chore(release): 4.5.1

Diff: https://github.com/socketio/socket.io/compare/4.5.0...4.5.1

.github/ISSUE_TEMPLATE/bug_report.md

@@ -2,7 +2,7 @@
 name: Bug report
 about: Create a report to help us improve
 title: ''
-labels: 'bug'
+labels: 'to triage'
 assignees: ''
 
 ---

CHANGELOG.md

@@ -1,3 +1,85 @@
+## [4.5.1](https://github.com/socketio/socket.io/compare/4.5.0...4.5.1) (2022-05-17)
+
+
+### Bug Fixes
+
+* 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))
+
+
+
+# [4.5.0](https://github.com/socketio/socket.io/compare/4.4.1...4.5.0) (2022-04-23)
+
+
+### Bug Fixes
+
+* **typings:** ensure compatibility with TypeScript 3.x ([#4259](https://github.com/socketio/socket.io/issues/4259)) ([02c87a8](https://github.com/socketio/socket.io/commit/02c87a85614e217b8e7b93753f315790ae9d99f6))
+
+
+### Features
+
+* add support for catch-all listeners for outgoing packets ([531104d](https://github.com/socketio/socket.io/commit/531104d332690138b7aab84d5583d6204132c8b4))
+
+This is similar to `onAny()`, but for outgoing packets.
+
+Syntax:
+
+```js
+socket.onAnyOutgoing((event, ...args) => {
+  console.log(event);
+});
+```
+
+* broadcast and expect multiple acks ([8b20457](https://github.com/socketio/socket.io/commit/8b204570a94979bbec307f23ca078f30f5cf07b0))
+
+Syntax:
+
+```js
+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))
+
+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}
+```
+
+
+
+## [4.4.1](https://github.com/socketio/socket.io/compare/4.4.0...4.4.1) (2022-01-06)
+
+
+### Bug Fixes
+
+* **types:** make `RemoteSocket.data` type safe ([#4234](https://github.com/socketio/socket.io/issues/4234)) ([770ee59](https://github.com/socketio/socket.io/commit/770ee5949fb47c2556876c622f06c862573657d6))
+* **types:** pass `SocketData` type to custom namespaces ([#4233](https://github.com/socketio/socket.io/issues/4233)) ([f2b8de7](https://github.com/socketio/socket.io/commit/f2b8de71919e1b4d3e57f15a459972c1d1064787))
+
+
+
+# [4.4.0](https://github.com/socketio/socket.io/compare/4.3.2...4.4.0) (2021-11-18)
+
+
+### Bug Fixes
+
+* only set 'connected' to true after middleware execution ([02b0f73](https://github.com/socketio/socket.io/commit/02b0f73e2c64b09c72c5fbf7dc5f059557bdbe50))
+
+
+### Features
+
+* add an implementation based on uWebSockets.js ([c0d8c5a](https://github.com/socketio/socket.io/commit/c0d8c5ab234d0d2bef0d0dec472973cc9662f647))
+* add timeout feature ([f0ed42f](https://github.com/socketio/socket.io/commit/f0ed42f18cabef20ad976aeec37077b6bf3837a5))
+* add type information to `socket.data` ([#4159](https://github.com/socketio/socket.io/issues/4159)) ([fe8730c](https://github.com/socketio/socket.io/commit/fe8730ca0f15bc92d5de81cf934c89c76d6af329))
+
+
+
 ## [4.3.2](https://github.com/socketio/socket.io/compare/4.3.1...4.3.2) (2021-11-08)
 
 

Readme.md

@@ -2,8 +2,6 @@
 [![Run on Repl.it](https://repl.it/badge/github/socketio/socket.io)](https://replit.com/@socketio/socketio-minimal-example)
 [![Backers on Open Collective](https://opencollective.com/socketio/backers/badge.svg)](#backers) [![Sponsors on Open Collective](https://opencollective.com/socketio/sponsors/badge.svg)](#sponsors)
 [![Build Status](https://github.com/socketio/socket.io/workflows/CI/badge.svg)](https://github.com/socketio/socket.io/actions)
-[![Dependency Status](https://david-dm.org/socketio/socket.io.svg)](https://david-dm.org/socketio/socket.io)
-[![devDependency Status](https://david-dm.org/socketio/socket.io/dev-status.svg)](https://david-dm.org/socketio/socket.io#info=devDependencies)
 [![NPM version](https://badge.fury.io/js/socket.io.svg)](https://www.npmjs.com/package/socket.io)
 ![Downloads](https://img.shields.io/npm/dm/socket.io.svg?style=flat)
 [![](https://slackin-socketio.now.sh/badge.svg)](https://slackin-socketio.now.sh)
@@ -115,6 +113,14 @@ io.on('connection', client => { ... });
 io.listen(3000);
 ```
 
+### Module syntax 
+
+```js
+import { Server } from "socket.io";
+const io = new Server(server);
+io.listen(3000);
+```
+
 ### In conjunction with Express
 
 Starting with **3.0**, express applications have become request handler

examples/basic-crud-application/README.md

@@ -2,6 +2,13 @@
 
 Please read the related [guide](https://socket.io/get-started/basic-crud-application/).
 
+This repository contains several implementations of the server:
+
+| Directory                  | Language   | Database                                                                           | Cluster?                                                                                   |
+|----------------------------|------------|------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------|
+| `server/`                  | TypeScript | in-memory                                                                          | No                                                                                         |
+| `server-postgres-cluster/` | JavaScript | Postgres, with the [Postgres adapter](https://socket.io/docs/v4/postgres-adapter/) | Yes, with the [`@socket.io/sticky`](https://github.com/socketio/socket.io-sticky) module)  |
+
 ## Running the frontend
 
 ```

examples/basic-crud-application/angular-client/package.json

@@ -37,7 +37,7 @@
     "karma-chrome-launcher": "~3.1.0",
     "karma-coverage": "~2.0.3",
     "karma-jasmine": "~4.0.0",
-    "karma-jasmine-html-reporter": "^1.5.0",
+    "karma-jasmine-html-reporter": "~1.5.0",
     "protractor": "~7.0.0",
     "ts-node": "~8.3.0",
     "tslint": "~6.1.0",

examples/basic-crud-application/server-postgres-cluster/README.md

@@ -0,0 +1,16 @@
+
+A basic TODO project.
+
+| Characteristic |                                                                                           |
+|----------------|-------------------------------------------------------------------------------------------|
+| Language       | plain JavaScript                                                                          |
+| Database       | Postgres, with the [Postgres adapter](https://socket.io/docs/v4/postgres-adapter/)        |
+| Cluster?       | Yes, with the [`@socket.io/sticky`](https://github.com/socketio/socket.io-sticky) module) |
+
+## Usage
+
+```
+$ docker-compose up -d
+$ npm install
+$ npm start
+```

examples/basic-crud-application/server-postgres-cluster/docker-compose.yml

@@ -0,0 +1,9 @@
+version: "3"
+
+services:
+  postgres:
+    image: postgres:12
+    ports:
+      - "5432:5432"
+    environment:
+      POSTGRES_PASSWORD: "changeit"

examples/basic-crud-application/server-postgres-cluster/lib/app.js

@@ -0,0 +1,26 @@
+import { Server } from "socket.io";
+import createTodoHandlers from "./todo-management/todo.handlers.js";
+import { setupWorker } from "@socket.io/sticky";
+import { createAdapter } from "@socket.io/postgres-adapter";
+
+export function createApplication(httpServer, components, serverOptions = {}) {
+  const io = new Server(httpServer, serverOptions);
+
+  const { createTodo, readTodo, updateTodo, deleteTodo, listTodo } =
+    createTodoHandlers(components);
+
+  io.on("connection", (socket) => {
+    socket.on("todo:create", createTodo);
+    socket.on("todo:read", readTodo);
+    socket.on("todo:update", updateTodo);
+    socket.on("todo:delete", deleteTodo);
+    socket.on("todo:list", listTodo);
+  });
+
+  // enable sticky session in the cluster (to remove in standalone mode)
+  setupWorker(io);
+
+  io.adapter(createAdapter(components.connectionPool));
+
+  return io;
+}

examples/basic-crud-application/server-postgres-cluster/lib/cluster.js

@@ -0,0 +1,28 @@
+import cluster from "cluster";
+import { createServer } from "http";
+import { setupMaster } from "@socket.io/sticky";
+import { cpus } from "os";
+
+if (cluster.isMaster) {
+  console.log(`Master ${process.pid} is running`);
+  const httpServer = createServer();
+
+  setupMaster(httpServer, {
+    loadBalancingMethod: "least-connection",
+  });
+
+  httpServer.listen(3000);
+
+  for (let i = 0; i < cpus().length; i++) {
+    cluster.fork();
+  }
+
+  cluster.on("exit", (worker) => {
+    console.log(`Worker ${worker.process.pid} died`);
+    cluster.fork();
+  });
+} else {
+  console.log(`Worker ${process.pid} started`);
+
+  import("./index.js");
+}

examples/basic-crud-application/server-postgres-cluster/lib/index.js

@@ -0,0 +1,51 @@
+import { createServer } from "http";
+import { createApplication } from "./app.js";
+import { Sequelize } from "sequelize";
+import pg from "pg";
+import { PostgresTodoRepository } from "./todo-management/todo.repository.js";
+
+const httpServer = createServer();
+
+const sequelize = new Sequelize("postgres", "postgres", "changeit", {
+  dialect: "postgres",
+});
+
+const connectionPool = new pg.Pool({
+  user: "postgres",
+  host: "localhost",
+  database: "postgres",
+  password: "changeit",
+  port: 5432,
+});
+
+createApplication(
+  httpServer,
+  {
+    connectionPool,
+    todoRepository: new PostgresTodoRepository(sequelize),
+  },
+  {
+    cors: {
+      origin: ["http://localhost:4200"],
+    },
+  }
+);
+
+const main = async () => {
+  // create the tables if they do not exist already
+  await sequelize.sync();
+
+  // create the table needed by the postgres adapter
+  await connectionPool.query(`
+    CREATE TABLE IF NOT EXISTS socket_io_attachments (
+        id          bigserial UNIQUE,
+        created_at  timestamptz DEFAULT NOW(),
+        payload     bytea
+    );
+  `);
+
+  // uncomment when running in standalone mode
+  // httpServer.listen(3000);
+};
+
+main();

examples/basic-crud-application/server-postgres-cluster/lib/todo-management/todo.handlers.js

@@ -0,0 +1,140 @@
+import { Errors, mapErrorDetails, sanitizeErrorMessage } from "../util.js";
+import { v4 as uuid } from "uuid";
+import Joi from "joi";
+
+const idSchema = Joi.string().guid({
+  version: "uuidv4",
+});
+
+const todoSchema = Joi.object({
+  id: idSchema.alter({
+    create: (schema) => schema.forbidden(),
+    update: (schema) => schema.required(),
+  }),
+  title: Joi.string().max(256).required(),
+  completed: Joi.boolean().required(),
+});
+
+export default function (components) {
+  const { todoRepository } = components;
+  return {
+    createTodo: async function (payload, callback) {
+      const socket = this;
+
+      // validate the payload
+      const { error, value } = todoSchema.tailor("create").validate(payload, {
+        abortEarly: false,
+        stripUnknown: true,
+      });
+
+      if (error) {
+        return callback({
+          error: Errors.INVALID_PAYLOAD,
+          errorDetails: mapErrorDetails(error.details),
+        });
+      }
+
+      value.id = uuid();
+
+      // persist the entity
+      try {
+        await todoRepository.save(value);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      // acknowledge the creation
+      callback({
+        data: value.id,
+      });
+
+      // notify the other users
+      socket.broadcast.emit("todo:created", value);
+    },
+
+    readTodo: async function (id, callback) {
+      const { error } = idSchema.validate(id);
+
+      if (error) {
+        return callback({
+          error: Errors.ENTITY_NOT_FOUND,
+        });
+      }
+
+      try {
+        const todo = await todoRepository.findById(id);
+        callback({
+          data: todo,
+        });
+      } catch (e) {
+        callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+    },
+
+    updateTodo: async function (payload, callback) {
+      const socket = this;
+
+      const { error, value } = todoSchema.tailor("update").validate(payload, {
+        abortEarly: false,
+        stripUnknown: true,
+      });
+
+      if (error) {
+        return callback({
+          error: Errors.INVALID_PAYLOAD,
+          errorDetails: mapErrorDetails(error.details),
+        });
+      }
+
+      try {
+        await todoRepository.save(value);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      callback();
+      socket.broadcast.emit("todo:updated", value);
+    },
+
+    deleteTodo: async function (id, callback) {
+      const socket = this;
+
+      const { error } = idSchema.validate(id);
+
+      if (error) {
+        return callback({
+          error: Errors.ENTITY_NOT_FOUND,
+        });
+      }
+
+      try {
+        await todoRepository.deleteById(id);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      callback();
+      socket.broadcast.emit("todo:deleted", id);
+    },
+
+    listTodo: async function (callback) {
+      try {
+        callback({
+          data: await todoRepository.findAll(),
+        });
+      } catch (e) {
+        callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+    },
+  };
+}

examples/basic-crud-application/server-postgres-cluster/lib/todo-management/todo.repository.js

