Adapters
SSE
Integrate crossws with server-sent events.
If your deployment server is incapable of of handling WebSocket upgrades but support standard web API (Request and Response) you can integrate crossws to act as a one way (server to client) handler using server-sent events.
This is an experimental adapter and works only with a limited subset of crossws functionalities.
Instead of
WebSocket client you need to use EventSource as client to connect such server.import sseAdapter from "crossws/adapters/sse";
const sse = sseAdapter({
hooks: {
upgrade(request) {
// Handle upgrade logic
// You can return a custom response to abort
// You can return { headers } to override default headers
},
open(peer) {
// Use this hook to send messages to peer
peer.send("hello!");
},
},
});
Inside your Web compatible server handler:
async fetch(request) {
const url = new URL(request.url)
// Handle SSE
if (url.pathname === "/sse" && request.headers.get("accept") === "text/event-stream") {
return sse.fetch(request);
}
return new Response("server is up!")
}
In order to connect to the server, you need to use EventSource as client:
const ev = new EventSource("http://<server>/sse");
ev.addEventListener("message", (event) => {
console.log(event.data); // hello!
});
See
test/fixture/sse.ts for demo and src/adapters/sse.ts for implementation.