chore(release): 4.7.2

Diff: https://github.com/socketio/socket.io/compare/4.7.1...4.7.2

.github/workflows/ci.yml

@@ -16,7 +16,9 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [12, 14, 16]
+        node-version:
+          - 16
+          - 20
 
     steps:
       - name: Checkout repository

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## 2023
 
+- [4.7.2](#472-2023-08-02) (Aug 2023)
+- [4.7.1](#471-2023-06-28) (Jun 2023)
+- [4.7.0](#470-2023-06-22) (Jun 2023)
+- [4.6.2](#462-2023-05-31) (May 2023)
 - [4.6.1](#461-2023-02-20) (Feb 2023)
 - [4.6.0](#460-2023-02-07) (Feb 2023)
 
@@ -57,6 +61,135 @@
 
 # Release notes
 
+## [4.7.2](https://github.com/socketio/socket.io/compare/4.7.1...4.7.2) (2023-08-02)
+
+
+### Bug Fixes
+
+* clean up child namespace when client is rejected in middleware ([#4773](https://github.com/socketio/socket.io/issues/4773)) ([0731c0d](https://github.com/socketio/socket.io/commit/0731c0d2f497d5cce596ea1ec32a67c08bcccbcd))
+* **webtransport:** properly handle WebTransport-only connections ([3468a19](https://github.com/socketio/socket.io/commit/3468a197afe87e65eb0d779fabd347fe683013ab))
+* **webtransport:** add proper framing ([a306db0](https://github.com/socketio/engine.io/commit/a306db09e8ddb367c7d62f45fec920f979580b7c))
+
+
+### Dependencies
+
+- [`engine.io@~6.5.2`](https://github.com/socketio/engine.io/releases/tag/6.5.2) ([diff](https://github.com/socketio/engine.io/compare/6.5.0...6.5.2))
+- [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) (no change)
+
+
+
+## [4.7.1](https://github.com/socketio/socket.io/compare/4.7.0...4.7.1) (2023-06-28)
+
+The client bundle contains a few fixes regarding the WebTransport support.
+
+### Dependencies
+
+- [`engine.io@~6.5.0`](https://github.com/socketio/engine.io/releases/tag/6.5.0) (no change)
+- [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) (no change)
+
+
+
+## [4.7.0](https://github.com/socketio/socket.io/compare/4.6.2...4.7.0) (2023-06-22)
+
+
+### Bug Fixes
+
+* remove the Partial modifier from the socket.data type ([#4740](https://github.com/socketio/socket.io/issues/4740)) ([e5c62ca](https://github.com/socketio/socket.io/commit/e5c62cad60fc7d16fbb024fd9be1d1880f4e6f5f))
+
+
+### 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](https://github.com/nodejs/node/issues/38478), you can use the `@fails-components/webtransport` package:
+
+```js
+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](https://github.com/socketio/engine.io/commit/123b68c04f9e971f59b526e0f967a488ee6b0116).
+
+
+#### Client bundles with CORS headers
+
+The bundles will now have the right `Access-Control-Allow-xxx` headers.
+
+Added in [63f181c](https://github.com/socketio/socket.io/commit/63f181cc12cbbbf94ed40eef52d60f36a1214fbe).
+
+
+### Dependencies
+
+- [`engine.io@~6.5.0`](https://github.com/socketio/engine.io/releases/tag/6.5.0) ([diff](https://github.com/socketio/engine.io/compare/6.4.2...6.5.0))
+- [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) (no change)
+
+
+
+## [4.6.2](https://github.com/socketio/socket.io/compare/4.6.1...4.6.2) (2023-05-31)
+
+
+### Bug Fixes
+
+* **exports:** move `types` condition to the top ([#4698](https://github.com/socketio/socket.io/issues/4698)) ([3d44aae](https://github.com/socketio/socket.io/commit/3d44aae381af38349fdb808d510d9f47a0c2507e))
+
+
+### Dependencies
+
+- [`engine.io@~6.4.2`](https://github.com/socketio/engine.io/releases/tag/6.4.0) ([diff](https://github.com/socketio/engine.io/compare/6.4.1...6.4.2))
+- [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) (no change)
+
+
+
 ## [4.6.1](https://github.com/socketio/socket.io/compare/4.6.0...4.6.1) (2023-02-20)
 
 
@@ -68,7 +201,7 @@
 
 ### Dependencies
 
-- [`engine.io@~6.4.0`](https://github.com/socketio/engine.io/releases/tag/6.4.0) (no change)
+- [`engine.io@~6.4.1`](https://github.com/socketio/engine.io/releases/tag/6.4.1) ([diff](https://github.com/socketio/engine.io/compare/6.4.0...6.4.1))
 - [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) (no change)
 
 
@@ -250,8 +383,8 @@ Added in [d0fd474](https://github.com/socketio/engine.io/commit/d0fd4746afa39629
 
 ### Dependencies
 
-- [`engine.io@~6.4.0`](https://github.com/socketio/engine.io/releases/tag/6.4.0) ([diff](https://github.com/socketio/engine.io/compare/6.2.0...6.2.1))
-- [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) ([diff](https://github.com/websockets/ws/compare/8.2.3...8.11.0))
+- [`engine.io@~6.4.0`](https://github.com/socketio/engine.io/releases/tag/6.4.0) (https://github.com/socketio/engine.io/compare/6.2.1...6.4.0)
+- [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) (https://github.com/websockets/ws/compare/8.2.3...8.11.0)
 
 
 ## [4.5.4](https://github.com/socketio/socket.io/compare/4.5.3...4.5.4) (2022-11-22)
@@ -276,6 +409,11 @@ This release contains a bump of:
 * **typings:** accept an HTTP2 server in the constructor ([d3d0a2d](https://github.com/socketio/socket.io/commit/d3d0a2d5beaff51fd145f810bcaf6914213f8a06))
 * **typings:** apply types to "io.timeout(...).emit()" calls ([e357daf](https://github.com/socketio/socket.io/commit/e357daf5858560bc84e7e50cd36f0278d6721ea1))
 
+### Dependencies
+
+- [`engine.io@~6.2.0`](https://github.com/socketio/engine.io/releases/tag/6.2.1) (no change)
+- [`ws@~8.2.3`](https://github.com/websockets/ws/releases/tag/8.2.3) (no change)
+
 
 
 ## [4.5.2](https://github.com/socketio/socket.io/compare/4.5.1...4.5.2) (2022-09-02)
@@ -286,13 +424,18 @@ This release contains a bump of:
 * prevent the socket from joining a room after disconnection ([18f3fda](https://github.com/socketio/socket.io/commit/18f3fdab12947a9fee3e9c37cfc1da97027d1473))
 * **uws:** prevent the server from crashing after upgrade ([ba497ee](https://github.com/socketio/socket.io/commit/ba497ee3eb52c4abf1464380d015d8c788714364))
 
+### Dependencies
+
+- [`engine.io@~6.2.0`](https://github.com/socketio/engine.io/releases/tag/6.2.0) (no change)
+- [`ws@~8.2.3`](https://github.com/websockets/ws/releases/tag/8.2.3) (no change)
+
 
 
 # [2.5.0](https://github.com/socketio/socket.io/compare/2.4.1...2.5.0) (2022-06-26)
 
 ⚠️ WARNING ⚠️
 
-The default value of the maxHttpBufferSize option has been decreased from 100 MB to 1 MB, in order to prevent attacks by denial of service.
+The default value of the `maxHttpBufferSize` option has been decreased from 100 MB to 1 MB, in order to prevent attacks by denial of service.
 