@@ -0,0 +1,74 @@
+import { Errors } from "../util.js";
+import { Model, DataTypes } from "sequelize";
+
+class CrudRepository {
+  findAll() {}
+  findById(id) {}
+  save(entity) {}
+  deleteById(id) {}
+}
+
+export class TodoRepository extends CrudRepository {}
+
+class Todo extends Model {}
+
+export class PostgresTodoRepository extends TodoRepository {
+  constructor(sequelize) {
+    super();
+    this.sequelize = sequelize;
+
+    Todo.init(
+      {
+        id: {
+          type: DataTypes.STRING,
+          primaryKey: true,
+          allowNull: false,
+        },
+        title: {
+          type: DataTypes.STRING,
+        },
+        completed: {
+          type: DataTypes.BOOLEAN,
+        },
+      },
+      {
+        sequelize,
+        tableName: "todos",
+      }
+    );
+  }
+
+  findAll() {
+    return this.sequelize.transaction((transaction) => {
+      return Todo.findAll({ transaction });
+    });
+  }
+
+  async findById(id) {
+    return this.sequelize.transaction(async (transaction) => {
+      const todo = await Todo.findByPk(id, { transaction });
+
+      if (!todo) {
+        throw Errors.ENTITY_NOT_FOUND;
+      }
+
+      return todo;
+    });
+  }
+
+  save(entity) {
+    return this.sequelize.transaction((transaction) => {
+      return Todo.upsert(entity, { transaction });
+    });
+  }
+
+  async deleteById(id) {
+    return this.sequelize.transaction(async (transaction) => {
+      const count = await Todo.destroy({ where: { id }, transaction });
+
+      if (count === 0) {
+        throw Errors.ENTITY_NOT_FOUND;
+      }
+    });
+  }
+}

examples/basic-crud-application/server-postgres-cluster/lib/util.js

@@ -0,0 +1,22 @@
+export const Errors = {
+  ENTITY_NOT_FOUND: "entity not found",
+  INVALID_PAYLOAD: "invalid payload",
+};
+
+const errorValues = Object.values(Errors);
+
+export function sanitizeErrorMessage(message) {
+  if (typeof message === "string" && errorValues.includes(message)) {
+    return message;
+  } else {
+    return "an unknown error has occurred";
+  }
+}
+
+export function mapErrorDetails(details) {
+  return details.map((item) => ({
+    message: item.message,
+    path: item.path,
+    type: item.type,
+  }));
+}

examples/basic-crud-application/server-postgres-cluster/package.json

@@ -0,0 +1,30 @@
+{
+  "name": "basic-crud-server",
+  "version": "0.0.1",
+  "description": "Server for the Basic CRUD Socket.IO example (with Postgres and multiple Socket.IO servers)",
+  "main": "lib/cluster.js",
+  "type": "module",
+  "scripts": {
+    "start": "node lib/cluster.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/socketio/socket.io.git"
+  },
+  "author": "Damien Arrachequesne <damien.arrachequesne@gmail.com>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/socketio/socket.io/issues"
+  },
+  "homepage": "https://github.com/socketio/socket.io#readme",
+  "dependencies": {
+    "@socket.io/postgres-adapter": "^0.2.0",
+    "@socket.io/sticky": "^1.0.1",
+    "joi": "^17.4.0",
+    "pg": "^8.7.3",
+    "pg-hstore": "^2.3.4",
+    "sequelize": "^6.18.0",
+    "socket.io": "^4.0.1",
+    "uuid": "^8.3.2"
+  }
+}

examples/basic-crud-application/server/lib/util.ts

@@ -7,8 +7,8 @@ export enum Errors {
 
 const errorValues: string[] = Object.values(Errors);
 
-export function sanitizeErrorMessage(message: string) {
-  if (errorValues.includes(message)) {
+export function sanitizeErrorMessage(message: any) {
+  if (typeof message === "string" && errorValues.includes(message)) {
     return message;
   } else {
     return "an unknown error has occurred";

examples/chat/README.md

@@ -6,7 +6,7 @@ A simple chat demo for Socket.IO
 ## How to use
 
 ```
-$ npm ci
+$ npm i
 $ npm start
 ```
 

examples/chat/public/main.js

@@ -264,14 +264,14 @@ $(function() {
     log('you have been disconnected');
   });
 
-  socket.on('reconnect', () => {
+  socket.io.on('reconnect', () => {
     log('you have been reconnected');
     if (username) {
       socket.emit('add user', username);
     }
   });
 
-  socket.on('reconnect_error', () => {
+  socket.io.on('reconnect_error', () => {
     log('attempt to reconnect has failed');
   });
 

examples/cluster-nginx/docker-compose.yml

@@ -1,6 +1,8 @@
 
 nginx:
-  build: ./nginx
+  image: nginx:alpine
+  volumes:
+    - ./nginx.conf:/etc/nginx/nginx.conf:ro
   links:
     - server-john
     - server-paul

examples/cluster-nginx/nginx/Dockerfile

@@ -1,3 +0,0 @@
-
-FROM nginx:alpine
-COPY nginx.conf /etc/nginx/nginx.conf

examples/cluster-nginx/server/index.js

@@ -1,15 +1,18 @@
-// Setup basic express server
-var express = require('express');
-var app = express();
-var server = require('http').createServer(app);
-var io = require('socket.io')(server);
-var redis = require('socket.io-redis');
-var port = process.env.PORT || 3000;
-var serverName = process.env.NAME || 'Unknown';
+const express = require('express');
+const app = express();
+const server = require('http').createServer(app);
+const io = require('socket.io')(server);
+const { createAdapter } = require('@socket.io/redis-adapter');
+const { createClient } = require('redis');
+const port = process.env.PORT || 3000;
+const serverName = process.env.NAME || 'Unknown';
 
-io.adapter(redis({ host: 'redis', port: 6379 }));
+const pubClient = createClient({ host: 'redis', port: 6379 });
+const subClient = pubClient.duplicate();
 
-server.listen(port, function () {
+io.adapter(createAdapter(pubClient, subClient));
+
+server.listen(port, () => {
   console.log('Server listening at port %d', port);
   console.log('Hello, I\'m %s, how can I help?', serverName);
 });
@@ -19,15 +22,15 @@ app.use(express.static(__dirname + '/public'));
 
 // Chatroom
 
-var numUsers = 0;
+let numUsers = 0;
 
-io.on('connection', function (socket) {
+io.on('connection', socket => {
   socket.emit('my-name-is', serverName);
 
-  var addedUser = false;
+  let addedUser = false;
 
   // when the client emits 'new message', this listens and executes
-  socket.on('new message', function (data) {
+  socket.on('new message', data => {
     // we tell the client to execute 'new message'
     socket.broadcast.emit('new message', {
       username: socket.username,
@@ -36,7 +39,7 @@ io.on('connection', function (socket) {
   });
 
   // when the client emits 'add user', this listens and executes
-  socket.on('add user', function (username) {
+  socket.on('add user', username => {
     if (addedUser) return;
 
     // we store the username in the socket session for this client
@@ -54,21 +57,21 @@ io.on('connection', function (socket) {
   });
 
   // when the client emits 'typing', we broadcast it to others
-  socket.on('typing', function () {
+  socket.on('typing', () => {
     socket.broadcast.emit('typing', {
       username: socket.username
     });
   });
 
   // when the client emits 'stop typing', we broadcast it to others
-  socket.on('stop typing', function () {
+  socket.on('stop typing', () => {
     socket.broadcast.emit('stop typing', {
       username: socket.username
     });
   });
 
   // when the user disconnects.. perform this
-  socket.on('disconnect', function () {
+  socket.on('disconnect', () => {
     if (addedUser) {
       --numUsers;
 

examples/cluster-nginx/server/package.json

@@ -7,9 +7,10 @@
   "private": true,
   "license": "MIT",
   "dependencies": {
+    "@socket.io/redis-adapter": "^7.0.1",
     "express": "4.13.4",
-    "socket.io": "^4.0.0",
-    "socket.io-redis": "^6.0.1"
+    "redis": "^3.1.2",
+    "socket.io": "^4.0.0"
   },
   "scripts": {
     "start": "node index.js"

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

@@ -1,4 +1,5 @@
 import React, { useState, useEffect } from 'react';
+import logo from './logo.svg';
 import './App.css';
 import io from 'socket.io-client';
 
@@ -23,7 +24,7 @@ function App() {
       socket.off('disconnect');
       socket.off('message');
     };
-  });
+  }, []);
 
   const sendMessage = () => {
     socket.emit('hello!');
@@ -32,9 +33,21 @@ function App() {
   return (
     <div className="App">
       <header className="App-header">
+        <img src={logo} className="App-logo" alt="logo" />
         <p>Connected: { '' + isConnected }</p>
         <p>Last message: { lastMessage || '-' }</p>
         <button onClick={ sendMessage }>Say hello!</button>
+        <p>
+          Edit <code>src/App.js</code> and save to reload.
+        </p>
+        <a
+          className="App-link"
+          href="https://reactjs.org"
+          target="_blank"
+          rel="noopener noreferrer"
+        >
+          Learn React
+        </a>
       </header>
     </div>
   );

examples/express-session-example/README.md

@@ -0,0 +1,16 @@
+# Example with [express-session](https://www.npmjs.com/package/express-session)
+
+This example shows how to share a session context between [Express](http://expressjs.com/) and [Socket.IO](https://socket.io/docs/v4/):
+
+![Video of the example](assets/demo.gif)
+
+Please read the related guide: https://socket.io/how-to/use-with-express-session
+
+## How to use
+
+```
+$ npm install
+$ npm start
+```
+
+And point your browser to `http://localhost:3000`. Optionally, specify a port by supplying the `PORT` env variable.

examples/express-session-example/index.html

@@ -0,0 +1,57 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Example with express-session</title>
+  </head>
+  <body>
+    <button onclick="incrementWithFetch()">Increment with fetch()</button>
+    <button onclick="logout()">Logout</button>
+    <p>Count: <span id="httpCount">0</span></p>
+
+    <button onclick="incrementWithEmit()">
+      Increment with Socket.IO emit()
+    </button>
+    <p>Status: <span id="ioStatus">disconnected</span></p>
+    <p>Count: <span id="ioCount">0</span></p>
+
+    <script src="/socket.io/socket.io.js"></script>
+    <script>
+      const httpCount = document.getElementById("httpCount");
+      const ioStatus = document.getElementById("ioStatus");
+      const ioCount = document.getElementById("ioCount");
+
+      const socket = io({
+        // with WebSocket only
+        // transports: ["websocket"],
+      });
+
+      async function incrementWithFetch() {
+        const response = await fetch("/incr", {
+          method: "post",
+        });
+        httpCount.innerText = await response.text();
+      }
+
+      function logout() {
+        fetch("/logout", {
+          method: "post",
+        });
+      }
+
+      async function incrementWithEmit() {
+        socket.emit("incr", (count) => {
+          ioCount.innerText = count;
+        });
+      }
+
+      socket.on("connect", () => {
+        ioStatus.innerText = "connected";
+      });
+
+      socket.on("disconnect", () => {
+        ioStatus.innerText = "disconnected";
+      });
+    </script>
+  </body>
+</html>

examples/express-session-example/index.js

@@ -0,0 +1,91 @@
+import express from "express";
+import { createServer } from "http";
+import { Server } from "socket.io";
+import session from "express-session";
+
+const port = process.env.PORT || 3000;
+
+const app = express();
+const httpServer = createServer(app);
+
+const sessionMiddleware = session({
+  secret: "changeit",
+  resave: true,
+  saveUninitialized: true,
+});
+
+app.use(sessionMiddleware);
+
+app.get("/", (req, res) => {
+  res.sendFile("./index.html", { root: process.cwd() });
+});
+
+app.post("/incr", (req, res) => {
+  const session = req.session;
+  session.count = (session.count || 0) + 1;
+  res.status(200).end("" + session.count);
+});
+
+app.post("/logout", (req, res) => {
+  const sessionId = req.session.id;
+  req.session.destroy(() => {
+    // disconnect all Socket.IO connections linked to this session ID
+    io.to(sessionId).disconnectSockets();
+    res.status(204).end();
+  });
+});
+
+const io = new Server(httpServer, {
+  allowRequest: (req, callback) => {
+    // with HTTP long-polling, we have access to the HTTP response here, but this is not
+    // the case with WebSocket, so we provide a dummy response object
+    const fakeRes = {
+      getHeader() {
+        return [];
+      },
+      setHeader(key, values) {
+        req.cookieHolder = values[0];
+      },
+      writeHead() {},
+    };
+    sessionMiddleware(req, fakeRes, () => {
+      if (req.session) {
+        // trigger the setHeader() above
+        fakeRes.writeHead();
+        // manually save the session (normally triggered by res.end())
+        req.session.save();
+      }
+      callback(null, true);
+    });
+  },
+});
+
+io.engine.on("initial_headers", (headers, req) => {
+  if (req.cookieHolder) {
+    headers["set-cookie"] = req.cookieHolder;
+    delete req.cookieHolder;
+  }
+});
+
+io.on("connect", (socket) => {
+  const req = socket.request;
+
+  socket.join(req.session.id);
+
+  socket.on("incr", (cb) => {
+    req.session.reload((err) => {
+      if (err) {
+        // session has expired
+        return socket.disconnect();
+      }
+      req.session.count = (req.session.count || 0) + 1;
+      req.session.save(() => {
+        cb(req.session.count);
+      });
+    });
+  });
+});
+
+httpServer.listen(port, () => {
+  console.log(`application is running at: http://localhost:${port}`);
+});

