Miniflare will always upgrade Web Socket connections. The Worker must respond
with a status 101 Switching Protocols response including a webSocket. For
example, the Worker below implements an echo WebSocket server:
export default {
fetch(request) {
const [client, server] = Object.values(new WebSocketPair());
server.accept();
server.addEventListener("message", (event) => {
server.send(event.data);
});
return new Response(null, {
status: 101,
webSocket: client,
});
},
};When using dispatchFetch, you are responsible for handling WebSockets by using
the webSocket property on Response. As an example, if the above worker
script was stored in echo.mjs:
import { Miniflare } from "miniflare";
const mf = new Miniflare({
modules: true,
scriptPath: "echo.mjs",
});
const res = await mf.dispatchFetch("https://example.com", {
headers: {
Upgrade: "websocket",
},
});
const webSocket = res.webSocket;
webSocket.accept();
webSocket.addEventListener("message", (event) => {
console.log(event.data);
});
webSocket.send("Hello!"); // Above listener logs "Hello!"