 Security advisory: [GHSA-j4f2-536g-r55m](https://github.com/advisories/GHSA-j4f2-536g-r55m)
 
@@ -304,6 +447,11 @@ Security advisory: [GHSA-j4f2-536g-r55m](https://github.com/advisories/GHSA-j4f2
 * only set 'connected' to true after middleware execution ([226cc16](https://github.com/socketio/socket.io/commit/226cc16165f9fe60f16ff4d295fb91c8971cde35))
 * prevent the socket from joining a room after disconnection ([f223178](https://github.com/socketio/socket.io/commit/f223178eb655a7713303b21a78f9ef9e161d6458))
 
+### Dependencies
+
+- [`engine.io@~3.6.0`](https://github.com/socketio/engine.io/releases/tag/3.6.0) (https://github.com/socketio/engine.io/compare/3.5.0...3.6.0)
+- [`ws@~7.4.2`](https://github.com/websockets/ws/releases/tag/7.4.2) (no change)
+
 
 
 ## [4.5.1](https://github.com/socketio/socket.io/compare/4.5.0...4.5.1) (2022-05-17)
@@ -314,6 +462,11 @@ Security advisory: [GHSA-j4f2-536g-r55m](https://github.com/advisories/GHSA-j4f2
 * forward the local flag to the adapter when using fetchSockets() ([30430f0](https://github.com/socketio/socket.io/commit/30430f0985f8e7c49394543d4c84913b6a15df60))
 * **typings:** add HTTPS server to accepted types ([#4351](https://github.com/socketio/socket.io/issues/4351)) ([9b43c91](https://github.com/socketio/socket.io/commit/9b43c9167cff817c60fa29dbda2ef7cd938aff51))
 
+### Dependencies
+
+- [`engine.io@~6.2.0`](https://github.com/socketio/engine.io/releases/tag/6.2.0) (no change)
+- [`ws@~8.2.3`](https://github.com/websockets/ws/releases/tag/8.2.3) (no change)
+
 
 
 # [4.5.0](https://github.com/socketio/socket.io/compare/4.4.1...4.5.0) (2022-04-23)
@@ -326,7 +479,7 @@ Security advisory: [GHSA-j4f2-536g-r55m](https://github.com/advisories/GHSA-j4f2
 
 ### Features
 
-* add support for catch-all listeners for outgoing packets ([531104d](https://github.com/socketio/socket.io/commit/531104d332690138b7aab84d5583d6204132c8b4))
+#### Catch-all listeners for outgoing packets
 
 This is similar to `onAny()`, but for outgoing packets.
 
@@ -338,7 +491,9 @@ socket.onAnyOutgoing((event, ...args) => {
 });
 ```
 
-* broadcast and expect multiple acks ([8b20457](https://github.com/socketio/socket.io/commit/8b204570a94979bbec307f23ca078f30f5cf07b0))
+Added in [531104d](https://github.com/socketio/socket.io/commit/531104d332690138b7aab84d5583d6204132c8b4).
+
+#### Broadcast and expect multiple acknowledgements
 
 Syntax:
 
@@ -348,18 +503,25 @@ io.timeout(1000).emit("some-event", (err, responses) => {
 });
 ```
 
-* add the "maxPayload" field in the handshake details ([088dcb4](https://github.com/socketio/engine.io/commit/088dcb4dff60df39785df13d0a33d3ceaa1dff38))
+Added in [8b20457](https://github.com/socketio/socket.io/commit/8b204570a94979bbec307f23ca078f30f5cf07b0).
 
-So that clients in HTTP long-polling can decide how many packets they have to send to stay under the maxHttpBufferSize
-value.
+#### `maxHttpBufferSize` value negotiation
 
-This is a backward compatible change which should not mandate a new major revision of the protocol (we stay in v4), as
-we only add a field in the JSON-encoded handshake data:
+A "maxPayload" field is now included in the Engine.IO handshake, so that clients in HTTP long-polling can decide how many packets they have to send to stay under the `maxHttpBufferSize` value.
+
+This is a backward compatible change which should not mandate a new major revision of the protocol (we stay in v4), as we only add a field in the JSON-encoded handshake data:
 
 ```
 0{"sid":"lv_VI97HAXpY6yYWAAAC","upgrades":["websocket"],"pingInterval":25000,"pingTimeout":5000,"maxPayload":1000000}
 ```
 
+Added in [088dcb4](https://github.com/socketio/engine.io/commit/088dcb4dff60df39785df13d0a33d3ceaa1dff38).
+
+### Dependencies
+
+- [`engine.io@~6.2.0`](https://github.com/socketio/engine.io/releases/tag/6.2.0) (https://github.com/socketio/engine.io/compare/6.1.0...6.2.0)
+- [`ws@~8.2.3`](https://github.com/websockets/ws/releases/tag/8.2.3) (no change)
+
 
 
 ## [4.4.1](https://github.com/socketio/socket.io/compare/4.4.0...4.4.1) (2022-01-06)

examples/basic-websocket-client/README.md

@@ -0,0 +1,18 @@
+# Basic Socket.IO client
+
+Please check the associated guide: https://socket.io/how-to/build-a-basic-client
+
+Content:
+
+```
+├── bundle
+│   └── socket.io.min.js
+├── src
+│   └── index.js
+├── test
+│   └── index.js
+├── check-bundle-size.js
+├── package.json
+├── README.md
+└── rollup.config.js
+```

examples/basic-websocket-client/bundle/socket.io.min.js

@@ -0,0 +1 @@
+class e{#e=new Map;on(e,t){let s=this.#e.get(e);s||this.#e.set(e,s=[]),s.push(t)}emit(e,...t){const s=this.#e.get(e);if(s)for(const e of s)e.apply(null,t)}}const t="0",s="1",n="2",i="3",o="4",r={CONNECT:0,DISCONNECT:1,EVENT:2};function c(){}class a extends e{id;connected=!1;#t;#s;#n;#i;#o;#r=[];#c;#a=!0;constructor(e,t){super(),this.#t=e,this.#s=Object.assign({path:"/socket.io/",reconnectionDelay:2e3},t),this.#h()}#h(){this.#n=new WebSocket(this.#u()),this.#n.onmessage=({data:e})=>this.#p(e),this.#n.onerror=c,this.#n.onclose=()=>this.#l("transport close")}#u(){return`${this.#t.replace(/^http/,"ws")}${this.#s.path}?EIO=4&transport=websocket`}#p(e){if("string"==typeof e)switch(e[0]){case t:this.#d(e);break;case s:this.#l("transport close");break;case n:this.#T(),this.#m(i);break;case o:let c;try{c=function(e){let t=1;const s={type:parseInt(e.charAt(t++),10)};e.charAt(t)&&(s.data=JSON.parse(e.substring(t)));if(!function(e){switch(e.type){case r.CONNECT:return"object"==typeof e.data;case r.DISCONNECT:return void 0===e.data;case r.EVENT:{const t=e.data;return Array.isArray(t)&&t.length>0&&"string"==typeof t[0]}default:return!1}}(s))throw new Error("invalid format");return s}(e)}catch(e){return this.#l("parse error")}this.#f(c);break;default:this.#l("parse error")}}#d(e){let t;try{t=JSON.parse(e.substring(1))}catch(e){return this.#l("parse error")}this.#o=t.pingInterval+t.pingTimeout,this.#T(),this.#C()}#f(e){switch(e.type){case r.CONNECT:this.#g(e);break;case r.DISCONNECT:this.#a=!1,this.#l("io server disconnect");break;case r.EVENT:super.emit.apply(this,e.data);break;default:this.#l("parse error")}}#g(e){this.id=e.data.sid,this.connected=!0,this.#r.forEach((e=>this.#y(e))),this.#r.slice(0),super.emit("connect")}#l(e){this.#n&&(this.#n.onclose=c,this.#n.close()),clearTimeout(this.#i),clearTimeout(this.#c),this.connected?(this.connected=!1,this.id=void 0,super.emit("disconnect",e)):super.emit("connect_error",e),this.#a&&(this.#c=setTimeout((()=>this.#h()),this.#s.reconnectionDelay))}#T(){clearTimeout(this.#i),this.#i=setTimeout((()=>{this.#l("ping timeout")}),this.#o)}#m(e){this.#n.readyState===WebSocket.OPEN&&this.#n.send(e)}#y(e){this.#m(o+function(e){let t=""+e.type;e.data&&(t+=JSON.stringify(e.data));return t}(e))}#C(){this.#y({type:r.CONNECT})}emit(...e){const t={type:r.EVENT,data:e};this.connected?this.#y(t):this.#r.push(t)}disconnect(){this.#a=!1,this.#l("io client disconnect")}}function h(e,t){return"string"!=typeof e&&(t=e,e=location.origin),new a(e,t)}export{h as io};