examples/express-session-example/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "express-session-example",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "description": "Example with express-session (https://github.com/expressjs/session)",
+  "scripts": {
+    "start": "node index.js"
+  },
+  "dependencies": {
+    "express": "~4.17.3",
+    "express-session": "~1.17.2",
+    "socket.io": "~4.4.1"
+  }
+}

examples/rollup-server-bundle/.gitignore

@@ -0,0 +1 @@
+bundle.js

examples/rollup-server-bundle/index.js

@@ -0,0 +1,3 @@
+import { Server } from "socket.io";
+
+new Server(0);

examples/rollup-server-bundle/package.json

@@ -0,0 +1,19 @@
+{
+  "name": "rollup-server-bundle",
+  "version": "0.0.1",
+  "description": "",
+  "main": "index.js",
+  "type": "module",
+  "author": "Damien Arrachequesne <damien.arrachequesne@gmail.com>",
+  "license": "ISC",
+  "scripts": {
+    "build": "rollup --config rollup.config.js"
+  },
+  "devDependencies": {
+    "@rollup/plugin-commonjs": "^21.0.3",
+    "@rollup/plugin-json": "^4.1.0",
+    "@rollup/plugin-node-resolve": "^13.1.3",
+    "rollup": "^2.70.1",
+    "socket.io": "^4.4.1"
+  }
+}

examples/rollup-server-bundle/rollup.config.js

@@ -0,0 +1,12 @@
+import resolve from "@rollup/plugin-node-resolve";
+import commonjs from "@rollup/plugin-commonjs";
+import json from "@rollup/plugin-json";
+
+export default {
+  input: "index.js",
+  output: {
+    file: "bundle.js",
+    format: "esm",
+  },
+  plugins: [resolve(), commonjs(), json({ compact: true })],
+};

examples/webpack-build/README.md

@@ -7,14 +7,5 @@ A sample Webpack build for the browser.
 
 ```
 $ npm i
-$ npm run build-all
+$ npm run build
 ```
-
-There are two WebPack configuration:
-
-- the minimal configuration, just bundling the application and its dependencies. The `app.js` file in the `dist` folder is the result of that build.
-
-- a slimmer one, where:
-  - the JSON polyfill needed for IE6/IE7 support has been removed.
-  - the `debug` calls and import have been removed (the [debug](https://github.com/visionmedia/debug) library is included in the build by default).
-  - the source has been uglified (dropping IE8 support), and an associated SourceMap has been generated.

examples/webpack-build/index.html

@@ -6,8 +6,7 @@
 </head>
 <body>
 
-  <!-- <script src="dist/app.js"></script> -->
-  <script src="dist/app.slim.js"></script>
+  <script src="dist/bundle.js"></script>
 
 </body>
-</html>
+</html>

examples/webpack-build/index.js

@@ -0,0 +1,15 @@
+import { io } from "socket.io-client";
+
+const socket = io("http://localhost:3000");
+
+socket.on("connect", () => {
+  console.log(`connect ${socket.id}`);
+});
+
+socket.on("connect_error", (err) => {
+  console.log(`connect_error due to ${err.message}`);
+});
+
+socket.on("disconnect", (reason) => {
+  console.log(`disconnect due to ${reason}`);
+});

examples/webpack-build/lib/index.js

@@ -1,12 +0,0 @@
-
-import io from 'socket.io-client';
-
-const socket = io('http://localhost:3000');
-
-console.log('init');
-
-socket.on('connect', onConnect);
-
-function onConnect(){
-  console.log('connect ' + socket.id);
-}

examples/webpack-build/package.json

@@ -2,20 +2,15 @@
   "name": "webpack-build",
   "version": "1.0.0",
   "description": "A sample Webpack build",
+  "type": "module",
   "scripts": {
-    "build": "webpack --config ./support/webpack.config.js",
-    "build-slim": "webpack --config ./support/webpack.config.slim.js",
-    "build-json-parser": "webpack --config ./support/webpack.config.json-parser.js",
-    "build-all": "npm run build && npm run build-slim && npm run build-json-parser"
+    "build": "webpack"
   },
   "author": "Damien Arrachequesne",
   "license": "MIT",
   "dependencies": {
-    "socket.io-client": "^2.0.2",
-    "socket.io-json-parser": "^2.1.0"
-  },
-  "devDependencies": {
-    "strip-loader": "^0.1.2",
-    "webpack": "^2.6.1"
+    "socket.io-client": "^4.4.1",
+    "webpack": "^5.72.0",
+    "webpack-cli": "^4.9.2"
   }
 }

examples/webpack-build/support/noop.js

@@ -1,2 +0,0 @@
-
-module.exports = function () { return function () {}; };

examples/webpack-build/support/webpack.config.js

@@ -1,8 +0,0 @@
-
-module.exports = {
-  entry: './lib/index.js',
-  output: {
-    path: require('path').join(__dirname, '../dist'),
-    filename: 'app.js'
-  }
-};

examples/webpack-build/support/webpack.config.json-parser.js

@@ -1,33 +0,0 @@
-
-var webpack = require('webpack');
-
-module.exports = {
-  entry: './lib/index.js',
-  output: {
-    path: require('path').join(__dirname, '../dist'),
-    filename: 'app.json-parser.js'
-  },
-  // generate sourcemap
-  devtool: 'source-map',
-  plugins: [
-    // replace require('debug')() with an noop function
-    new webpack.NormalModuleReplacementPlugin(/debug/, process.cwd() + '/support/noop.js'),
-    // replace socket.io-parser with socket.io-json-parser
-    new webpack.NormalModuleReplacementPlugin(/socket\.io-parser/, 'socket.io-json-parser'),
-    // use uglifyJS (IE9+ support)
-    new webpack.optimize.UglifyJsPlugin({
-      compress: {
-        warnings: false
-      }
-    })
-  ],
-  module: {
-    loaders: [
-      {
-        // strip `debug()` calls
-        test: /\.js$/,
-        loader: 'strip-loader?strip[]=debug'
-      }
-    ]
-  }
-};

examples/webpack-build/support/webpack.config.slim.js

@@ -1,31 +0,0 @@
-
-var webpack = require('webpack');
-
-module.exports = {
-  entry: './lib/index.js',
-  output: {
-    path: require('path').join(__dirname, '../dist'),
-    filename: 'app.slim.js'
-  },
-  // generate sourcemap
-  devtool: 'source-map',
-  plugins: [
-    // replace require('debug')() with an noop function
-    new webpack.NormalModuleReplacementPlugin(/debug/, process.cwd() + '/support/noop.js'),
-    // use uglifyJS (IE9+ support)
-    new webpack.optimize.UglifyJsPlugin({
-      compress: {
-        warnings: false
-      }
-    })
-  ],
-  module: {
-    loaders: [
-      {
-        // strip `debug()` calls
-        test: /\.js$/,
-        loader: 'strip-loader?strip[]=debug'
-      }
-    ]
-  }
-};

examples/webpack-build/webpack.config.js

@@ -0,0 +1,7 @@
+export default {
+  entry: "./index.js",
+  mode: "production",
+  output: {
+    filename: "bundle.js",
+  },
+};

lib/broadcast-operator.ts

@@ -9,7 +9,7 @@ import type {
   TypedEventBroadcaster,
 } from "./typed-events";
 
-export class BroadcastOperator<EmitEvents extends EventsMap>
+export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   implements TypedEventBroadcaster<EmitEvents>
 {
   constructor(
@@ -26,7 +26,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
    * @return a new BroadcastOperator instance
    * @public
    */
-  public to(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public to(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
     const rooms = new Set(this.rooms);
     if (Array.isArray(room)) {
       room.forEach((r) => rooms.add(r));
@@ -48,7 +48,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
    * @return a new BroadcastOperator instance
    * @public
    */
-  public in(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public in(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
     return this.to(room);
   }
 
@@ -59,7 +59,9 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
    * @return a new BroadcastOperator instance
    * @public
    */
-  public except(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public except(
+    room: Room | Room[]
+  ): BroadcastOperator<EmitEvents, SocketData> {
     const exceptRooms = new Set(this.exceptRooms);
     if (Array.isArray(room)) {
       room.forEach((r) => exceptRooms.add(r));
@@ -81,7 +83,9 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
    * @return a new BroadcastOperator instance
    * @public
    */
-  public compress(compress: boolean): BroadcastOperator<EmitEvents> {
+  public compress(
+    compress: boolean
+  ): BroadcastOperator<EmitEvents, SocketData> {
     const flags = Object.assign({}, this.flags, { compress });
     return new BroadcastOperator(
       this.adapter,
@@ -99,7 +103,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
    * @return a new BroadcastOperator instance
    * @public
    */
-  public get volatile(): BroadcastOperator<EmitEvents> {
+  public get volatile(): BroadcastOperator<EmitEvents, SocketData> {
     const flags = Object.assign({}, this.flags, { volatile: true });
     return new BroadcastOperator(
       this.adapter,
@@ -115,7 +119,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
    * @return a new BroadcastOperator instance
    * @public
    */
-  public get local(): BroadcastOperator<EmitEvents> {
+  public get local(): BroadcastOperator<EmitEvents, SocketData> {
     const flags = Object.assign({}, this.flags, { local: true });
     return new BroadcastOperator(
       this.adapter,
@@ -125,6 +129,29 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
     );
   }
 
+  /**
+   * Adds a timeout in milliseconds for the next operation
+   *
+   * <pre><code>
+   *
+   * io.timeout(1000).emit("some-event", (err, responses) => {
+   *   // ...
+   * });
+   *
+   * </pre></code>
+   *
+   * @param timeout
+   */
+  public timeout(timeout: number) {
+    const flags = Object.assign({}, this.flags, { timeout });
+    return new BroadcastOperator(
+      this.adapter,
+      this.rooms,
+      this.exceptRooms,
+      flags
+    );
+  }
+
   /**
    * Emits to all clients.
    *
@@ -145,14 +172,65 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
       data: data,
     };
 
-    if ("function" == typeof data[data.length - 1]) {
-      throw new Error("Callbacks are not supported when broadcasting");
+    const withAck = typeof data[data.length - 1] === "function";
+
+    if (!withAck) {
+      this.adapter.broadcast(packet, {
+        rooms: this.rooms,
+        except: this.exceptRooms,
+        flags: this.flags,
+      });
+
+      return true;
     }
 
-    this.adapter.broadcast(packet, {
-      rooms: this.rooms,
-      except: this.exceptRooms,
-      flags: this.flags,
+    const ack = data.pop() as (...args: any[]) => void;
+    let timedOut = false;
+    let responses: any[] = [];
+
+    const timer = setTimeout(() => {
+      timedOut = true;
+      ack.apply(this, [new Error("operation has timed out"), responses]);
+    }, this.flags.timeout);
+
+    let expectedServerCount = -1;
+    let actualServerCount = 0;
+    let expectedClientCount = 0;
+
+    const checkCompleteness = () => {
+      if (
+        !timedOut &&
+        expectedServerCount === actualServerCount &&
+        responses.length === expectedClientCount
+      ) {
+        clearTimeout(timer);
+        ack.apply(this, [null, responses]);
+      }
+    };
+
+    this.adapter.broadcastWithAck(
+      packet,
+      {
+        rooms: this.rooms,
+        except: this.exceptRooms,
+        flags: this.flags,
+      },
+      (clientCount) => {
+        // each Socket.IO server in the cluster sends the number of clients that were notified
+        expectedClientCount += clientCount;
+        actualServerCount++;
+        checkCompleteness();
+      },
+      (clientResponse) => {
+        // each client sends an acknowledgement
+        responses.push(clientResponse);
+        checkCompleteness();
+      }
+    );
+
+    this.adapter.serverCount().then((serverCount) => {
+      expectedServerCount = serverCount;
+      checkCompleteness();
     });
 
     return true;
@@ -177,19 +255,25 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
    *
    * @public
    */
-  public fetchSockets(): Promise<RemoteSocket<EmitEvents>[]> {
+  public fetchSockets<SocketData = any>(): Promise<
+    RemoteSocket<EmitEvents, SocketData>[]
+  > {
     return this.adapter
       .fetchSockets({
         rooms: this.rooms,
         except: this.exceptRooms,
+        flags: this.flags,
       })
       .then((sockets) => {
         return sockets.map((socket) => {
           if (socket instanceof Socket) {
             // FIXME the TypeScript compiler complains about missing private properties
-            return socket as unknown as RemoteSocket<EmitEvents>;
+            return socket as unknown as RemoteSocket<EmitEvents, SocketData>;
           } else {
-            return new RemoteSocket(this.adapter, socket as SocketDetails);
+            return new RemoteSocket(
+              this.adapter,
+              socket as SocketDetails<SocketData>
+            );
           }
         });
       });
@@ -206,6 +290,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
       {
         rooms: this.rooms,
         except: this.exceptRooms,
+        flags: this.flags,
       },
       Array.isArray(room) ? room : [room]
     );
@@ -222,6 +307,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
       {
         rooms: this.rooms,
         except: this.exceptRooms,
+        flags: this.flags,
       },
       Array.isArray(room) ? room : [room]
     );
@@ -238,6 +324,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
       {
         rooms: this.rooms,
         except: this.exceptRooms,
+        flags: this.flags,
       },
       close
     );
@@ -247,27 +334,27 @@ export class BroadcastOperator<EmitEvents extends EventsMap>
 /**
  * Format of the data when the Socket instance exists on another Socket.IO server
  */
-interface SocketDetails {
+interface SocketDetails<SocketData> {
   id: SocketId;
   handshake: Handshake;
   rooms: Room[];
-  data: any;
+  data: SocketData;
 }
 
