ASGI applications can't send 101 Continue

[florimondmanca]

Hey there,

Thanks a lot for hopping onto this HTTPX extension.

I'm trying to integrate httpx-ws on florimondmanca/arel#31, where I'd like to test against an ASGI app using AsyncClient(app=...).

The confusing bit I'm having a hard time with, is httpx-ws seems to expect that the ASGI application under test returns the 101 Continue upgrade response. But this is generally done by ASGI servers. When a WebSocket request is received (on ws://), servers run the app with scope = {"type": "websocket", ...}. Applications catch this scope type and expect a websocket.connect message, then send websocket.accept, at which point the server sends the 101 Continue response and upgrades the connection.

This might also be why browsers require new WebSocket("ws://somewhere.org") -- how would they know if they should initiate a WebSocket handshake or a regular HTTP request if both use http://?

I'm unsure what should change at this point, as I haven't dived into the code yet, but mostly like that would be the ASGI implementation which should run the app as an ASGI server would? And use ws:// for URLs rather than http://?

[florimondmanca]

Oooh, answering the question for myself -- I forgot to use ASGIWebSocketTransport...

That is correctly covered in the docs: https://frankie567.github.io/httpx-ws/usage/asgi/

So, fine!

[frankie567]

Exactly! The transport implements the logic to "emulate" an ASGI server by executing your app and mapping ASGI messages to a HTTPX network stream.

Regarding the scheme, HTTPX currently only supports http/https, that's why I don't show examples with ws/wss. But Tom has recently implemented a change in httpcore to support them: encode/httpcore#625