examples/basic-websocket-client/check-bundle-size.js

@@ -0,0 +1,17 @@
+import { rollup } from "rollup";
+import terser from "@rollup/plugin-terser";
+import { brotliCompressSync } from "node:zlib";
+
+const rollupBuild = await rollup({
+  input: "./src/index.js"
+});
+
+const rollupOutput = await rollupBuild.generate({
+  format: "esm",
+  plugins: [terser()],
+});
+
+const bundleAsString = rollupOutput.output[0].code;
+const brotliedBundle = brotliCompressSync(Buffer.from(bundleAsString));
+
+console.log(`Bundle size: ${brotliedBundle.length} B`);

examples/basic-websocket-client/package.json

@@ -0,0 +1,18 @@
+{
+  "type": "module",
+  "devDependencies": {
+    "@rollup/plugin-terser": "^0.4.0",
+    "chai": "^4.3.7",
+    "mocha": "^10.2.0",
+    "prettier": "^2.8.4",
+    "rollup": "^3.20.2",
+    "socket.io": "^4.6.1",
+    "ws": "^8.13.0"
+  },
+  "scripts": {
+    "bundle": "rollup -c",
+    "check-bundle-size": "node check-bundle-size.js",
+    "format": "prettier -w src/ test/",
+    "test": "mocha"
+  }
+}

examples/basic-websocket-client/rollup.config.js

@@ -0,0 +1,10 @@
+import terser from "@rollup/plugin-terser";
+
+export default {
+  input: "./src/index.js",
+  output: {
+    file: "./bundle/socket.io.min.js",
+    format: "esm",
+    plugins: [terser()],
+  }
+};

examples/basic-websocket-client/src/index.js

@@ -0,0 +1,273 @@
+class EventEmitter {
+  #listeners = new Map();
+
+  on(event, listener) {
+    let listeners = this.#listeners.get(event);
+    if (!listeners) {
+      this.#listeners.set(event, (listeners = []));
+    }
+    listeners.push(listener);
+  }
+
+  emit(event, ...args) {
+    const listeners = this.#listeners.get(event);
+    if (listeners) {
+      for (const listener of listeners) {
+        listener.apply(null, args);
+      }
+    }
+  }
+}
+
+const EIOPacketType = {
+  OPEN: "0",
+  CLOSE: "1",
+  PING: "2",
+  PONG: "3",
+  MESSAGE: "4",
+};
+
+const SIOPacketType = {
+  CONNECT: 0,
+  DISCONNECT: 1,
+  EVENT: 2,
+};
+
+function noop() {}
+
+class Socket extends EventEmitter {
+  id;
+  connected = false;
+
+  #uri;
+  #opts;
+  #ws;
+  #pingTimeoutTimer;
+  #pingTimeoutDelay;
+  #sendBuffer = [];
+  #reconnectTimer;
+  #shouldReconnect = true;
+
+  constructor(uri, opts) {
+    super();
+    this.#uri = uri;
+    this.#opts = Object.assign(
+      {
+        path: "/socket.io/",
+        reconnectionDelay: 2000,
+      },
+      opts
+    );
+    this.#open();
+  }
+
+  #open() {
+    this.#ws = new WebSocket(this.#createUrl());
+    this.#ws.onmessage = ({ data }) => this.#onMessage(data);
+    // dummy handler for Node.js
+    this.#ws.onerror = noop;
+    this.#ws.onclose = () => this.#onClose("transport close");
+  }
+
+  #createUrl() {
+    const uri = this.#uri.replace(/^http/, "ws");
+    const queryParams = "?EIO=4&transport=websocket";
+    return `${uri}${this.#opts.path}${queryParams}`;
+  }
+
+  #onMessage(data) {
+    if (typeof data !== "string") {
+      // TODO handle binary payloads
+      return;
+    }
+
+    switch (data[0]) {
+      case EIOPacketType.OPEN:
+        this.#onOpen(data);
+        break;
+
+      case EIOPacketType.CLOSE:
+        this.#onClose("transport close");
+        break;
+
+      case EIOPacketType.PING:
+        this.#resetPingTimeout();
+        this.#send(EIOPacketType.PONG);
+        break;
+
+      case EIOPacketType.MESSAGE:
+        let packet;
+        try {
+          packet = decode(data);
+        } catch (e) {
+          return this.#onClose("parse error");
+        }
+        this.#onPacket(packet);
+        break;
+
+      default:
+        this.#onClose("parse error");
+        break;
+    }
+  }
+
+  #onOpen(data) {
+    let handshake;
+    try {
+      handshake = JSON.parse(data.substring(1));
+    } catch (e) {
+      return this.#onClose("parse error");
+    }
+    this.#pingTimeoutDelay = handshake.pingInterval + handshake.pingTimeout;
+    this.#resetPingTimeout();
+    this.#doConnect();
+  }
+
+  #onPacket(packet) {
+    switch (packet.type) {
+      case SIOPacketType.CONNECT:
+        this.#onConnect(packet);
+        break;
+
+      case SIOPacketType.DISCONNECT:
+        this.#shouldReconnect = false;
+        this.#onClose("io server disconnect");
+        break;
+
+      case SIOPacketType.EVENT:
+        super.emit.apply(this, packet.data);
+        break;
+
+      default:
+        this.#onClose("parse error");
+        break;
+    }
+  }
+
+  #onConnect(packet) {
+    this.id = packet.data.sid;
+    this.connected = true;
+
+    this.#sendBuffer.forEach((packet) => this.#sendPacket(packet));
+    this.#sendBuffer.slice(0);
+
+    super.emit("connect");
+  }
+
+  #onClose(reason) {
+    if (this.#ws) {
+      this.#ws.onclose = noop;
+      this.#ws.close();
+    }
+
+    clearTimeout(this.#pingTimeoutTimer);
+    clearTimeout(this.#reconnectTimer);
+
+    if (this.connected) {
+      this.connected = false;
+      this.id = undefined;
+      super.emit("disconnect", reason);
+    } else {
+      super.emit("connect_error", reason);
+    }
+
+    if (this.#shouldReconnect) {
+      this.#reconnectTimer = setTimeout(
+        () => this.#open(),
+        this.#opts.reconnectionDelay
+      );
+    }
+  }
+
+  #resetPingTimeout() {
+    clearTimeout(this.#pingTimeoutTimer);
+    this.#pingTimeoutTimer = setTimeout(() => {
+      this.#onClose("ping timeout");
+    }, this.#pingTimeoutDelay);
+  }
+
+  #send(data) {
+    if (this.#ws.readyState === WebSocket.OPEN) {
+      this.#ws.send(data);
+    }
+  }
+
+  #sendPacket(packet) {
+    this.#send(EIOPacketType.MESSAGE + encode(packet));
+  }
+
+  #doConnect() {
+    this.#sendPacket({ type: SIOPacketType.CONNECT });
+  }
+
+  emit(...args) {
+    const packet = {
+      type: SIOPacketType.EVENT,
+      data: args,
+    };
+
+    if (this.connected) {
+      this.#sendPacket(packet);
+    } else {
+      this.#sendBuffer.push(packet);
+    }
+  }
+
+  disconnect() {
+    this.#shouldReconnect = false;
+    this.#onClose("io client disconnect");
+  }
+}
+
+function encode(packet) {
+  let output = "" + packet.type;
+
+  if (packet.data) {
+    output += JSON.stringify(packet.data);
+  }
+
+  return output;
+}
+
+function decode(data) {
+  let i = 1; // skip "4" prefix
+
+  const packet = {
+    type: parseInt(data.charAt(i++), 10),
+  };
+
+  if (data.charAt(i)) {
+    packet.data = JSON.parse(data.substring(i));
+  }
+
+  if (!isPacketValid(packet)) {
+    throw new Error("invalid format");
+  }
+
+  return packet;
+}
+
+function isPacketValid(packet) {
+  switch (packet.type) {
+    case SIOPacketType.CONNECT:
+      return typeof packet.data === "object";
+    case SIOPacketType.DISCONNECT:
+      return packet.data === undefined;
+    case SIOPacketType.EVENT: {
+      const args = packet.data;
+      return (
+        Array.isArray(args) && args.length > 0 && typeof args[0] === "string"
+      );
+    }
+    default:
+      return false;
+  }
+}
+
+export function io(uri, opts) {
+  if (typeof uri !== "string") {
+    opts = uri;
+    uri = location.origin;
+  }
+  return new Socket(uri, opts);
+}