 /**
  * Expose of subset of the attributes and methods of the Socket class
  */
-export class RemoteSocket<EmitEvents extends EventsMap>
+export class RemoteSocket<EmitEvents extends EventsMap, SocketData>
   implements TypedEventBroadcaster<EmitEvents>
 {
   public readonly id: SocketId;
   public readonly handshake: Handshake;
   public readonly rooms: Set<Room>;
-  public readonly data: any;
+  public readonly data: SocketData;
 
-  private readonly operator: BroadcastOperator<EmitEvents>;
+  private readonly operator: BroadcastOperator<EmitEvents, SocketData>;
 
-  constructor(adapter: Adapter, details: SocketDetails) {
+  constructor(adapter: Adapter, details: SocketDetails<SocketData>) {
     this.id = details.id;
     this.handshake = details.handshake;
     this.rooms = new Set(details.rooms);

lib/client.ts

@@ -21,21 +21,27 @@ interface WriteOptions {
 export class Client<
   ListenEvents extends EventsMap,
   EmitEvents extends EventsMap,
-  ServerSideEvents extends EventsMap
+  ServerSideEvents extends EventsMap,
+  SocketData = any
 > {
   public readonly conn: RawSocket;
 
   private readonly id: string;
-  private readonly server: Server<ListenEvents, EmitEvents, ServerSideEvents>;
+  private readonly server: Server<
+    ListenEvents,
+    EmitEvents,
+    ServerSideEvents,
+    SocketData
+  >;
   private readonly encoder: Encoder;
   private readonly decoder: Decoder;
   private sockets: Map<
     SocketId,
-    Socket<ListenEvents, EmitEvents, ServerSideEvents>
+    Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
   > = new Map();
   private nsps: Map<
     string,
-    Socket<ListenEvents, EmitEvents, ServerSideEvents>
+    Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
   > = new Map();
   private connectTimeout?: NodeJS.Timeout;
 
@@ -47,7 +53,7 @@ export class Client<
    * @package
    */
   constructor(
-    server: Server<ListenEvents, EmitEvents, ServerSideEvents>,
+    server: Server<ListenEvents, EmitEvents, ServerSideEvents, SocketData>,
     conn: any
   ) {
     this.server = server;
@@ -112,7 +118,7 @@ export class Client<
       auth,
       (
         dynamicNspName:
-          | Namespace<ListenEvents, EmitEvents, ServerSideEvents>
+          | Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
           | false
       ) => {
         if (dynamicNspName) {
@@ -171,7 +177,9 @@ export class Client<
    *
    * @private
    */
-  _remove(socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>): void {
+  _remove(
+    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
+  ): void {
     if (this.sockets.has(socket.id)) {
       const nsp = this.sockets.get(socket.id)!.nsp.name;
       this.sockets.delete(socket.id);
@@ -240,6 +248,7 @@ export class Client<
     try {
       this.decoder.add(data);
     } catch (e) {
+      debug("invalid packet format");
       this.onerror(e);
     }
   }
@@ -250,22 +259,31 @@ export class Client<
    * @private
    */
   private ondecoded(packet: Packet): void {
-    if (PacketType.CONNECT === packet.type) {
-      if (this.conn.protocol === 3) {
-        const parsed = url.parse(packet.nsp, true);
-        this.connect(parsed.pathname!, parsed.query);
-      } else {
-        this.connect(packet.nsp, packet.data);
-      }
+    let namespace: string;
+    let authPayload;
+    if (this.conn.protocol === 3) {
+      const parsed = url.parse(packet.nsp, true);
+      namespace = parsed.pathname!;
+      authPayload = parsed.query;
     } else {
-      const socket = this.nsps.get(packet.nsp);
-      if (socket) {
-        process.nextTick(function () {
-          socket._onpacket(packet);
-        });
-      } else {
-        debug("no socket for namespace %s", packet.nsp);
-      }
+      namespace = packet.nsp;
+      authPayload = packet.data;
+    }
+    const socket = this.nsps.get(namespace);
+
+    if (!socket && packet.type === PacketType.CONNECT) {
+      this.connect(namespace, authPayload);
+    } else if (
+      socket &&
+      packet.type !== PacketType.CONNECT &&
+      packet.type !== PacketType.CONNECT_ERROR
+    ) {
+      process.nextTick(function () {
+        socket._onpacket(packet);
+      });
+    } else {
+      debug("invalid state (packet type: %s)", packet.type);
+      this.close();
     }
   }
 

lib/index.ts

@@ -1,4 +1,5 @@
 import http = require("http");
+import type { Server as HTTPSServer } from "https";
 import { createReadStream } from "fs";
 import { createDeflate, createGzip, createBrotliCompress } from "zlib";
 import accepts = require("accepts");
@@ -9,6 +10,7 @@ import {
   Server as Engine,
   ServerOptions as EngineOptions,
   AttachOptions,
+  uServer,
 } from "engine.io";
 import { Client } from "./client";
 import { EventEmitter } from "events";
@@ -27,6 +29,7 @@ import {
   StrictEventEmitter,
   EventNames,
 } from "./typed-events";
+import { patchAdapter, restoreAdapter, serveFile } from "./uws";
 
 const debug = debugModule("socket.io:server");
 
@@ -72,16 +75,23 @@ interface ServerOptions extends EngineOptions, AttachOptions {
 export class Server<
   ListenEvents extends EventsMap = DefaultEventsMap,
   EmitEvents extends EventsMap = ListenEvents,
-  ServerSideEvents extends EventsMap = DefaultEventsMap
+  ServerSideEvents extends EventsMap = DefaultEventsMap,
+  SocketData = any
 > extends StrictEventEmitter<
   ServerSideEvents,
   EmitEvents,
-  ServerReservedEventsMap<ListenEvents, EmitEvents, ServerSideEvents>
+  ServerReservedEventsMap<
+    ListenEvents,
+    EmitEvents,
+    ServerSideEvents,
+    SocketData
+  >
 > {
   public readonly sockets: Namespace<
     ListenEvents,
     EmitEvents,
-    ServerSideEvents
+    ServerSideEvents,
+    SocketData
   >;
   /**
    * A reference to the underlying Engine.IO server.
@@ -103,11 +113,13 @@ export class Server<
   /**
    * @private
    */
-  _nsps: Map<string, Namespace<ListenEvents, EmitEvents, ServerSideEvents>> =
-    new Map();
+  _nsps: Map<
+    string,
+    Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
+  > = new Map();
   private parentNsps: Map<
     ParentNspNameMatchFn,
-    ParentNamespace<ListenEvents, EmitEvents, ServerSideEvents>
+    ParentNamespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
   > = new Map();
   private _adapter?: AdapterConstructor;
   private _serveClient: boolean;
@@ -120,7 +132,7 @@ export class Server<
    * @private
    */
   _connectTimeout: number;
-  private httpServer: http.Server;
+  private httpServer: http.Server | HTTPSServer;
 
   /**
    * Server constructor.
@@ -130,13 +142,26 @@ export class Server<
    * @public
    */
   constructor(opts?: Partial<ServerOptions>);
-  constructor(srv?: http.Server | number, opts?: Partial<ServerOptions>);
   constructor(
-    srv: undefined | Partial<ServerOptions> | http.Server | number,
+    srv?: http.Server | HTTPSServer | number,
     opts?: Partial<ServerOptions>
   );
   constructor(
-    srv: undefined | Partial<ServerOptions> | http.Server | number,
+    srv:
+      | undefined
+      | Partial<ServerOptions>
+      | http.Server
+      | HTTPSServer
+      | number,
+    opts?: Partial<ServerOptions>
+  );
+  constructor(
+    srv:
+      | undefined
+      | Partial<ServerOptions>
+      | http.Server
+      | HTTPSServer
+      | number,
     opts: Partial<ServerOptions> = {}
   ) {
     super();
@@ -156,7 +181,8 @@ export class Server<
     this.adapter(opts.adapter || Adapter);
     this.sockets = this.of("/");
     this.opts = opts;
-    if (srv || typeof srv == "number") this.attach(srv as http.Server | number);
+    if (srv || typeof srv == "number")
+      this.attach(srv as http.Server | HTTPSServer | number);
   }
 
   /**
@@ -188,7 +214,9 @@ export class Server<
     name: string,
     auth: { [key: string]: any },
     fn: (
-      nsp: Namespace<ListenEvents, EmitEvents, ServerSideEvents> | false
+      nsp:
+        | Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
+        | false
     ) => void
   ): void {
     if (this.parentNsps.size === 0) return fn(false);
@@ -287,7 +315,7 @@ export class Server<
    * @public
    */
   public listen(
-    srv: http.Server | number,
+    srv: http.Server | HTTPSServer | number,
     opts: Partial<ServerOptions> = {}
   ): this {
     return this.attach(srv, opts);
@@ -302,7 +330,7 @@ export class Server<
    * @public
    */
   public attach(
-    srv: http.Server | number,
+    srv: http.Server | HTTPSServer | number,
     opts: Partial<ServerOptions> = {}
   ): this {
     if ("function" == typeof srv) {
@@ -337,6 +365,69 @@ export class Server<
     return this;
   }
 
+  public attachApp(app /*: TemplatedApp */, opts: Partial<ServerOptions> = {}) {
+    // merge the options passed to the Socket.IO server
+    Object.assign(opts, this.opts);
+    // set engine.io path to `/socket.io`
+    opts.path = opts.path || this._path;
+
+    // initialize engine
+    debug("creating uWebSockets.js-based engine with opts %j", opts);
+    const engine = new uServer(opts);
+
+    engine.attach(app, opts);
+
+    // bind to engine events
+    this.bind(engine);
+
+    if (this._serveClient) {
+      // attach static file serving
+      app.get(`${this._path}/*`, (res, req) => {
+        if (!this.clientPathRegex.test(req.getUrl())) {
+          req.setYield(true);
+          return;
+        }
+
+        const filename = req
+          .getUrl()
+          .replace(this._path, "")
+          .replace(/\?.*$/, "")
+          .replace(/^\//, "");
+        const isMap = dotMapRegex.test(filename);
+        const type = isMap ? "map" : "source";
+
+        // Per the standard, ETags must be quoted:
+        // https://tools.ietf.org/html/rfc7232#section-2.3
+        const expectedEtag = '"' + clientVersion + '"';
+        const weakEtag = "W/" + expectedEtag;
+
+        const etag = req.getHeader("if-none-match");
+        if (etag) {
+          if (expectedEtag === etag || weakEtag === etag) {
+            debug("serve client %s 304", type);
+            res.writeStatus("304 Not Modified");
+            res.end();
+            return;
+          }
+        }
+
+        debug("serve client %s", type);
+
+        res.writeHeader("cache-control", "public, max-age=0");
+        res.writeHeader(
+          "content-type",
+          "application/" + (isMap ? "json" : "javascript")
+        );
+        res.writeHeader("etag", expectedEtag);
+
+        const filepath = path.join(__dirname, "../client-dist/", filename);
+        serveFile(res, filepath);
+      });
+    }
+
+    patchAdapter(app);
+  }
+
   /**
    * Initialize engine
    *
@@ -345,7 +436,7 @@ export class Server<
    * @private
    */
   private initEngine(
-    srv: http.Server,
+    srv: http.Server | HTTPSServer,
     opts: EngineOptions & AttachOptions
   ): void {
     // initialize engine
@@ -368,7 +459,7 @@ export class Server<
    * @param srv http server
    * @private
    */
-  private attachServe(srv: http.Server): void {
+  private attachServe(srv: http.Server | HTTPSServer): void {
     debug("attaching client serving req handler");
 
     const evs = srv.listeners("request").slice(0);
@@ -504,8 +595,10 @@ export class Server<
    */
   public of(
     name: string | RegExp | ParentNspNameMatchFn,
-    fn?: (socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>) => void
-  ): Namespace<ListenEvents, EmitEvents, ServerSideEvents> {
+    fn?: (
+      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
+    ) => void
+  ): Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData> {
     if (typeof name === "function" || name instanceof RegExp) {
       const parentNsp = new ParentNamespace(this);
       debug("initializing parent namespace %s", parentNsp.name);
@@ -553,6 +646,9 @@ export class Server<
 
     this.engine.close();
 
