interface Deno.UpgradeWebSocketOptions

Sets the .protocol property on the client side web socket to the value provided here, which should be one of the strings specified in the protocols parameter when requesting the web socket. This is intended for clients and servers to specify sub-protocols to use to communicate to each other.

If the client does not respond to this frame with a pong within the timeout specified, the connection is deemed unhealthy and is closed. The close and error event will be emitted.

The unit is seconds, with a default of 30. Set to 0 to disable timeouts.

A node:net Socket from a node:http server's "upgrade" event. When provided, the WebSocket upgrade is performed over this existing TCP connection instead of through Deno.serve's built-in upgrade mechanism. The 101 Switching Protocols response is written automatically.

import http from "node:http";

const server = http.createServer();
server.on("upgrade", (req, socket, head) => {
  const { socket: ws } = Deno.upgradeWebSocket(
    new Request(`http://${req.headers.host}/`, {
      headers: req.headers as HeadersInit,
    }),
    { socket: socket as import("node:net").Socket, head },
  );
  ws.onmessage = (e) => ws.send(e.data);
});

Extra bytes already buffered by the HTTP parser that arrived with the upgrade request headers. This is the head Buffer from the node:http server's "upgrade" event and must be forwarded so those bytes are not lost.