Bug Fixes

• remove the Partial modifier from the socket.data type (#4740) (e5c62ca)

Features

Support for WebTransport

The Socket.IO server can now use WebTransport as the underlying transport.

WebTransport is a web API that uses the HTTP/3 protocol as a bidirectional transport. It's intended for two-way communications between a web client and an HTTP/3 server.

References:

• https://w3c.github.io/webtransport/
• https://developer.mozilla.org/en-US/docs/Web/API/WebTransport
• https://developer.chrome.com/articles/webtransport/

Until WebTransport support lands in Node.js, you can use the @fails-components/webtransport package:

import { readFileSync } from "fs";
import { createServer } from "https";
import { Server } from "socket.io";
import { Http3Server } from "@fails-components/webtransport";

// WARNING: the total length of the validity period MUST NOT exceed two weeks (https://w3c.github.io/webtransport/#custom-certificate-requirements)
const cert = readFileSync("/path/to/my/cert.pem");
const key = readFileSync("/path/to/my/key.pem");

const httpsServer = createServer({
  key,
  cert
});

httpsServer.listen(3000);

const io = new Server(httpsServer, {
  transports: ["polling", "websocket", "webtransport"] // WebTransport is not enabled by default
});

const h3Server = new Http3Server({
  port: 3000,
  host: "0.0.0.0",
  secret: "changeit",
  cert,
  privKey: key,
});

(async () => {
  const stream = await h3Server.sessionStream("/socket.io/");
  const sessionReader = stream.getReader();

  while (true) {
    const { done, value } = await sessionReader.read();
    if (done) {
      break;
    }
    io.engine.onWebTransportSession(value);
  }
})();

h3Server.startServer();

Added in 123b68c.

Client bundles with CORS headers

The bundles will now have the right Access-Control-Allow-xxx headers.

Added in 63f181c.

Links

• Diff: https://github.com/socketio/socket.io/compare/4.6.2...4.7.0
• Client release: 4.7.0
• engine.io@~6.5.0 (diff)
• ws@~8.11.0 (no change)