+    // restore the Adapter prototype
+    restoreAdapter();
+
     if (this.httpServer) {
       this.httpServer.close(fn);
     } else {
@@ -568,7 +664,7 @@ export class Server<
    */
   public use(
     fn: (
-      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>,
+      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>,
       next: (err?: ExtendedError) => void
     ) => void
   ): this {
@@ -583,7 +679,7 @@ export class Server<
    * @return self
    * @public
    */
-  public to(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public to(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
     return this.sockets.to(room);
   }
 
@@ -594,7 +690,7 @@ export class Server<
    * @return self
    * @public
    */
-  public in(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public in(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
     return this.sockets.in(room);
   }
 
@@ -605,7 +701,9 @@ export class Server<
    * @return self
    * @public
    */
-  public except(name: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public except(
+    name: Room | Room[]
+  ): BroadcastOperator<EmitEvents, SocketData> {
     return this.sockets.except(name);
   }
 
@@ -661,7 +759,9 @@ export class Server<
    * @return self
    * @public
    */
-  public compress(compress: boolean): BroadcastOperator<EmitEvents> {
+  public compress(
+    compress: boolean
+  ): BroadcastOperator<EmitEvents, SocketData> {
     return this.sockets.compress(compress);
   }
 
@@ -673,7 +773,7 @@ export class Server<
    * @return self
    * @public
    */
-  public get volatile(): BroadcastOperator<EmitEvents> {
+  public get volatile(): BroadcastOperator<EmitEvents, SocketData> {
     return this.sockets.volatile;
   }
 
@@ -683,16 +783,33 @@ export class Server<
    * @return self
    * @public
    */
-  public get local(): BroadcastOperator<EmitEvents> {
+  public get local(): BroadcastOperator<EmitEvents, SocketData> {
     return this.sockets.local;
   }
 
+  /**
+   * Adds a timeout in milliseconds for the next operation
+   *
+   * <pre><code>
+   *
+   * io.timeout(1000).emit("some-event", (err, responses) => {
+   *   // ...
+   * });
+   *
+   * </pre></code>
+   *
+   * @param timeout
+   */
+  public timeout(timeout: number) {
+    return this.sockets.timeout(timeout);
+  }
+
   /**
    * Returns the matching socket instances
    *
    * @public
    */
-  public fetchSockets(): Promise<RemoteSocket<EmitEvents>[]> {
+  public fetchSockets(): Promise<RemoteSocket<EmitEvents, SocketData>[]> {
     return this.sockets.fetchSockets();
   }
 
@@ -749,3 +866,4 @@ module.exports.Namespace = Namespace;
 module.exports.Socket = Socket;
 
 export { Socket, ServerOptions, Namespace, BroadcastOperator, RemoteSocket };
+export { Event } from "./socket";

lib/namespace.ts

@@ -21,56 +21,72 @@ export interface ExtendedError extends Error {
 export interface NamespaceReservedEventsMap<
   ListenEvents extends EventsMap,
   EmitEvents extends EventsMap,
-  ServerSideEvents extends EventsMap
+  ServerSideEvents extends EventsMap,
+  SocketData
 > {
-  connect: (socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>) => void;
+  connect: (
+    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
+  ) => void;
   connection: (
-    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>
+    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
   ) => void;
 }
 
 export interface ServerReservedEventsMap<
   ListenEvents,
   EmitEvents,
-  ServerSideEvents
+  ServerSideEvents,
+  SocketData
 > extends NamespaceReservedEventsMap<
     ListenEvents,
     EmitEvents,
-    ServerSideEvents
+    ServerSideEvents,
+    SocketData
   > {
   new_namespace: (
-    namespace: Namespace<ListenEvents, EmitEvents, ServerSideEvents>
+    namespace: Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
   ) => void;
 }
 
 export const RESERVED_EVENTS: ReadonlySet<string | Symbol> = new Set<
-  keyof ServerReservedEventsMap<never, never, never>
+  keyof ServerReservedEventsMap<never, never, never, never>
 >(<const>["connect", "connection", "new_namespace"]);
 
 export class Namespace<
   ListenEvents extends EventsMap = DefaultEventsMap,
   EmitEvents extends EventsMap = ListenEvents,
-  ServerSideEvents extends EventsMap = DefaultEventsMap
+  ServerSideEvents extends EventsMap = DefaultEventsMap,
+  SocketData = any
 > extends StrictEventEmitter<
   ServerSideEvents,
   EmitEvents,
-  NamespaceReservedEventsMap<ListenEvents, EmitEvents, ServerSideEvents>
+  NamespaceReservedEventsMap<
+    ListenEvents,
+    EmitEvents,
+    ServerSideEvents,
+    SocketData
+  >
 > {
   public readonly name: string;
   public readonly sockets: Map<
     SocketId,
-    Socket<ListenEvents, EmitEvents, ServerSideEvents>
+    Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
   > = new Map();
 
   public adapter: Adapter;
 
   /** @private */
-  readonly server: Server<ListenEvents, EmitEvents, ServerSideEvents>;
+  readonly server: Server<
+    ListenEvents,
+    EmitEvents,
+    ServerSideEvents,
+    SocketData
+  >;
 
   /** @private */
   _fns: Array<
     (
-      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>,
+      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>,
       next: (err?: ExtendedError) => void
     ) => void
   > = [];
@@ -85,7 +101,7 @@ export class Namespace<
    * @param name
    */
   constructor(
-    server: Server<ListenEvents, EmitEvents, ServerSideEvents>,
+    server: Server<ListenEvents, EmitEvents, ServerSideEvents, SocketData>,
     name: string
   ) {
     super();
@@ -114,7 +130,7 @@ export class Namespace<
    */
   public use(
     fn: (
-      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>,
+      socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>,
       next: (err?: ExtendedError) => void
     ) => void
   ): this {
@@ -130,7 +146,7 @@ export class Namespace<
    * @private
    */
   private run(
-    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>,
+    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>,
     fn: (err: ExtendedError | null) => void
   ) {
     const fns = this._fns.slice(0);
@@ -159,7 +175,7 @@ export class Namespace<
    * @return self
    * @public
    */
-  public to(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public to(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
     return new BroadcastOperator(this.adapter).to(room);
   }
 
@@ -170,7 +186,7 @@ export class Namespace<
    * @return self
    * @public
    */
-  public in(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public in(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
     return new BroadcastOperator(this.adapter).in(room);
   }
 
@@ -181,7 +197,9 @@ export class Namespace<
    * @return self
    * @public
    */
-  public except(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public except(
+    room: Room | Room[]
+  ): BroadcastOperator<EmitEvents, SocketData> {
     return new BroadcastOperator(this.adapter).except(room);
   }
 
@@ -195,7 +213,7 @@ export class Namespace<
     client: Client<ListenEvents, EmitEvents, ServerSideEvents>,
     query,
     fn?: () => void
-  ): Socket<ListenEvents, EmitEvents, ServerSideEvents> {
+  ): Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData> {
     debug("adding socket to nsp %s", this.name);
     const socket = new Socket(this, client, query);
     this.run(socket, (err) => {
@@ -238,7 +256,9 @@ export class Namespace<
    *
    * @private
    */
-  _remove(socket: Socket<ListenEvents, EmitEvents, ServerSideEvents>): void {
+  _remove(
+    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
+  ): void {
     if (this.sockets.has(socket.id)) {
       this.sockets.delete(socket.id);
     } else {
@@ -256,7 +276,10 @@ export class Namespace<
     ev: Ev,
     ...args: EventParams<EmitEvents, Ev>
   ): boolean {
-    return new BroadcastOperator<EmitEvents>(this.adapter).emit(ev, ...args);
+    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).emit(
+      ev,
+      ...args
+    );
   }
 
   /**
@@ -328,7 +351,9 @@ export class Namespace<
    * @return self
    * @public
    */
-  public compress(compress: boolean): BroadcastOperator<EmitEvents> {
+  public compress(
+    compress: boolean
+  ): BroadcastOperator<EmitEvents, SocketData> {
     return new BroadcastOperator(this.adapter).compress(compress);
   }
 
@@ -340,7 +365,7 @@ export class Namespace<
    * @return self
    * @public
    */
-  public get volatile(): BroadcastOperator<EmitEvents> {
+  public get volatile(): BroadcastOperator<EmitEvents, SocketData> {
     return new BroadcastOperator(this.adapter).volatile;
   }
 
@@ -350,16 +375,33 @@ export class Namespace<
    * @return self
    * @public
    */
-  public get local(): BroadcastOperator<EmitEvents> {
+  public get local(): BroadcastOperator<EmitEvents, SocketData> {
     return new BroadcastOperator(this.adapter).local;
   }
 
+  /**
+   * Adds a timeout in milliseconds for the next operation
+   *
+   * <pre><code>
+   *
+   * io.timeout(1000).emit("some-event", (err, responses) => {
+   *   // ...
+   * });
+   *
+   * </pre></code>
+   *
+   * @param timeout
+   */
+  public timeout(timeout: number) {
+    return new BroadcastOperator(this.adapter).timeout(timeout);
+  }
+
   /**
    * Returns the matching socket instances
    *
    * @public
    */
-  public fetchSockets(): Promise<RemoteSocket<EmitEvents>[]> {
+  public fetchSockets(): Promise<RemoteSocket<EmitEvents, SocketData>[]> {
     return new BroadcastOperator(this.adapter).fetchSockets();
   }
 

lib/parent-namespace.ts

@@ -1,5 +1,5 @@
 import { Namespace } from "./namespace";
-import type { Server } from "./index";
+import type { Server, RemoteSocket } from "./index";
 import type {
   EventParams,
   EventNames,
@@ -11,13 +11,17 @@ import type { BroadcastOptions } from "socket.io-adapter";
 export class ParentNamespace<
   ListenEvents extends EventsMap = DefaultEventsMap,
   EmitEvents extends EventsMap = ListenEvents,
-  ServerSideEvents extends EventsMap = DefaultEventsMap
-> extends Namespace<ListenEvents, EmitEvents, ServerSideEvents> {
+  ServerSideEvents extends EventsMap = DefaultEventsMap,
+  SocketData = any
+> extends Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData> {
   private static count: number = 0;
-  private children: Set<Namespace<ListenEvents, EmitEvents, ServerSideEvents>> =
-    new Set();
+  private children: Set<
+    Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
+  > = new Set();
 
-  constructor(server: Server<ListenEvents, EmitEvents, ServerSideEvents>) {
+  constructor(
+    server: Server<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
+  ) {
     super(server, "/_" + ParentNamespace.count++);
   }
 
@@ -47,7 +51,7 @@ export class ParentNamespace<
 
   createChild(
     name: string
-  ): Namespace<ListenEvents, EmitEvents, ServerSideEvents> {
+  ): Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData> {
     const namespace = new Namespace(this.server, name);
     namespace._fns = this._fns.slice(0);
     this.listeners("connect").forEach((listener) =>
@@ -60,4 +64,13 @@ export class ParentNamespace<
     this.server._nsps.set(name, namespace);
     return namespace;
   }
+
+  fetchSockets(): Promise<RemoteSocket<EmitEvents, SocketData>[]> {
+    // note: we could make the fetchSockets() method work for dynamic namespaces created with a regex (by sending the
+    // regex to the other Socket.IO servers, and returning the sockets of each matching namespace for example), but
+    // the behavior for namespaces created with a function is less clear
+    // note²: we cannot loop over each children namespace, because with multiple Socket.IO servers, a given namespace
+    // may exist on one node but not exist on another (since it is created upon client connection)
+    throw new Error("fetchSockets() is not supported on parent namespaces");
+  }
 }

lib/socket.ts

@@ -1,5 +1,4 @@
 import { Packet, PacketType } from "socket.io-parser";
-import url = require("url");
 import debugModule from "debug";
 import type { Server } from "./index";
 import {
@@ -46,7 +45,7 @@ export interface EventEmitterReservedEventsMap {
 
 export const RESERVED_EVENTS: ReadonlySet<string | Symbol> = new Set<
   | ClientReservedEvents
-  | keyof NamespaceReservedEventsMap<never, never, never>
+  | keyof NamespaceReservedEventsMap<never, never, never, never>
   | keyof SocketReservedEventsMap
   | keyof EventEmitterReservedEventsMap
 >(<const>[
@@ -108,12 +107,16 @@ export interface Handshake {
   auth: { [key: string]: any };
 }
 
-type Event = [eventName: string, ...args: any[]];
+/**
+ * `[eventName, ...args]`
+ */
+export type Event = [string, ...any[]];
 
 export class Socket<
   ListenEvents extends EventsMap = DefaultEventsMap,
   EmitEvents extends EventsMap = ListenEvents,
-  ServerSideEvents extends EventsMap = DefaultEventsMap
+  ServerSideEvents extends EventsMap = DefaultEventsMap,
+  SocketData = any
 > extends StrictEventEmitter<
   ListenEvents,
   EmitEvents,
@@ -124,17 +127,22 @@ export class Socket<
   /**
    * Additional information that can be attached to the Socket instance and which will be used in the fetchSockets method
    */
-  public data: any = {};
+  public data: Partial<SocketData> = {};
 
-  public connected: boolean;
-  public disconnected: boolean;
+  public connected: boolean = false;
 