examples/basic-websocket-client/test/index.js

@@ -0,0 +1,162 @@
+import { createServer } from "node:http";
+import { io as ioc } from "../src/index.js";
+import { WebSocket } from "ws";
+import { Server } from "socket.io";
+import { expect } from "chai";
+
+// @ts-ignore for Node.js
+globalThis.WebSocket = WebSocket;
+
+function waitFor(emitter, eventName) {
+  return new Promise((resolve) => {
+    emitter.on(eventName, resolve);
+  });
+}
+
+function sleep(delay) {
+  return new Promise((resolve) => {
+    setTimeout(resolve, delay);
+  });
+}
+
+describe("basic client", () => {
+  let io, port, socket;
+
+  beforeEach(() => {
+    const httpServer = createServer();
+    io = new Server(httpServer);
+
+    httpServer.listen(0);
+    port = httpServer.address().port;
+  });
+
+  afterEach(() => {
+    io.close();
+    socket.disconnect();
+  });
+
+  it("should connect", async () => {
+    socket = ioc(`ws://localhost:${port}`);
+
+    await waitFor(socket, "connect");
+
+    expect(socket.connected).to.eql(true);
+    expect(socket.id).to.be.a("string");
+  });
+
+  it("should connect with 'http://' scheme", async () => {
+    socket = ioc(`http://localhost:${port}`);
+
+    await waitFor(socket, "connect");
+  });
+
+  it("should connect with URL inferred from 'window.location'", async () => {
+    globalThis.location = {
+      origin: `http://localhost:${port}`,
+    };
+    socket = ioc();
+
+    await waitFor(socket, "connect");
+  });
+
+  it("should fail to connect to an invalid URL", async () => {
+    socket = ioc(`http://localhost:4321`);
+
+    await waitFor(socket, "connect_error");
+  });
+
+  it("should receive an event", async () => {
+    io.on("connection", (socket) => {
+      socket.emit("foo", 123);
+    });
+
+    socket = ioc(`ws://localhost:${port}`);
+
+    const value = await waitFor(socket, "foo");
+
+    expect(value).to.eql(123);
+  });
+
+  it("should send an event (not buffered)", async () => {
+    socket = ioc(`ws://localhost:${port}`);
+
+    const [serverSocket] = await Promise.all([
+      waitFor(io, "connection"),
+      waitFor(socket, "connect"),
+    ]);
+
+    socket.emit("foo", 456);
+
+    const value = await waitFor(serverSocket, "foo");
+
+    expect(value).to.eql(456);
+  });
+
+  it("should send an event (buffered)", async () => {
+    socket = ioc(`ws://localhost:${port}`);
+
+    socket.emit("foo", 789);
+
+    const [serverSocket] = await Promise.all([
+      waitFor(io, "connection"),
+      waitFor(socket, "connect"),
+    ]);
+
+    const value = await waitFor(serverSocket, "foo");
+
+    expect(value).to.eql(789);
+  });
+
+  it("should reconnect", async () => {
+    socket = ioc(`ws://localhost:${port}`, {
+      reconnectionDelay: 50,
+    });
+
+    await waitFor(socket, "connect");
+
+    io.close();
+
+    await waitFor(socket, "disconnect");
+
+    io.listen(port);
+
+    await waitFor(socket, "connect");
+  });
+
+  it("should respond to PING packets", async () => {
+    io.engine.opts.pingInterval = 50;
+    io.engine.opts.pingTimeout = 20;
+
+    socket = ioc(`ws://localhost:${port}`);
+
+    await waitFor(socket, "connect");
+
+    await sleep(500);
+
+    expect(socket.connected).to.eql(true);
+  });
+
+  it("should disconnect (client side)", async () => {
+    socket = ioc(`ws://localhost:${port}`);
+
+    await waitFor(socket, "connect");
+
+    socket.disconnect();
+
+    expect(socket.connected).to.eql(false);
+    expect(socket.id).to.eql(undefined);
+  });
+
+  it("should disconnect (server side)", async () => {
+    socket = ioc(`ws://localhost:${port}`);
+
+    const [serverSocket] = await Promise.all([
+      waitFor(io, "connection"),
+      waitFor(socket, "connect"),
+    ]);
+
+    serverSocket.disconnect();
+
+    await waitFor(socket, "disconnect");
+  });
+});

examples/cluster-haproxy/docker-compose.yml

@@ -1,51 +1,53 @@
+services:
+  haproxy:
+    image: haproxy:1.7-alpine
+    volumes:
+      - ./haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg:ro
+    links:
+      - server-john
+      - server-paul
+      - server-george
+      - server-ringo
+    ports:
+     - "3000:80"
 
-haproxy:
-  build: ./haproxy
-  links:
-    - server-john
-    - server-paul
-    - server-george
-    - server-ringo
-  ports:
-   - "3000:80"
+  server-john:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=John
 
-server-john:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=John
+  server-paul:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=Paul
 
-server-paul:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=Paul
+  server-george:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=George
 
-server-george:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=George
+  server-ringo:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=Ringo
 
-server-ringo:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=Ringo
-
-redis:
-  image: redis:alpine
-  expose:
-    - "6379"
+  redis:
+    image: redis:alpine
+    expose:
+      - "6379"

examples/cluster-haproxy/haproxy/Dockerfile

@@ -1,2 +0,0 @@
-FROM haproxy:1.7-alpine
-COPY haproxy.cfg /usr/local/etc/haproxy/haproxy.cfg

examples/cluster-httpd/docker-compose.yml

@@ -1,51 +1,53 @@
+services:
+  httpd:
+    image: httpd:2.4-alpine
+    volumes:
+      - ./httpd.conf:/usr/local/apache2/conf/httpd.conf:ro
+    links:
+      - server-john
+      - server-paul
+      - server-george
+      - server-ringo
+    ports:
+     - "3000:80"
 
-httpd:
-  build: ./httpd
-  links:
-    - server-john
-    - server-paul
-    - server-george
-    - server-ringo
-  ports:
-   - "3000:80"
+  server-john:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=John
 
-server-john:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=John
+  server-paul:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=Paul
 
-server-paul:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=Paul
+  server-george:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=George
 
-server-george:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=George
+  server-ringo:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=Ringo
 
-server-ringo:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=Ringo
-
-redis:
-  image: redis:alpine
-  expose:
-    - "6379"
+  redis:
+    image: redis:6
+    expose:
+      - "6379"

examples/cluster-httpd/httpd.conf

@@ -51,4 +51,5 @@ RewriteRule /(.*) balancer://nodes_ws/$1 [P,L]
 RewriteCond %{HTTP:Upgrade} !=websocket [NC]
 RewriteRule /(.*) balancer://nodes_polling/$1 [P,L]
 
-ProxyTimeout 3
+# must be bigger than pingInterval (25s by default) + pingTimeout (20s by default)
+ProxyTimeout 60

examples/cluster-httpd/httpd/Dockerfile

@@ -1,2 +0,0 @@
-FROM httpd:2.4-alpine
-COPY ./httpd.conf /usr/local/apache2/conf/httpd.conf

examples/cluster-httpd/server/Dockerfile

@@ -1,4 +1,4 @@
-FROM mhart/alpine-node:6
+FROM node:14-alpine
 
 # Create app directory
 RUN mkdir -p /usr/src/app

examples/cluster-nginx/docker-compose.yml

@@ -1,58 +1,58 @@
+services:
+  nginx:
+    image: nginx:alpine
+    volumes:
+      - ./nginx.conf:/etc/nginx/nginx.conf:ro
+    links:
+      - server-john
+      - server-paul
+      - server-george
+      - server-ringo
+    ports:
+     - "3000:80"
 
-nginx:
-  image: nginx:alpine
-  volumes:
-    - ./nginx.conf:/etc/nginx/nginx.conf:ro
-  links:
-    - server-john
-    - server-paul
-    - server-george
-    - server-ringo
-  ports:
-   - "3000:80"
+  server-john:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=John
 
-server-john:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=John
+  server-paul:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=Paul
 
-server-paul:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=Paul
+  server-george:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=George
 
-server-george:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=George
+  server-ringo:
+    build: ./server
+    links:
+      - redis
+    expose:
+      - "3000"
+    environment:
+      - NAME=Ringo
 
