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WebSocket transport does not allow healing connections #58
Description
In other words, the session does not allow the websocket to reopen after it closes - the session is immediately aborted.
A way to reproduce this is with using reconnecting-websocket or partysocket.
import { newWebSocketRpcSession } from "capnweb";
import { WebSocket as ReconnectingWebsocket } from "partysocket";
const sesssion = newWebSocketRpcSession(
new ReconnectingWebsocket("ws://localhost:8001/rpc")
);Is this intentional behaviour of the default websocket transport? If so, would a new ReconnectingWebsocket transport be acceptable or should this be left to userland? I'm not sure what your thoughts are about adding new transports to core.
Activity
kentonv commentedon Sep 27, 2025
Hmm, what are you imagining should happen to the session state on a reconnect? That is, what happens to stubs that were passed over the connection before the disconnect?
Possibilities include:
LoganDark commentedon Oct 17, 2025
I can't even tell when the WebSocket connection breaks. If I could, then I'd be able to call
newWebSocketRpcSessionagain, get a new stub, and do my own replay.I can listen to the WebSocket's
closeanderrorevents, but that doesn't catch all cases where the (private) transport calls#recievedError.I had to make my own transport for the server side (because of Bun), so it looks like I'll have to do that for the client too.
Edit: Looks like onRpcBroken can be used for this.
kentonv commentedon Oct 17, 2025
Yes, you can use
onRpcBroken()to detect when the connection is lost. And from that you should be able to implement various approaches to handling this.I could imagine having something more batteries-included, but it's not entirely clear what the behavior should be (see my previous comment).