-  private readonly server: Server<ListenEvents, EmitEvents, ServerSideEvents>;
+  private readonly server: Server<
+    ListenEvents,
+    EmitEvents,
+    ServerSideEvents,
+    SocketData
+  >;
   private readonly adapter: Adapter;
   private acks: Map<number, () => void> = new Map();
   private fns: Array<(event: Event, next: (err?: Error) => void) => void> = [];
   private flags: BroadcastFlags = {};
   private _anyListeners?: Array<(...args: any[]) => void>;
+  private _anyOutgoingListeners?: Array<(...args: any[]) => void>;
 
   /**
    * Interface to a `Client` for a given `Namespace`.
@@ -158,8 +166,6 @@ export class Socket<
     } else {
       this.id = base64id.generateId(); // don't reuse the Engine.IO id because it's sensitive information
     }
-    this.connected = true;
-    this.disconnected = false;
     this.handshake = this.buildHandshake(auth);
   }
 
@@ -178,7 +184,8 @@ export class Socket<
       secure: !!this.request.connection.encrypted,
       issued: +new Date(),
       url: this.request.url!,
-      query: url.parse(this.request.url!, true).query,
+      // @ts-ignore
+      query: this.request._query,
       auth,
     };
   }
@@ -204,19 +211,44 @@ export class Socket<
 
     // access last argument to see if it's an ACK callback
     if (typeof data[data.length - 1] === "function") {
-      debug("emitting packet with ack id %d", this.nsp._ids);
-      this.acks.set(this.nsp._ids, data.pop());
-      packet.id = this.nsp._ids++;
+      const id = this.nsp._ids++;
+      debug("emitting packet with ack id %d", id);
+
+      this.registerAckCallback(id, data.pop());
+      packet.id = id;
     }
 
     const flags = Object.assign({}, this.flags);
     this.flags = {};
 
+    this.notifyOutgoingListeners(packet);
     this.packet(packet, flags);
 
     return true;
   }
 
+  /**
+   * @private
+   */
+  private registerAckCallback(id: number, ack: (...args: any[]) => void): void {
+    const timeout = this.flags.timeout;
+    if (timeout === undefined) {
+      this.acks.set(id, ack);
+      return;
+    }
+
+    const timer = setTimeout(() => {
+      debug("event with ack id %d has timed out after %d ms", id, timeout);
+      this.acks.delete(id);
+      ack.call(this, new Error("operation has timed out"));
+    }, timeout);
+
+    this.acks.set(id, (...args) => {
+      clearTimeout(timer);
+      ack.apply(this, [null, ...args]);
+    });
+  }
+
   /**
    * Targets a room when broadcasting.
    *
@@ -224,7 +256,7 @@ export class Socket<
    * @return self
    * @public
    */
-  public to(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public to(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
     return this.newBroadcastOperator().to(room);
   }
 
@@ -235,7 +267,7 @@ export class Socket<
    * @return self
    * @public
    */
-  public in(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public in(room: Room | Room[]): BroadcastOperator<EmitEvents, SocketData> {
     return this.newBroadcastOperator().in(room);
   }
 
@@ -246,7 +278,9 @@ export class Socket<
    * @return self
    * @public
    */
-  public except(room: Room | Room[]): BroadcastOperator<EmitEvents> {
+  public except(
+    room: Room | Room[]
+  ): BroadcastOperator<EmitEvents, SocketData> {
     return this.newBroadcastOperator().except(room);
   }
 
@@ -336,6 +370,7 @@ export class Socket<
    */
   _onconnect(): void {
     debug("socket connected - writing packet");
+    this.connected = true;
     this.join(this.id);
     if (this.conn.protocol === 3) {
       this.packet({ type: PacketType.CONNECT });
@@ -372,9 +407,6 @@ export class Socket<
       case PacketType.DISCONNECT:
         this.ondisconnect();
         break;
-
-      case PacketType.CONNECT_ERROR:
-        this._onerror(new Error(packet.data));
     }
   }
 
@@ -483,7 +515,6 @@ export class Socket<
     this.nsp._remove(this);
     this.client._remove(this);
     this.connected = false;
-    this.disconnected = true;
     this.emitReserved("disconnect", reason);
     return;
   }
@@ -550,7 +581,7 @@ export class Socket<
    * @return {Socket} self
    * @public
    */
-  public get broadcast(): BroadcastOperator<EmitEvents> {
+  public get broadcast(): BroadcastOperator<EmitEvents, SocketData> {
     return this.newBroadcastOperator();
   }
 
@@ -560,10 +591,30 @@ export class Socket<
    * @return {Socket} self
    * @public
    */
-  public get local(): BroadcastOperator<EmitEvents> {
+  public get local(): BroadcastOperator<EmitEvents, SocketData> {
     return this.newBroadcastOperator().local;
   }
 
+  /**
+   * Sets a modifier for a subsequent event emission that the callback will be called with an error when the
+   * given number of milliseconds have elapsed without an acknowledgement from the client:
+   *
+   * ```
+   * socket.timeout(5000).emit("my-event", (err) => {
+   *   if (err) {
+   *     // the client did not acknowledge the event in the given delay
+   *   }
+   * });
+   * ```
+   *
+   * @returns self
+   * @public
+   */
+  public timeout(timeout: number): this {
+    this.flags.timeout = timeout;
+    return this;
+  }
+
   /**
    * Dispatch incoming event to socket listeners.
    *
@@ -625,6 +676,13 @@ export class Socket<
     run(0);
   }
 
+  /**
+   * Whether the socket is currently disconnected
+   */
+  public get disconnected() {
+    return !this.connected;
+  }
+
   /**
    * A reference to the request that originated the underlying Engine.IO Socket.
    *
@@ -651,8 +709,8 @@ export class Socket<
   }
 
   /**
-   * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
-   * callback.
+   * Adds a listener that will be fired when any event is received. The event name is passed as the first argument to
+   * the callback.
    *
    * @param listener
    * @public
@@ -664,8 +722,8 @@ export class Socket<
   }
 
   /**
-   * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
-   * callback. The listener is added to the beginning of the listeners array.
+   * Adds a listener that will be fired when any event is received. The event name is passed as the first argument to
+   * the callback. The listener is added to the beginning of the listeners array.
    *
    * @param listener
    * @public
@@ -677,7 +735,7 @@ export class Socket<
   }
 
   /**
-   * Removes the listener that will be fired when any event is emitted.
+   * Removes the listener that will be fired when any event is received.
    *
    * @param listener
    * @public
@@ -710,7 +768,115 @@ export class Socket<
     return this._anyListeners || [];
   }
 
-  private newBroadcastOperator(): BroadcastOperator<EmitEvents> {
+  /**
+   * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
+   * callback.
+   *
+   * @param listener
+   *
+   * <pre><code>
+   *
+   * socket.onAnyOutgoing((event, ...args) => {
+   *   console.log(event);
+   * });
+   *
+   * </pre></code>
+   *
+   * @public
+   */
+  public onAnyOutgoing(listener: (...args: any[]) => void): this {
+    this._anyOutgoingListeners = this._anyOutgoingListeners || [];
+    this._anyOutgoingListeners.push(listener);
+    return this;
+  }
+
+  /**
+   * Adds a listener that will be fired when any event is emitted. The event name is passed as the first argument to the
+   * callback. The listener is added to the beginning of the listeners array.
+   *
+   * @param listener
+   *
+   * <pre><code>
+   *
+   * socket.prependAnyOutgoing((event, ...args) => {
+   *   console.log(event);
+   * });
+   *
+   * </pre></code>
+   *
+   * @public
+   */
+  public prependAnyOutgoing(listener: (...args: any[]) => void): this {
+    this._anyOutgoingListeners = this._anyOutgoingListeners || [];
+    this._anyOutgoingListeners.unshift(listener);
+    return this;
+  }
+
+  /**
+   * Removes the listener that will be fired when any event is emitted.
+   *
+   * @param listener
+   *
+   * <pre><code>
+   *
+   * const handler = (event, ...args) => {
+   *   console.log(event);
+   * }
+   *
+   * socket.onAnyOutgoing(handler);
+   *
+   * // then later
+   * socket.offAnyOutgoing(handler);
+   *
+   * </pre></code>
+   *
+   * @public
+   */
+  public offAnyOutgoing(listener?: (...args: any[]) => void): this {
+    if (!this._anyOutgoingListeners) {
+      return this;
+    }
+    if (listener) {
+      const listeners = this._anyOutgoingListeners;
+      for (let i = 0; i < listeners.length; i++) {
+        if (listener === listeners[i]) {
+          listeners.splice(i, 1);
+          return this;
+        }
+      }
+    } else {
+      this._anyOutgoingListeners = [];
+    }
+    return this;
+  }
+
+  /**
+   * Returns an array of listeners that are listening for any event that is specified. This array can be manipulated,
+   * e.g. to remove listeners.
+   *
+   * @public
+   */
+  public listenersAnyOutgoing() {
+    return this._anyOutgoingListeners || [];
+  }
+
+  /**
+   * Notify the listeners for each packet sent (emit or broadcast)
+   *
+   * @param packet
+   *
+   * @private
+   */
+  private notifyOutgoingListeners(packet: Packet) {
+    if (this._anyOutgoingListeners && this._anyOutgoingListeners.length) {
+      const listeners = this._anyOutgoingListeners.slice();
+      for (const listener of listeners) {
+        listener.apply(this, packet.data);
+      }
+    }
+  }
+
+  private newBroadcastOperator(): BroadcastOperator<EmitEvents, SocketData> {
     const flags = Object.assign({}, this.flags);
     this.flags = {};
     return new BroadcastOperator(

lib/uws.ts

@@ -0,0 +1,162 @@
+import { Adapter, Room } from "socket.io-adapter";
+import type { WebSocket } from "uWebSockets.js";
+import type { Socket } from "./socket.js";
+import { createReadStream, statSync } from "fs";
+import debugModule from "debug";
+
+const debug = debugModule("socket.io:adapter-uws");
+
+const SEPARATOR = "\x1f"; // see https://en.wikipedia.org/wiki/Delimiter#ASCII_delimited_text
+
+const { addAll, del, broadcast } = Adapter.prototype;
+
+export function patchAdapter(app /* : TemplatedApp */) {
+  Adapter.prototype.addAll = function (id, rooms) {
+    const isNew = !this.sids.has(id);
+    addAll.call(this, id, rooms);
+    const socket: Socket = this.nsp.sockets.get(id);
+    if (!socket) {
+      return;
+    }
+    if (socket.conn.transport.name === "websocket") {
+      subscribe(this.nsp.name, socket, isNew, rooms);
+      return;
+    }
+    if (isNew) {
+      socket.conn.on("upgrade", () => {
+        const rooms = this.sids.get(id);
+        subscribe(this.nsp.name, socket, isNew, rooms);
+      });
+    }
+  };
+
+  Adapter.prototype.del = function (id, room) {
+    del.call(this, id, room);
+    const socket: Socket = this.nsp.sockets.get(id);
+    if (socket && socket.conn.transport.name === "websocket") {
+      // @ts-ignore
+      const sessionId = socket.conn.id;
+      // @ts-ignore
+      const websocket: WebSocket = socket.conn.transport.socket;
+      const topic = `${this.nsp.name}${SEPARATOR}${room}`;
+      debug("unsubscribe connection %s from topic %s", sessionId, topic);
+      websocket.unsubscribe(topic);
+    }
+  };
+
+  Adapter.prototype.broadcast = function (packet, opts) {
+    const useFastPublish = opts.rooms.size <= 1 && opts.except!.size === 0;
+    if (!useFastPublish) {
+      broadcast.call(this, packet, opts);
+      return;
+    }
+
+    const flags = opts.flags || {};
+    const basePacketOpts = {
+      preEncoded: true,
+      volatile: flags.volatile,
+      compress: flags.compress,
+    };
+
+    packet.nsp = this.nsp.name;
+    const encodedPackets = this.encoder.encode(packet);
+
+    const topic =
+      opts.rooms.size === 0
+        ? this.nsp.name
+        : `${this.nsp.name}${SEPARATOR}${opts.rooms.keys().next().value}`;
+    debug("fast publish to %s", topic);
+
+    // fast publish for clients connected with WebSocket
+    encodedPackets.forEach((encodedPacket) => {
+      const isBinary = typeof encodedPacket !== "string";
+      // "4" being the message type in the Engine.IO protocol, see https://github.com/socketio/engine.io-protocol
+      app.publish(
+        topic,
+        isBinary ? encodedPacket : "4" + encodedPacket,
+        isBinary
+      );
+    });
+
+    this.apply(opts, (socket) => {
+      if (socket.conn.transport.name !== "websocket") {
+        // classic publish for clients connected with HTTP long-polling
+        socket.client.writeToEngine(encodedPackets, basePacketOpts);
+      }
+    });
+  };
+}
+
+function subscribe(
+  namespaceName: string,
+  socket: Socket,
+  isNew: boolean,
+  rooms: Set<Room>
+) {
+  // @ts-ignore
+  const sessionId = socket.conn.id;
+  // @ts-ignore
+  const websocket: WebSocket = socket.conn.transport.socket;
+  if (isNew) {
+    debug("subscribe connection %s to topic %s", sessionId, namespaceName);
+    websocket.subscribe(namespaceName);
+  }
+  rooms.forEach((room) => {
+    const topic = `${namespaceName}${SEPARATOR}${room}`; // '#' can be used as wildcard
+    debug("subscribe connection %s to topic %s", sessionId, topic);
+    websocket.subscribe(topic);
+  });
+}
+
+export function restoreAdapter() {
+  Adapter.prototype.addAll = addAll;
+  Adapter.prototype.del = del;
+  Adapter.prototype.broadcast = broadcast;
+}
+
+const toArrayBuffer = (buffer: Buffer) => {
+  const { buffer: arrayBuffer, byteOffset, byteLength } = buffer;
+  return arrayBuffer.slice(byteOffset, byteOffset + byteLength);
+};
+
+// imported from https://github.com/kolodziejczak-sz/uwebsocket-serve
+export function serveFile(res /* : HttpResponse */, filepath: string) {
+  const { size } = statSync(filepath);
+  const readStream = createReadStream(filepath);
+  const destroyReadStream = () => !readStream.destroyed && readStream.destroy();
+
+  const onError = (error: Error) => {
+    destroyReadStream();
+    throw error;
+  };
+
+  const onDataChunk = (chunk: Buffer) => {
+    const arrayBufferChunk = toArrayBuffer(chunk);
+
+    const lastOffset = res.getWriteOffset();
+    const [ok, done] = res.tryEnd(arrayBufferChunk, size);
+
+    if (!done && !ok) {
+      readStream.pause();
+
+      res.onWritable((offset) => {
+        const [ok, done] = res.tryEnd(
+          arrayBufferChunk.slice(offset - lastOffset),
+          size
+        );
+
+        if (!done && ok) {
+          readStream.resume();
+        }
+
+        return ok;
+      });
+    }
+  };
+
+  res.onAborted(destroyReadStream);
+  readStream
+    .on("data", onDataChunk)
+    .on("error", onError)
+    .on("end", destroyReadStream);
+}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "socket.io",
-  "version": "4.3.2",
+  "version": "4.5.1",
   "description": "node.js realtime framework server",
   "keywords": [
     "realtime",
@@ -27,7 +27,8 @@
   "main": "./dist/index.js",
   "exports": {
     "import": "./wrapper.mjs",
-    "require": "./dist/index.js"
+    "require": "./dist/index.js",
+    "types": "./dist/index.d.ts"
   },
   "types": "./dist/index.d.ts",
   "license": "MIT",
@@ -48,8 +49,8 @@
     "accepts": "~1.3.4",
     "base64id": "~2.0.0",
     "debug": "~4.3.2",
-    "engine.io": "~6.0.0",
-    "socket.io-adapter": "~2.3.2",
+    "engine.io": "~6.2.0",
+    "socket.io-adapter": "~2.4.0",
     "socket.io-parser": "~4.0.4"
   },
   "devDependencies": {
@@ -59,13 +60,14 @@
     "nyc": "^15.1.0",
     "prettier": "^2.3.2",
     "rimraf": "^3.0.2",
-    "socket.io-client": "4.3.2",
+    "socket.io-client": "4.5.1",
     "socket.io-client-v2": "npm:socket.io-client@^2.4.0",
     "superagent": "^6.1.0",
     "supertest": "^6.1.6",
     "ts-node": "^10.2.1",
     "tsd": "^0.17.0",
-    "typescript": "^4.4.2"
+    "typescript": "^4.4.2",
+    "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.0.0"
   },
   "contributors": [
     {

