as a fake device to my reverse-proxy? Or would I need to run my tests against running servers (via PolyServerConfig ) to accomplish this?

[dave]

no you can't convert between them - but you*should* be able to run it in memory without the server to unit test.

[Andrew O'Hara]

Well, I know I can connect a test client to an in-memory websocket, but the problem is that my fake reverse-proxy is supposed to have both regular http and websocket devices it can route to. I know I can do that by merging them into a PolyServerConfig and running a server. But I'm not sure how I can do that in-memory.

I might be making things confusing by the fact that there is both a fake reverse-proxy, and the reverse-proxy application under test. It's a reverse-proxy for several reverse-proxies 🙄 . The fake websocket server is a server behind the fake reverse-proxy, and my websocket client is connecting to the reverse proxy under test.

[Andrew O'Hara]

Untitled drawing (1).png

[dave]

You can't do that in memory I'm afraid. Each protocol "type" is a single distinct function and there isn't a combining function to test them all at once like that. That's why we combine them in the runtime later, so yes - you need the poly config

[Andrew O'Hara]

Got it. Thanks