-server-ringo:
-  build: ./server
-  links:
-    - redis
-  expose:
-    - "3000"
-  environment:
-    - NAME=Ringo
+  client:
+    build: ./client
+    links:
+      - nginx
 
-client:
-  build: ./client
-  links:
-    - nginx
-
-redis:
-  image: redis:alpine
-  expose:
-    - "6379"
+  redis:
+    image: redis:6
+    expose:
+      - "6379"

examples/create-react-app-example/package.json

@@ -3,14 +3,14 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
-    "@testing-library/jest-dom": "^4.2.4",
-    "@testing-library/react": "^9.3.2",
-    "@testing-library/user-event": "^7.1.2",
-    "react": "^16.13.1",
-    "react-dom": "^16.13.1",
-    "react-scripts": "3.4.1",
-    "socket.io": "4",
-    "socket.io-client": "4"
+    "@testing-library/jest-dom": "^5.16.5",
+    "@testing-library/react": "^14.0.0",
+    "@testing-library/user-event": "^14.4.3",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "react-scripts": "^5.0.1",
+    "socket.io": "^4.6.1",
+    "socket.io-client": "^4.6.1"
   },
   "scripts": {
     "start": "react-scripts start",

examples/create-react-app-example/src/index.js

@@ -1,14 +1,15 @@
 import React from 'react';
-import ReactDOM from 'react-dom';
+import { createRoot } from 'react-dom/client';
 import './index.css';
 import App from './App';
 import * as serviceWorker from './serviceWorker';
 
-ReactDOM.render(
+const container = document.getElementById('root');
+const root = createRoot(container)
+root.render(
   <React.StrictMode>
     <App />
-  </React.StrictMode>,
-  document.getElementById('root')
+  </React.StrictMode>
 );
 
 // If you want your app to work offline and load faster, you can change

examples/private-messaging/package.json

@@ -8,18 +8,19 @@
     "lint": "vue-cli-service lint"
   },
   "dependencies": {
-    "core-js": "^3.6.5",
+    "core-js": "^3.8.3",
     "socket.io-client": "^4.0.0",
-    "vue": "^2.6.11"
+    "vue": "^2.6.14"
   },
   "devDependencies": {
-    "@vue/cli-plugin-babel": "~4.5.0",
-    "@vue/cli-plugin-eslint": "~4.5.0",
-    "@vue/cli-service": "~4.5.0",
-    "babel-eslint": "^10.1.0",
-    "eslint": "^6.7.2",
-    "eslint-plugin-vue": "^6.2.2",
-    "vue-template-compiler": "^2.6.11"
+    "@babel/core": "^7.12.16",
+    "@babel/eslint-parser": "^7.12.16",
+    "@vue/cli-plugin-babel": "~5.0.0",
+    "@vue/cli-plugin-eslint": "~5.0.0",
+    "@vue/cli-service": "~5.0.0",
+    "eslint": "^7.32.0",
+    "eslint-plugin-vue": "^8.0.3",
+    "vue-template-compiler": "^2.6.14"
   },
   "eslintConfig": {
     "root": true,
@@ -31,9 +32,11 @@
       "eslint:recommended"
     ],
     "parserOptions": {
-      "parser": "babel-eslint"
+      "parser": "@babel/eslint-parser"
     },
-    "rules": {}
+    "rules": {
+      "vue/multi-word-component-names": "off"
+    }
   },
   "browserslist": [
     "> 1%",

examples/private-messaging/src/App.vue

@@ -68,7 +68,7 @@ body {
 
 @font-face {
   font-family: Lato;
-  src: url("/fonts/Lato-Regular.ttf");
+  src: "~/public/fonts/Lato-Regular.ttf";
 }
 
 #app {

examples/webtransport/.gitignore

@@ -0,0 +1 @@
+*.pem

examples/webtransport/README.md

@@ -0,0 +1,18 @@
+
+# Socket.IO WebTransport example
+
+## How to use
+
+```shell
+# generate a self-signed certificate
+$ ./generate_cert.sh
+
+# install dependencies
+$ npm i
+
+# start the server
+$ node index.js
+
+# open a Chrome browser
+$ ./open_chrome.sh
+```

examples/webtransport/generate_cert.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+openssl req -new -x509 -nodes \
+    -out cert.pem \
+    -keyout key.pem \
+    -newkey ec \
+    -pkeyopt ec_paramgen_curve:prime256v1 \
+    -subj '/CN=127.0.0.1' \
+    -days 14

examples/webtransport/index.html

@@ -0,0 +1,35 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8">
+    <title>Socket.IO WebTransport exampleqg</title>
+  </head>
+  <body>
+    <script src="/socket.io/socket.io.js"></script>
+    <script>
+      const socket = io({
+        transportOptions: {
+          webtransport: {
+            hostname: "127.0.0.1"
+          }
+        }
+      });
+
+      socket.on("connect", () => {
+        console.log(`connect ${socket.id}`);
+
+        socket.io.engine.on("upgrade", (transport) => {
+          console.log(`transport upgraded to ${transport.name}`);
+        });
+      });
+
+      socket.on("connect_error", (err) => {
+        console.log(`connect_error due to ${err.message}`);
+      });
+
+      socket.on("disconnect", (reason) => {
+        console.log(`disconnect due to ${reason}`);
+      });
+    </script>
+  </body>
+</html>

examples/webtransport/index.js

@@ -0,0 +1,68 @@
+import { readFileSync } from "node:fs";
+import { createServer } from "node:https";
+import { Server } from "socket.io";
+import { Http3Server } from "@fails-components/webtransport";
+
+const key = readFileSync("./key.pem");
+const cert = readFileSync("./cert.pem");
+
+const httpsServer = createServer({
+  key,
+  cert
+}, (req, res) => {
+  if (req.method === "GET" && req.url === "/") {
+    const content = readFileSync("./index.html");
+    res.writeHead(200, {
+      "content-type": "text/html"
+    });
+    res.write(content);
+    res.end();
+  } else {
+    res.writeHead(404).end();
+  }
+});
+
+const io = new Server(httpsServer, {
+  transports: ["polling", "websocket", "webtransport"]
+});
+
+const port = process.env.PORT || 3000;
+
+io.on("connection", (socket) => {
+  console.log(`connect ${socket.id}`);
+
+  socket.conn.on("upgrade", (transport) => {
+    console.log(`transport upgraded to ${transport.name}`);
+  });
+
+  socket.on("disconnect", (reason) => {
+    console.log(`disconnect ${socket.id} due to ${reason}`);
+  });
+});
+
+httpsServer.listen(port, () => {
+  console.log(`server listening at https://localhost:${port}`);
+});
+
+const h3Server = new Http3Server({
+  port,
+  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();

examples/webtransport/open_chrome.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+HASH=`openssl x509 -pubkey -noout -in cert.pem |
+   openssl pkey -pubin -outform der |
+   openssl dgst -sha256 -binary |
+   base64`
+
+/opt/google/chrome/chrome \
+    --origin-to-force-quic-on=127.0.0.1:3000 \
+    --ignore-certificate-errors-spki-list=$HASH \
+    https://localhost:3000

examples/webtransport/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "webtransport",
+  "version": "0.0.1",
+  "description": "",
+  "private": true,
+  "type": "module",
+  "dependencies": {
+    "@fails-components/webtransport": "^0.1.7",
+    "socket.io": "^4.7.1"
+  }
+}

lib/index.ts

@@ -40,6 +40,7 @@ import {
   SecondArg,
 } from "./typed-events";
 import { patchAdapter, restoreAdapter, serveFile } from "./uws";
+import corsMiddleware from "cors";
 
 const debug = debugModule("socket.io:server");
 
@@ -202,6 +203,11 @@ export class Server<
    */
   _connectTimeout: number;
   private httpServer: http.Server | HTTPSServer | Http2SecureServer;
+  private _corsMiddleware: (
+    req: http.IncomingMessage,
+    res: http.ServerResponse,
+    next: () => void
+  ) => void;
 