test/socket-timeout.ts

@@ -0,0 +1,57 @@
+import { Server } from "..";
+import { createClient, success } from "./support/util";
+import expect from "expect.js";
+
+describe("timeout", () => {
+  it("should timeout if the client does not acknowledge the event", (done) => {
+    const io = new Server(0);
+    const client = createClient(io, "/");
+
+    io.on("connection", (socket) => {
+      socket.timeout(50).emit("unknown", (err) => {
+        expect(err).to.be.an(Error);
+        success(done, io, client);
+      });
+    });
+  });
+
+  it("should timeout if the client does not acknowledge the event in time", (done) => {
+    const io = new Server(0);
+    const client = createClient(io, "/");
+
+    client.on("echo", (arg, cb) => {
+      cb(arg);
+    });
+
+    let count = 0;
+
+    io.on("connection", (socket) => {
+      socket.timeout(0).emit("echo", 42, (err) => {
+        expect(err).to.be.an(Error);
+        count++;
+      });
+    });
+
+    setTimeout(() => {
+      expect(count).to.eql(1);
+      success(done, io, client);
+    }, 200);
+  });
+
+  it("should not timeout if the client does acknowledge the event", (done) => {
+    const io = new Server(0);
+    const client = createClient(io, "/");
+
+    client.on("echo", (arg, cb) => {
+      cb(arg);
+    });
+
+    io.on("connection", (socket) => {
+      socket.timeout(50).emit("echo", 42, (err, value) => {
+        expect(err).to.be(null);
+        expect(value).to.be(42);
+        success(done, io, client);
+      });
+    });
+  });
+});

test/socket.io.ts

@@ -1,6 +1,6 @@
 "use strict";
 
-import { Server, Socket, Namespace } from "..";
+import { Server, Socket, Namespace } from "../lib";
 import { createServer } from "http";
 import fs = require("fs");
 import { join } from "path";
@@ -14,6 +14,7 @@ import { io as ioc, Socket as ClientSocket } from "socket.io-client";
 
 import "./support/util";
 import "./utility-methods";
+import "./uws";
 
 type callback = (err: Error | null, success: boolean) => void;
 
@@ -46,6 +47,44 @@ const getPort = (io: Server): number => {
   return io.httpServer.address().port;
 };
 
+// TODO: update superagent as latest release now supports promises
+const eioHandshake = (httpServer): Promise<string> => {
+  return new Promise((resolve) => {
+    request(httpServer)
+      .get("/socket.io/")
+      .query({ transport: "polling", EIO: 4 })
+      .end((err, res) => {
+        const sid = JSON.parse(res.text.substring(1)).sid;
+        resolve(sid);
+      });
+  });
+};
+
+const eioPush = (httpServer, sid: string, body: string): Promise<void> => {
+  return new Promise((resolve) => {
+    request(httpServer)
+      .post("/socket.io/")
+      .send(body)
+      .query({ transport: "polling", EIO: 4, sid })
+      .expect(200)
+      .end(() => {
+        resolve();
+      });
+  });
+};
+
+const eioPoll = (httpServer, sid): Promise<string> => {
+  return new Promise((resolve) => {
+    request(httpServer)
+      .get("/socket.io/")
+      .query({ transport: "polling", EIO: 4, sid })
+      .expect(200)
+      .end((err, res) => {
+        resolve(res.text);
+      });
+  });
+};
+
 describe("socket.io", () => {
   it("should be the same version as client", () => {
     const version = require("../package").version;
@@ -377,6 +416,66 @@ describe("socket.io", () => {
         exec(fixture("server-close.ts"), done);
       });
     });
+
+    describe("protocol violations", () => {
+      it("should close the connection when receiving several CONNECT packets", async () => {
+        const httpServer = createServer();
+        const io = new Server(httpServer);
+
+        httpServer.listen(0);
+
+        const sid = await eioHandshake(httpServer);
+        // send a first CONNECT packet
+        await eioPush(httpServer, sid, "40");
+        // send another CONNECT packet
+        await eioPush(httpServer, sid, "40");
+        // session is cleanly closed (not discarded, see 'client.close()')
+        // first, we receive the Socket.IO handshake response
+        await eioPoll(httpServer, sid);
+        // then a close packet
+        const body = await eioPoll(httpServer, sid);
+        expect(body).to.be("6\u001e1");
+
+        io.close();
+      });
+
+      it("should close the connection when receiving an EVENT packet while not connected", async () => {
+        const httpServer = createServer();
+        const io = new Server(httpServer);
+
+        httpServer.listen(0);
+
+        const sid = await eioHandshake(httpServer);
+        // send an EVENT packet
+        await eioPush(httpServer, sid, '42["some event"]');
+        // session is cleanly closed, we receive a close packet
+        const body = await eioPoll(httpServer, sid);
+        expect(body).to.be("6\u001e1");
+
+        io.close();
+      });
+
+      it("should close the connection when receiving an invalid packet", async () => {
+        const httpServer = createServer();
+        const io = new Server(httpServer);
+
+        httpServer.listen(0);
+
+        const sid = await eioHandshake(httpServer);
+        // send a CONNECT packet
+        await eioPush(httpServer, sid, "40");
+        // send an invalid packet
+        await eioPush(httpServer, sid, "4abc");
+        // session is cleanly closed (not discarded, see 'client.close()')
+        // first, we receive the Socket.IO handshake response
+        await eioPoll(httpServer, sid);
+        // then a close packet
+        const body = await eioPoll(httpServer, sid);
+        expect(body).to.be("6\u001e1");
+
+        io.close();
+      });
+    });
   });
 
   describe("namespaces", () => {
@@ -820,29 +919,6 @@ describe("socket.io", () => {
       });
     });
 
-    it("should close a client without namespace (2)", (done) => {
-      const srv = createServer();
-      const sio = new Server(srv, {
-        connectTimeout: 100,
-      });
-
-      sio.use((_, next) => {
-        next(new Error("nope"));
-      });
-
-      srv.listen(() => {
-        const socket = client(srv);
-
-        const success = () => {
-          socket.close();
-          sio.close();
-          done();
-        };
-
-        socket.on("disconnect", success);
-      });
-    });
-
     it("should exclude a specific socket when emitting", (done) => {
       const srv = createServer();
       const io = new Server(srv);
@@ -1072,7 +1148,7 @@ describe("socket.io", () => {
           reconnectionDelay: 100,
         });
         clientSocket.on("connect", () => {
-          srv.close();
+          sio.close();
         });
 
         clientSocket.io.on("reconnect_failed", () => {
@@ -1452,6 +1528,32 @@ describe("socket.io", () => {
       }, 200);
     });
 
+    it("should broadcast only one consecutive volatile event with binary (ws)", (done) => {
+      const srv = createServer();
+      const sio = new Server(srv, { transports: ["websocket"] });
+
+      let counter = 0;
+      srv.listen(() => {
+        sio.on("connection", (s) => {
+          // Wait to make sure there are no packets being sent for opening the connection
+          setTimeout(() => {
+            sio.volatile.emit("ev", Buffer.from([1, 2, 3]));
+            sio.volatile.emit("ev", Buffer.from([4, 5, 6]));
+          }, 20);
+        });
+
+        const socket = client(srv, { transports: ["websocket"] });
+        socket.on("ev", () => {
+          counter++;
+        });
+      });
+
+      setTimeout(() => {
+        expect(counter).to.be(1);
+        done();
+      }, 200);
+    });
+
     it("should emit regular events after trying a failed volatile event (polling)", (done) => {
       const srv = createServer();
       const sio = new Server(srv, { transports: ["polling"] });
@@ -1826,7 +1928,7 @@ describe("socket.io", () => {
           reconnectionDelay: 100,
         });
         clientSocket.once("connect", () => {
-          srv.close(() => {
+          sio.close(() => {
             clientSocket.io.on("reconnect", () => {
               clientSocket.emit("ev", "payload");
             });
@@ -2078,6 +2180,100 @@ describe("socket.io", () => {
         });
       });
     });
+
+    describe("onAnyOutgoing", () => {
+      it("should call listener", (done) => {
+        const srv = createServer();
+        const sio = new Server(srv);
+
+        srv.listen(() => {
+          const clientSocket = client(srv, { multiplex: false });
+
+          sio.on("connection", (socket) => {
+            socket.onAnyOutgoing((event, arg1) => {
+              expect(event).to.be("my-event");
+              expect(arg1).to.be("123");
+
+              success(sio, clientSocket, done);
+            });
+
+            socket.emit("my-event", "123");
+          });
+        });
+      });
+
+      it("should call listener when broadcasting", (done) => {
+        const srv = createServer();
+        const sio = new Server(srv);
+
+        srv.listen(() => {
+          const clientSocket = client(srv, { multiplex: false });
+
+          sio.on("connection", (socket) => {
+            socket.onAnyOutgoing((event, arg1) => {
+              expect(event).to.be("my-event");
+              expect(arg1).to.be("123");
+
+              success(sio, clientSocket, done);
+            });
+
+            sio.emit("my-event", "123");
+          });
+        });
+      });
+
+      it("should prepend listener", (done) => {
+        const srv = createServer();
+        const sio = new Server(srv);
+
+        srv.listen(async () => {
+          const clientSocket = client(srv, { multiplex: false });
+
+          const socket = (await waitFor(sio, "connection")) as Socket;
+
+          let count = 0;
+
+          socket.onAnyOutgoing((event, arg1) => {
+            expect(count).to.be(2);
+
+            success(sio, clientSocket, done);
+          });
+
+          socket.prependAnyOutgoing(() => {
+            expect(count++).to.be(1);
+          });
+
+          socket.prependAnyOutgoing(() => {
+            expect(count++).to.be(0);
+          });
+
+          socket.emit("my-event", "123");
+        });
+      });
+
+      it("should remove listener", (done) => {
+        const srv = createServer();
+        const sio = new Server(srv);
+
+        srv.listen(() => {
+          const clientSocket = client(srv, { multiplex: false });
+
+          sio.on("connection", (socket) => {
+            const fail = () => done(new Error("fail"));
+
+            socket.onAnyOutgoing(fail);
+            socket.offAnyOutgoing(fail);
+            expect(socket.listenersAnyOutgoing.length).to.be(0);
+
+            socket.onAnyOutgoing(() => {
+              success(sio, clientSocket, done);
+            });
+
+            socket.emit("my-event", "123");
+          });
+        });
+      });
+    });
   });
 
   describe("messaging many", () => {
@@ -2516,25 +2712,116 @@ describe("socket.io", () => {
       });
     });
 
-    it("should pre encode a broadcast packet", (done) => {
+    it("should broadcast and expect multiple acknowledgements", (done) => {
       const srv = createServer();
       const sio = new Server(srv);
 
-      srv.listen(() => {
-        const clientSocket = client(srv, { multiplex: false });
+      srv.listen(async () => {
+        const socket1 = client(srv, { multiplex: false });
+        const socket2 = client(srv, { multiplex: false });
+        const socket3 = client(srv, { multiplex: false });
 
-        sio.on("connection", (socket) => {
-          socket.conn.on("packetCreate", (packet) => {
-            expect(packet.data).to.eql('2["hello","world"]');
-            expect(packet.options.wsPreEncoded).to.eql('42["hello","world"]');
+        await Promise.all([
+          waitFor(socket1, "connect"),
+          waitFor(socket2, "connect"),
+          waitFor(socket3, "connect"),
+        ]);
+
+        socket1.on("some event", (cb) => {
+          cb(1);
+        });
+
+        socket2.on("some event", (cb) => {
+          cb(2);
+        });
+
+        socket3.on("some event", (cb) => {
+          cb(3);
+        });
+
+        sio.timeout(2000).emit("some event", (err, responses) => {
+          expect(err).to.be(null);
+          expect(responses).to.have.length(3);
+          expect(responses).to.contain(1, 2, 3);
+
+          done();
+        });
+      });
+    });
+
+    it("should fail when a client does not acknowledge the event in the given delay", (done) => {
+      const srv = createServer();
+      const sio = new Server(srv);
+
+      srv.listen(async () => {
+        const socket1 = client(srv, { multiplex: false });
+        const socket2 = client(srv, { multiplex: false });
+        const socket3 = client(srv, { multiplex: false });
+
+        await Promise.all([
+          waitFor(socket1, "connect"),
+          waitFor(socket2, "connect"),
+          waitFor(socket3, "connect"),
+        ]);
+
+        socket1.on("some event", (cb) => {
+          cb(1);
+        });
+
+        socket2.on("some event", (cb) => {
+          cb(2);
+        });
+
+        socket3.on("some event", (cb) => {
+          // timeout
+        });
+
+        sio.timeout(200).emit("some event", (err, responses) => {
+          expect(err).to.be.an(Error);
+          expect(responses).to.have.length(2);
+          expect(responses).to.contain(1, 2);
+
+          done();
+        });
+      });
+    });
+
+    it("should broadcast and return if the packet is sent to 0 client", (done) => {
+      const srv = createServer();
+      const sio = new Server(srv);
+
+      srv.listen(async () => {
+        const socket1 = client(srv, { multiplex: false });
+        const socket2 = client(srv, { multiplex: false });
+        const socket3 = client(srv, { multiplex: false });
+
+        await Promise.all([
+          waitFor(socket1, "connect"),
+          waitFor(socket2, "connect"),
+          waitFor(socket3, "connect"),
+        ]);
+
+        socket1.on("some event", () => {
+          done(new Error("should not happen"));
+        });
+
+        socket2.on("some event", () => {
+          done(new Error("should not happen"));
+        });
+
+        socket3.on("some event", () => {
+          done(new Error("should not happen"));
+        });
+
+        sio
+          .to("room123")
+          .timeout(200)
+          .emit("some event", (err, responses) => {
+            expect(err).to.be(null);
+            expect(responses).to.have.length(0);
 
-            clientSocket.close();
-            sio.close();
             done();
           });
-
-          sio.emit("hello", "world");
-        });
       });
     });
   });
@@ -2725,6 +3012,25 @@ describe("socket.io", () => {
         if (++count === 2) done();
       });
     });
+
+    it("should only set `connected` to true after the middleware execution", (done) => {
+      const httpServer = createServer();
+      const io = new Server(httpServer);
+
+      const clientSocket = client(httpServer, "/");
+
+      io.use((socket, next) => {
+        expect(socket.connected).to.be(false);
+        expect(socket.disconnected).to.be(true);
+        next();
+      });
+
+      io.on("connection", (socket) => {
+        expect(socket.connected).to.be(true);
+        expect(socket.disconnected).to.be(false);
+        success(io, clientSocket, done);
+      });
+    });
   });
 
   describe("socket middleware", () => {
@@ -2864,4 +3170,6 @@ describe("socket.io", () => {
       });
     });
   });
+
+  require("./socket-timeout");
 });

test/support/util.ts

@@ -1,10 +1,18 @@
+import type { Server } from "../..";
+import {
+  io as ioc,
+  ManagerOptions,
+  Socket as ClientSocket,
+  SocketOptions,
+} from "socket.io-client";
+
 const expect = require("expect.js");
 const i = expect.stringify;
 
 // add support for Set/Map
 const contain = expect.Assertion.prototype.contain;
 expect.Assertion.prototype.contain = function (...args) {
-  if (typeof this.obj === "object") {
+  if (this.obj instanceof Set || this.obj instanceof Map) {
     args.forEach((obj) => {
       this.assert(
         this.obj.has(obj),
@@ -20,3 +28,19 @@ expect.Assertion.prototype.contain = function (...args) {
   }
   return contain.apply(this, args);
 };
+
+export function createClient(
+  io: Server,
+  nsp: string,
+  opts?: ManagerOptions & SocketOptions
+): ClientSocket {
+  // @ts-ignore
+  const port = io.httpServer.address().port;
+  return ioc(`http://localhost:${port}${nsp}`, opts);
+}
+
+export function success(done: Function, io: Server, client: ClientSocket) {
+  io.close();
+  client.disconnect();
+  done();
+}

test/uws.ts

@@ -0,0 +1,197 @@
+import { App, us_socket_local_port } from "uWebSockets.js";
+import { Server } from "..";
+import { io as ioc, Socket as ClientSocket } from "socket.io-client";
+import request from "supertest";
+import expect from "expect.js";
+
+const createPartialDone = (done: (err?: Error) => void, count: number) => {
+  let i = 0;
+  return () => {
+    if (++i === count) {
+      done();
+    } else if (i > count) {
+      done(new Error(`partialDone() called too many times: ${i} > ${count}`));
+    }
+  };
+};
+
+const shouldNotHappen = (done) => () => done(new Error("should not happen"));
+
+describe("socket.io with uWebSocket.js-based engine", () => {
+  let io: Server,
+    port: number,
+    client: ClientSocket,
+    clientWSOnly: ClientSocket,
+    clientPollingOnly: ClientSocket,
+    clientCustomNamespace: ClientSocket;
+
+  beforeEach((done) => {
+    const app = App();
+    io = new Server();
+    io.attachApp(app);
+
+    io.of("/custom");
+
+    app.listen(0, (listenSocket) => {
+      port = us_socket_local_port(listenSocket);
+
+      client = ioc(`http://localhost:${port}`);
+      clientWSOnly = ioc(`http://localhost:${port}`, {
+        transports: ["websocket"],
+      });
+      clientPollingOnly = ioc(`http://localhost:${port}`, {
+        transports: ["polling"],
+      });
+      clientCustomNamespace = ioc(`http://localhost:${port}/custom`);
+    });
+
+    const partialDone = createPartialDone(done, 4);
+    client.on("connect", partialDone);
+    clientWSOnly.on("connect", partialDone);
+    clientPollingOnly.on("connect", partialDone);
+    clientCustomNamespace.on("connect", partialDone);
+  });
+
+  afterEach(() => {
+    io.close();
+    client.disconnect();
+    clientWSOnly.disconnect();
+    clientPollingOnly.disconnect();
+    clientCustomNamespace.disconnect();
+  });
+
+  it("should broadcast", (done) => {
+    const partialDone = createPartialDone(done, 3);
+
+    client.on("hello", partialDone);
+    clientWSOnly.on("hello", partialDone);
+    clientPollingOnly.on("hello", partialDone);
+    clientCustomNamespace.on("hello", shouldNotHappen(done));
+
+    io.emit("hello");
+  });
+
+  it("should broadcast in a namespace", (done) => {
+    client.on("hello", shouldNotHappen(done));
+    clientWSOnly.on("hello", shouldNotHappen(done));
+    clientPollingOnly.on("hello", shouldNotHappen(done));
+    clientCustomNamespace.on("hello", done);
+
+    io.of("/custom").emit("hello");
+  });
+
+  it("should broadcast in a dynamic namespace", (done) => {
+    const dynamicNamespace = io.of(/\/dynamic-\d+/);
+    const dynamicClient = clientWSOnly.io.socket("/dynamic-101");
+
+    dynamicClient.on("connect", () => {
+      dynamicNamespace.emit("hello");
+    });
+
+    dynamicClient.on("hello", () => {
+      dynamicClient.disconnect();
+      done();
+    });
+  });
+
+  it("should broadcast binary content", (done) => {
+    const partialDone = createPartialDone(done, 3);
+
+    client.on("hello", partialDone);
+    clientWSOnly.on("hello", partialDone);
+    clientPollingOnly.on("hello", partialDone);
+    clientCustomNamespace.on("hello", shouldNotHappen(done));
+
+    io.emit("hello", Buffer.from([1, 2, 3]));
+  });
+
+  it("should broadcast volatile packet with binary content", (done) => {
+    const partialDone = createPartialDone(done, 3);
+
+    client.on("hello", partialDone);
+    clientWSOnly.on("hello", partialDone);
+    clientPollingOnly.on("hello", partialDone);
+    clientCustomNamespace.on("hello", shouldNotHappen(done));
+
+    // wait to make sure there are no packets being sent for opening the connection
+    setTimeout(() => {
+      io.volatile.emit("hello", Buffer.from([1, 2, 3]));
+    }, 20);
+  });
+
+  it("should broadcast in a room", (done) => {
+    const partialDone = createPartialDone(done, 2);
+
+    client.on("hello", shouldNotHappen(done));
+    clientWSOnly.on("hello", partialDone);
+    clientPollingOnly.on("hello", partialDone);
+    clientCustomNamespace.on("hello", shouldNotHappen(done));
+
+    io.of("/").sockets.get(clientWSOnly.id)!.join("room1");
+    io.of("/").sockets.get(clientPollingOnly.id)!.join("room1");
+
+    io.to("room1").emit("hello");
+  });
+
+  it("should broadcast in multiple rooms", (done) => {
+    const partialDone = createPartialDone(done, 2);
+
+    client.on("hello", shouldNotHappen(done));
+    clientWSOnly.on("hello", partialDone);
+    clientPollingOnly.on("hello", partialDone);
+    clientCustomNamespace.on("hello", shouldNotHappen(done));
+
+    io.of("/").sockets.get(clientWSOnly.id)!.join("room1");
+    io.of("/").sockets.get(clientPollingOnly.id)!.join("room2");
+
+    io.to(["room1", "room2"]).emit("hello");
+  });
+
+  it("should broadcast in all but a given room", (done) => {
+    const partialDone = createPartialDone(done, 2);
+
+    client.on("hello", partialDone);
+    clientWSOnly.on("hello", partialDone);
+    clientPollingOnly.on("hello", shouldNotHappen(done));
+    clientCustomNamespace.on("hello", shouldNotHappen(done));
+
+    io.of("/").sockets.get(clientWSOnly.id)!.join("room1");
+    io.of("/").sockets.get(clientPollingOnly.id)!.join("room2");
+
+    io.except("room2").emit("hello");
+  });
+
+  it("should work even after leaving room", (done) => {
+    const partialDone = createPartialDone(done, 2);
+
+    client.on("hello", partialDone);
+    clientWSOnly.on("hello", shouldNotHappen(done));
+    clientPollingOnly.on("hello", partialDone);
+    clientCustomNamespace.on("hello", shouldNotHappen(done));
+
+    io.of("/").sockets.get(client.id)!.join("room1");
+    io.of("/").sockets.get(clientPollingOnly.id)!.join("room1");
+
+    io.of("/").sockets.get(clientWSOnly.id)!.join("room1");
+    io.of("/").sockets.get(clientWSOnly.id)!.leave("room1");
+
+    io.to("room1").emit("hello");
+  });
+
+  it("should serve static files", (done) => {
+    const clientVersion = require("socket.io-client/package.json").version;
+
+    request(`http://localhost:${port}`)
+      .get("/socket.io/socket.io.js")
+      .buffer(true)
+      .end((err, res) => {
+        if (err) return done(err);
+        expect(res.headers["content-type"]).to.be("application/javascript");
+        expect(res.headers.etag).to.be('"' + clientVersion + '"');
+        expect(res.headers["x-sourcemap"]).to.be(undefined);
+        expect(res.text).to.match(/engine\.io/);
+        expect(res.status).to.be(200);
+        done();
+      });
+  });
+});