   /**
    * Server constructor.
@@ -267,6 +273,10 @@ export class Server<
       this.attach(
         srv as http.Server | HTTPSServer | Http2SecureServer | number
       );
+
+    if (this.opts.cors) {
+      this._corsMiddleware = corsMiddleware(this.opts.cors);
+    }
   }
 
   get _opts() {
@@ -548,7 +558,13 @@ export class Server<
     srv.removeAllListeners("request");
     srv.on("request", (req, res) => {
       if (this.clientPathRegex.test(req.url!)) {
-        this.serve(req, res);
+        if (this._corsMiddleware) {
+          this._corsMiddleware(req, res, () => {
+            this.serve(req, res);
+          });
+        } else {
+          this.serve(req, res);
+        }
       } else {
         for (let i = 0; i < evs.length; i++) {
           evs[i].call(srv, req, res);

lib/socket.ts

@@ -202,7 +202,7 @@ export class Socket<
    * Additional information that can be attached to the Socket instance and which will be used in the
    * {@link Server.fetchSockets()} method.
    */
-  public data: Partial<SocketData> = {};
+  public data: SocketData = {} as SocketData;
   /**
    * Whether the socket is currently connected or not.
    *
@@ -260,7 +260,7 @@ export class Socket<
       this.id = previousSession.sid;
       this.pid = previousSession.pid;
       previousSession.rooms.forEach((room) => this.join(room));
-      this.data = previousSession.data as Partial<SocketData>;
+      this.data = previousSession.data as SocketData;
       previousSession.missedPackets.forEach((packet) => {
         this.packet({
           type: PacketType.EVENT,
@@ -280,6 +280,9 @@ export class Socket<
       }
     }
     this.handshake = this.buildHandshake(auth);
+
+    // prevents crash when the socket receives an "error" event without listener
+    this.on("error", noop);
   }
 
   /**
@@ -289,16 +292,16 @@ export class Socket<
    */
   private buildHandshake(auth: object): Handshake {
     return {
-      headers: this.request.headers,
+      headers: this.request?.headers || {},
       time: new Date() + "",
       address: this.conn.remoteAddress,
-      xdomain: !!this.request.headers.origin,
+      xdomain: !!this.request?.headers.origin,
       // @ts-ignore
-      secure: !!this.request.connection.encrypted,
+      secure: !this.request || !!this.request.connection.encrypted,
       issued: +new Date(),
-      url: this.request.url!,
+      url: this.request?.url!,
       // @ts-ignore
-      query: this.request._query,
+      query: this.request?._query || {},
       auth,
     };
   }
@@ -720,12 +723,11 @@ export class Socket<
    * @private
    */
   _onerror(err: Error): void {
-    if (this.listeners("error").length) {
-      this.emitReserved("error", err);
-    } else {
-      console.error("Missing error handler on `socket`.");
-      console.error(err.stack);
-    }
+    // FIXME the meaning of the "error" event is overloaded:
+    //  - it can be sent by the client (`socket.emit("error")`)
+    //  - it can be emitted when the connection encounters an error (an invalid packet for example)
+    //  - it can be emitted when a packet is rejected in a middleware (`socket.use()`)
+    this.emitReserved("error", err);
   }
 
   /**
@@ -756,7 +758,6 @@ export class Socket<
     }
 
     this._cleanup();
-    this.nsp._remove(this);
     this.client._remove(this);
     this.connected = false;
     this.emitReserved("disconnect", reason, description);
@@ -770,6 +771,7 @@ export class Socket<
    */
   _cleanup() {
     this.leaveAll();
+    this.nsp._remove(this);
     this.join = noop;
   }
 

package-lock.json

@@ -1,20 +1,21 @@
 {
   "name": "socket.io",
-  "version": "4.6.0",
+  "version": "4.7.1",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "socket.io",
-      "version": "4.6.0",
+      "version": "4.7.1",
       "license": "MIT",
       "dependencies": {
         "accepts": "~1.3.4",
         "base64id": "~2.0.0",
+        "cors": "~2.8.5",
         "debug": "~4.3.2",
-        "engine.io": "~6.4.1",
+        "engine.io": "~6.5.2",
         "socket.io-adapter": "~2.5.2",
-        "socket.io-parser": "~4.2.1"
+        "socket.io-parser": "~4.2.4"
       },
       "devDependencies": {
         "@types/mocha": "^9.0.0",
@@ -23,17 +24,17 @@
         "nyc": "^15.1.0",
         "prettier": "^2.3.2",
         "rimraf": "^3.0.2",
-        "socket.io-client": "4.6.1",
+        "socket.io-client": "4.7.2",
         "socket.io-client-v2": "npm:socket.io-client@^2.4.0",
         "superagent": "^8.0.0",
         "supertest": "^6.1.6",
         "ts-node": "^10.2.1",
         "tsd": "^0.21.0",
         "typescript": "^4.4.2",
-        "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.0.0"
+        "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.30.0"
       },
       "engines": {
-        "node": ">=10.0.0"
+        "node": ">=10.2.0"
       }
     },
     "node_modules/@ampproject/remapping": {
@@ -1228,9 +1229,9 @@
       }
     },
     "node_modules/cookiejar": {
-      "version": "2.1.3",
-      "resolved": "https://registry.npmjs.org/cookiejar/-/cookiejar-2.1.3.tgz",
-      "integrity": "sha512-JxbCBUdrfr6AQjOXrxoTvAMJO4HBTUIlBzslcJPAz+/KT8yk53fXun51u+RenNYvad/+Vc2DIz5o9UxlCDymFQ==",
+      "version": "2.1.4",
+      "resolved": "https://registry.npmjs.org/cookiejar/-/cookiejar-2.1.4.tgz",
+      "integrity": "sha512-LDx6oHrK+PhzLKJU9j5S7/Y3jM/mUHvD/DeI1WQmJn652iPC5Y4TBzC9l+5OMOXlyTTA+SmVUPm0HQUwpD5Jqw==",
       "dev": true
     },
     "node_modules/cors": {
@@ -1377,9 +1378,9 @@
       "dev": true
     },
     "node_modules/engine.io": {
-      "version": "6.4.1",
-      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-6.4.1.tgz",
-      "integrity": "sha512-JFYQurD/nbsA5BSPmbaOSLa3tSVj8L6o4srSwXXY3NqE+gGUNmmPTbhn8tjzcCtSqhFgIeqef81ngny8JM25hw==",
+      "version": "6.5.2",
+      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-6.5.2.tgz",
+      "integrity": "sha512-IXsMcGpw/xRfjra46sVZVHiSWo/nJ/3g1337q9KNXtS6YRzbW5yIzTCb9DjhrBe7r3GZQR0I4+nq+4ODk5g/cA==",
       "dependencies": {
         "@types/cookie": "^0.4.1",
         "@types/cors": "^2.8.12",
@@ -1389,30 +1390,30 @@
         "cookie": "~0.4.1",
         "cors": "~2.8.5",
         "debug": "~4.3.1",
-        "engine.io-parser": "~5.0.3",
+        "engine.io-parser": "~5.2.1",
         "ws": "~8.11.0"
       },
       "engines": {
-        "node": ">=10.0.0"
+        "node": ">=10.2.0"
       }
     },
     "node_modules/engine.io-client": {
-      "version": "6.4.0",
-      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-6.4.0.tgz",
-      "integrity": "sha512-GyKPDyoEha+XZ7iEqam49vz6auPnNJ9ZBfy89f+rMMas8AuiMWOZ9PVzu8xb9ZC6rafUqiGHSCfu22ih66E+1g==",
+      "version": "6.5.2",
+      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-6.5.2.tgz",
+      "integrity": "sha512-CQZqbrpEYnrpGqC07a9dJDz4gePZUgTPMU3NKJPSeQOyw27Tst4Pl3FemKoFGAlHzgZmKjoRmiJvbWfhCXUlIg==",
       "dev": true,
       "dependencies": {
         "@socket.io/component-emitter": "~3.1.0",
         "debug": "~4.3.1",
-        "engine.io-parser": "~5.0.3",
+        "engine.io-parser": "~5.2.1",
         "ws": "~8.11.0",
         "xmlhttprequest-ssl": "~2.0.0"
       }
     },
     "node_modules/engine.io-parser": {
-      "version": "5.0.4",
-      "resolved": "https://registry.npmjs.org/engine.io-parser/-/engine.io-parser-5.0.4.tgz",
-      "integrity": "sha512-+nVFp+5z1E3HcToEnO7ZIj3g+3k9389DvWtvJZz0T6/eOCPIyyxehFcedoYrZQrp0LgQbD9pPXhpMBKMd5QURg==",
+      "version": "5.2.1",
+      "resolved": "https://registry.npmjs.org/engine.io-parser/-/engine.io-parser-5.2.1.tgz",
+      "integrity": "sha512-9JktcM3u18nU9N2Lz3bWeBgxVgOKpw7yhRaoxQA3FUDZzzw+9WlA6p4G4u0RixNkg14fH7EfEc/RhpurtiROTQ==",
       "engines": {
         "node": ">=10.0.0"
       }
@@ -3463,15 +3464,15 @@
       }
     },
     "node_modules/socket.io-client": {
-      "version": "4.6.1",
-      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.6.1.tgz",
-      "integrity": "sha512-5UswCV6hpaRsNg5kkEHVcbBIXEYoVbMQaHJBXJCyEQ+CiFPV1NIOY0XOFWG4XR4GZcB8Kn6AsRs/9cy9TbqVMQ==",
+      "version": "4.7.2",
+      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.7.2.tgz",
+      "integrity": "sha512-vtA0uD4ibrYD793SOIAwlo8cj6haOeMHrGvwPxJsxH7CeIksqJ+3Zc06RvWTIFgiSqx4A3sOnTXpfAEE2Zyz6w==",
       "dev": true,
       "dependencies": {
         "@socket.io/component-emitter": "~3.1.0",
         "debug": "~4.3.2",
-        "engine.io-client": "~6.4.0",
-        "socket.io-parser": "~4.2.1"
+        "engine.io-client": "~6.5.2",
+        "socket.io-parser": "~4.2.4"
       },
       "engines": {
         "node": ">=10.0.0"
@@ -3586,9 +3587,9 @@
       }
     },
     "node_modules/socket.io-parser": {
-      "version": "4.2.2",
-      "resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-4.2.2.tgz",
-      "integrity": "sha512-DJtziuKypFkMMHCm2uIshOYC7QaylbtzQwiMYDuCKy3OPkjLzu4B2vAhTlqipRHHzrI0NJeBAizTK7X+6m1jVw==",
+      "version": "4.2.4",
+      "resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-4.2.4.tgz",
+      "integrity": "sha512-/GbIKmo8ioc+NIWIhwdecY0ge+qVBSMdgxGygevmdHj24bsfgtCmcUUcQ5ZzcylGFHsN3k4HB4Cgkl96KVnuew==",
       "dependencies": {
         "@socket.io/component-emitter": "~3.1.0",
         "debug": "~4.3.1"
@@ -4105,8 +4106,8 @@
       }
     },
     "node_modules/uWebSockets.js": {
-      "version": "20.0.0",
-      "resolved": "git+https://git@github.com/uNetworking/uWebSockets.js.git#4558ee00f9f1f686fffe1accbfc2e85b1af9c50f",
+      "version": "20.30.0",
+      "resolved": "git+https://git@github.com/uNetworking/uWebSockets.js.git#d39d4181daf5b670d44cbc1b18f8c28c85fd4142",
       "dev": true
     },
     "node_modules/v8-compile-cache-lib": {
@@ -5271,9 +5272,9 @@
       "integrity": "sha512-aSWTXFzaKWkvHO1Ny/s+ePFpvKsPnjc551iI41v3ny/ow6tBG5Vd+FuqGNhh1LxOmVzOlGUriIlOaokOvhaStA=="
     },
     "cookiejar": {
-      "version": "2.1.3",
-      "resolved": "https://registry.npmjs.org/cookiejar/-/cookiejar-2.1.3.tgz",
-      "integrity": "sha512-JxbCBUdrfr6AQjOXrxoTvAMJO4HBTUIlBzslcJPAz+/KT8yk53fXun51u+RenNYvad/+Vc2DIz5o9UxlCDymFQ==",
+      "version": "2.1.4",
+      "resolved": "https://registry.npmjs.org/cookiejar/-/cookiejar-2.1.4.tgz",
+      "integrity": "sha512-LDx6oHrK+PhzLKJU9j5S7/Y3jM/mUHvD/DeI1WQmJn652iPC5Y4TBzC9l+5OMOXlyTTA+SmVUPm0HQUwpD5Jqw==",
       "dev": true
     },
     "cors": {
@@ -5387,9 +5388,9 @@
       "dev": true
     },
     "engine.io": {
-      "version": "6.4.1",
-      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-6.4.1.tgz",
-      "integrity": "sha512-JFYQurD/nbsA5BSPmbaOSLa3tSVj8L6o4srSwXXY3NqE+gGUNmmPTbhn8tjzcCtSqhFgIeqef81ngny8JM25hw==",
+      "version": "6.5.2",
+      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-6.5.2.tgz",
+      "integrity": "sha512-IXsMcGpw/xRfjra46sVZVHiSWo/nJ/3g1337q9KNXtS6YRzbW5yIzTCb9DjhrBe7r3GZQR0I4+nq+4ODk5g/cA==",
       "requires": {
         "@types/cookie": "^0.4.1",
         "@types/cors": "^2.8.12",
@@ -5399,27 +5400,27 @@
         "cookie": "~0.4.1",
         "cors": "~2.8.5",
         "debug": "~4.3.1",
-        "engine.io-parser": "~5.0.3",
+        "engine.io-parser": "~5.2.1",
         "ws": "~8.11.0"
       }
     },
     "engine.io-client": {
-      "version": "6.4.0",
-      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-6.4.0.tgz",
-      "integrity": "sha512-GyKPDyoEha+XZ7iEqam49vz6auPnNJ9ZBfy89f+rMMas8AuiMWOZ9PVzu8xb9ZC6rafUqiGHSCfu22ih66E+1g==",
+      "version": "6.5.2",
+      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-6.5.2.tgz",
+      "integrity": "sha512-CQZqbrpEYnrpGqC07a9dJDz4gePZUgTPMU3NKJPSeQOyw27Tst4Pl3FemKoFGAlHzgZmKjoRmiJvbWfhCXUlIg==",
       "dev": true,
       "requires": {
         "@socket.io/component-emitter": "~3.1.0",
         "debug": "~4.3.1",
-        "engine.io-parser": "~5.0.3",
+        "engine.io-parser": "~5.2.1",
         "ws": "~8.11.0",
         "xmlhttprequest-ssl": "~2.0.0"
       }
     },
     "engine.io-parser": {
-      "version": "5.0.4",
-      "resolved": "https://registry.npmjs.org/engine.io-parser/-/engine.io-parser-5.0.4.tgz",
-      "integrity": "sha512-+nVFp+5z1E3HcToEnO7ZIj3g+3k9389DvWtvJZz0T6/eOCPIyyxehFcedoYrZQrp0LgQbD9pPXhpMBKMd5QURg=="
+      "version": "5.2.1",
+      "resolved": "https://registry.npmjs.org/engine.io-parser/-/engine.io-parser-5.2.1.tgz",
+      "integrity": "sha512-9JktcM3u18nU9N2Lz3bWeBgxVgOKpw7yhRaoxQA3FUDZzzw+9WlA6p4G4u0RixNkg14fH7EfEc/RhpurtiROTQ=="
     },
     "error-ex": {
       "version": "1.3.2",
@@ -6922,15 +6923,15 @@
       }
     },
     "socket.io-client": {
-      "version": "4.6.1",
-      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.6.1.tgz",
-      "integrity": "sha512-5UswCV6hpaRsNg5kkEHVcbBIXEYoVbMQaHJBXJCyEQ+CiFPV1NIOY0XOFWG4XR4GZcB8Kn6AsRs/9cy9TbqVMQ==",
+      "version": "4.7.2",
+      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.7.2.tgz",
+      "integrity": "sha512-vtA0uD4ibrYD793SOIAwlo8cj6haOeMHrGvwPxJsxH7CeIksqJ+3Zc06RvWTIFgiSqx4A3sOnTXpfAEE2Zyz6w==",
       "dev": true,
       "requires": {
         "@socket.io/component-emitter": "~3.1.0",
         "debug": "~4.3.2",
-        "engine.io-client": "~6.4.0",
-        "socket.io-parser": "~4.2.1"
+        "engine.io-client": "~6.5.2",
+        "socket.io-parser": "~4.2.4"
       }
     },
     "socket.io-client-v2": {
@@ -7026,9 +7027,9 @@
       }
     },
     "socket.io-parser": {
-      "version": "4.2.2",
-      "resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-4.2.2.tgz",
-      "integrity": "sha512-DJtziuKypFkMMHCm2uIshOYC7QaylbtzQwiMYDuCKy3OPkjLzu4B2vAhTlqipRHHzrI0NJeBAizTK7X+6m1jVw==",
+      "version": "4.2.4",
+      "resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-4.2.4.tgz",
+      "integrity": "sha512-/GbIKmo8ioc+NIWIhwdecY0ge+qVBSMdgxGygevmdHj24bsfgtCmcUUcQ5ZzcylGFHsN3k4HB4Cgkl96KVnuew==",
       "requires": {
         "@socket.io/component-emitter": "~3.1.0",
         "debug": "~4.3.1"
@@ -7402,9 +7403,9 @@
       "dev": true
     },
     "uWebSockets.js": {
-      "version": "git+https://git@github.com/uNetworking/uWebSockets.js.git#4558ee00f9f1f686fffe1accbfc2e85b1af9c50f",
+      "version": "git+https://git@github.com/uNetworking/uWebSockets.js.git#d39d4181daf5b670d44cbc1b18f8c28c85fd4142",
       "dev": true,
-      "from": "uWebSockets.js@github:uNetworking/uWebSockets.js#v20.0.0"
+      "from": "uWebSockets.js@github:uNetworking/uWebSockets.js#v20.30.0"
     },
     "v8-compile-cache-lib": {
       "version": "3.0.1",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "socket.io",
-  "version": "4.6.1",
+  "version": "4.7.2",
   "description": "node.js realtime framework server",
   "keywords": [
     "realtime",
@@ -26,9 +26,9 @@
   "type": "commonjs",
   "main": "./dist/index.js",
   "exports": {
+    "types": "./dist/index.d.ts",
     "import": "./wrapper.mjs",
-    "require": "./dist/index.js",
-    "types": "./dist/index.d.ts"
+    "require": "./dist/index.js"
   },
   "types": "./dist/index.d.ts",
   "license": "MIT",
@@ -48,10 +48,11 @@
   "dependencies": {
     "accepts": "~1.3.4",
     "base64id": "~2.0.0",
+    "cors": "~2.8.5",
     "debug": "~4.3.2",
-    "engine.io": "~6.4.1",
+    "engine.io": "~6.5.2",
     "socket.io-adapter": "~2.5.2",
-    "socket.io-parser": "~4.2.1"
+    "socket.io-parser": "~4.2.4"
   },
   "devDependencies": {
     "@types/mocha": "^9.0.0",
@@ -60,14 +61,14 @@
     "nyc": "^15.1.0",
     "prettier": "^2.3.2",
     "rimraf": "^3.0.2",
-    "socket.io-client": "4.6.1",
+    "socket.io-client": "4.7.2",
     "socket.io-client-v2": "npm:socket.io-client@^2.4.0",
     "superagent": "^8.0.0",
     "supertest": "^6.1.6",
     "ts-node": "^10.2.1",
     "tsd": "^0.21.0",
     "typescript": "^4.4.2",
-    "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.0.0"
+    "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.30.0"
   },
   "contributors": [
     {
@@ -88,7 +89,7 @@
     }
   ],
   "engines": {
-    "node": ">=10.0.0"
+    "node": ">=10.2.0"
   },
   "tsd": {
     "directory": "test"

test/namespaces.ts

@@ -653,6 +653,76 @@ describe("namespaces", () => {
       io.of(/^\/dynamic-\d+$/);
     });
 
+    it("should NOT clean up namespace when cleanupEmptyChildNamespaces is OFF and client is rejected in middleware", (done) => {
+      const io = new Server(0, { cleanupEmptyChildNamespaces: false });
+      io.of(/^\/dynamic-\d+$/).use((socket, next) => {
+        next(new Error("You shall not pass!"));
+      });
+      const c1 = createClient(io, "/dynamic-101");
+
+      c1.on("connect", () => {
+        done(new Error("Should not connect"));
+      });
+
+      c1.on("connect_error", () => {
+        setTimeout(() => {
+          expect(io._nsps.has("/dynamic-101")).to.be(true);
+          expect(io._nsps.get("/dynamic-101")!.sockets.size).to.be(0);
+          success(done, io, c1);
+        }, 100);
+      });
+    });
+
+    it("should clean up namespace when cleanupEmptyChildNamespaces is ON and client is rejected in middleware", (done) => {
+      const io = new Server(0, { cleanupEmptyChildNamespaces: true });
+      io.of(/^\/dynamic-\d+$/).use((socket, next) => {
+        next(new Error("You shall not pass!"));
+      });
+      const c1 = createClient(io, "/dynamic-101");
+
+      c1.on("connect", () => {
+        done(new Error("Should not connect"));
+      });
+
+      c1.on("connect_error", () => {
+        setTimeout(() => {
+          expect(io._nsps.has("/dynamic-101")).to.be(false);
+          success(done, io, c1);
+        }, 100);
+      });
+    });
+
+    it("should NOT clean up namespace when cleanupEmptyChildNamespaces is ON and client is rejected in middleware but there are other clients connected", (done) => {
+      const io = new Server(0, { cleanupEmptyChildNamespaces: true });
+      let clientIdxToReject = 0;
+      io.of(/^\/dynamic-\d+$/).use((socket, next) => {
+        if (clientIdxToReject) {
+          next(new Error("You shall not pass!"));
+        } else {
+          next();
+        }
+        clientIdxToReject++;
+      });
+      const c1 = createClient(io, "/dynamic-101");
+
+      c1.on("connect", () => {
+        const c2 = createClient(io, "/dynamic-101");
+        c2.on("connect", () => {
+          done(new Error("Client 2 should not connect"));
+        });
+        c2.on("connect_error", () => {
+          setTimeout(() => {
+            expect(io._nsps.has("/dynamic-101")).to.be(true);
+            expect(io._nsps.get("/dynamic-101")!.sockets.size).to.be(1);
+            success(done, io, c1, c2);
+          }, 100);
+        });
+      });
+      c1.on("connect_error", () => {
+        done(new Error("Client 1 should not get an error"));
+      });
+    });
+
     it("should attach a child namespace to its parent upon manual creation", () => {
       const io = new Server(0);
       const parentNamespace = io.of(/^\/dynamic-\d+$/);

test/server-attachment.ts

@@ -70,6 +70,27 @@ describe("server attachment", () => {
         });
     });
 
+    it("should serve client with necessary CORS headers", (done) => {
+      const srv = createServer();
+      new Server(srv, {
+        cors: {
+          origin: "https://good-origin.com",
+        },
+      });
+      request(srv)
+        .get("/socket.io/socket.io.js")
+        .set("origin", "https://good-origin.com")
+        .buffer(true)
+        .end((err, res) => {
+          if (err) return done(err);
+          expect(res.headers["access-control-allow-origin"]).to.be(
+            "https://good-origin.com"
+          );
+          expect(res.status).to.be(200);
+          done();
+        });
+    });
+
     it(
       "should serve bundle with msgpack parser",
       testSource("socket.io.msgpack.min.js")

test/socket.ts

@@ -684,6 +684,23 @@ describe("socket", () => {
     });
   });
 
+  it("should handshake a client without access to the Engine.IO request (WebTransport-only connection)", (done) => {
+    const io = new Server(0);
+    const clientSocket = createClient(io, "/");
+
+    io.engine.on("connection", (socket) => {
+      delete socket.request;
+    });
+
+    io.on("connection", (socket) => {
+      expect(socket.handshake.secure).to.be(true);
+      expect(socket.handshake.headers).to.eql({});
+      expect(socket.handshake.query).to.eql({});
+
+      success(done, io, clientSocket);
+    });
+  });
+
   it("should handle very large json", function (done) {
     this.timeout(30000);
     const io = new Server(0, { perMessageDeflate: false });
@@ -852,10 +869,6 @@ describe("socket", () => {
   it("should not crash when messing with Object prototype (and other globals)", (done) => {
     // @ts-ignore
     Object.prototype.foo = "bar";
-    // @ts-ignore
-    global.File = "";
-    // @ts-ignore
-    global.Blob = [];
     const io = new Server(0);
     const socket = createClient(io);