chore(release): 3.1.0

Diff: https://github.com/socketio/socket.io/compare/3.0.5...3.1.0

.replit

@@ -0,0 +1,2 @@
+language = "nodejs"
+run = "npm start"

CHANGELOG.md

@@ -1,3 +1,19 @@
+# [3.1.0](https://github.com/socketio/socket.io/compare/3.0.5...3.1.0) (2021-01-15)
+
+
+### Features
+
+* confirm a weak but matching ETag ([#3485](https://github.com/socketio/socket.io/issues/3485)) ([161091d](https://github.com/socketio/socket.io/commit/161091dd4c9e1b1610ac3d45d964195e63d92b94))
+* **esm:** export the Namespace and Socket class ([#3699](https://github.com/socketio/socket.io/issues/3699)) ([233650c](https://github.com/socketio/socket.io/commit/233650c22209708b5fccc4349c38d2fa1b465d8f))
+* add support for Socket.IO v2 clients ([9925746](https://github.com/socketio/socket.io/commit/9925746c8ee3a6522bd640b5d586c83f04f2f1ba))
+* add room events ([155fa63](https://github.com/socketio/socket.io-adapter/commit/155fa6333a504036e99a33667dc0397f6aede25e))
+
+
+### Bug Fixes
+
+* allow integers as event names ([1c220dd](https://github.com/socketio/socket.io-parser/commit/1c220ddbf45ea4b44bc8dbf6f9ae245f672ba1b9))
+
+
 ## [3.0.5](https://github.com/socketio/socket.io/compare/3.0.4...3.0.5) (2021-01-05)
 
 

Readme.md

@@ -1,6 +1,5 @@
-
 # socket.io
-
+[![Run on Repl.it](https://repl.it/badge/github/socketio/socket.io)](https://repl.it/github/socketio/socket.io)
 [![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)
@@ -22,6 +21,8 @@ Some implementations in other languages are also available:
 - [C++](https://github.com/socketio/socket.io-client-cpp)
 - [Swift](https://github.com/socketio/socket.io-client-swift)
 - [Dart](https://github.com/rikulo/socket.io-client-dart)
+- [Python](https://github.com/miguelgrinberg/python-socketio)
+- [.Net](https://github.com/Quobject/SocketIoClientDotNet)
 
 Its main features are:
 

examples/chat/public/main.js

@@ -1,36 +1,36 @@
 $(function() {
-  var FADE_TIME = 150; // ms
-  var TYPING_TIMER_LENGTH = 400; // ms
-  var COLORS = [
+  const FADE_TIME = 150; // ms
+  const TYPING_TIMER_LENGTH = 400; // ms
+  const COLORS = [
     '#e21400', '#91580f', '#f8a700', '#f78b00',
     '#58dc00', '#287b00', '#a8f07a', '#4ae8c4',
     '#3b88eb', '#3824aa', '#a700ff', '#d300e7'
   ];
 
   // Initialize variables
-  var $window = $(window);
-  var $usernameInput = $('.usernameInput'); // Input for username
-  var $messages = $('.messages'); // Messages area
-  var $inputMessage = $('.inputMessage'); // Input message input box
+  const $window = $(window);
+  const $usernameInput = $('.usernameInput'); // Input for username
+  const $messages = $('.messages');           // Messages area
+  const $inputMessage = $('.inputMessage');   // Input message input box
 
-  var $loginPage = $('.login.page'); // The login page
-  var $chatPage = $('.chat.page'); // The chatroom page
+  const $loginPage = $('.login.page');        // The login page
+  const $chatPage = $('.chat.page');          // The chatroom page
+
+  const socket = io();
 
   // Prompt for setting a username
-  var username;
-  var connected = false;
-  var typing = false;
-  var lastTypingTime;
-  var $currentInput = $usernameInput.focus();
-
-  var socket = io();
+  let username;
+  let connected = false;
+  let typing = false;
+  let lastTypingTime;
+  let $currentInput = $usernameInput.focus();
 
   const addParticipantsMessage = (data) => {
-    var message = '';
+    let message = '';
     if (data.numUsers === 1) {
-      message += "there's 1 participant";
+      message += `there's 1 participant`;
     } else {
-      message += "there are " + data.numUsers + " participants";
+      message += `there are ${data.numUsers} participants`;
     }
     log(message);
   }
@@ -53,45 +53,41 @@ $(function() {
 
   // Sends a chat message
   const sendMessage = () => {
-    var message = $inputMessage.val();
+    let message = $inputMessage.val();
     // Prevent markup from being injected into the message
     message = cleanInput(message);
     // if there is a non-empty message and a socket connection
     if (message && connected) {
       $inputMessage.val('');
-      addChatMessage({
-        username: username,
-        message: message
-      });
+      addChatMessage({ username, message });
       // tell server to execute 'new message' and send along one parameter
       socket.emit('new message', message);
     }
   }
 
   // Log a message
-    const log = (message, options) => {
-    var $el = $('<li>').addClass('log').text(message);
+  const log = (message, options) => {
+    const $el = $('<li>').addClass('log').text(message);
     addMessageElement($el, options);
   }
 
   // Adds the visual chat message to the message list
   const addChatMessage = (data, options) => {
     // Don't fade the message in if there is an 'X was typing'
-    var $typingMessages = getTypingMessages(data);
-    options = options || {};
+    const $typingMessages = getTypingMessages(data);
     if ($typingMessages.length !== 0) {
       options.fade = false;
       $typingMessages.remove();
     }
 
-    var $usernameDiv = $('<span class="username"/>')
+    const $usernameDiv = $('<span class="username"/>')
       .text(data.username)
       .css('color', getUsernameColor(data.username));
-    var $messageBodyDiv = $('<span class="messageBody">')
+    const $messageBodyDiv = $('<span class="messageBody">')
       .text(data.message);
 
-    var typingClass = data.typing ? 'typing' : '';
-    var $messageDiv = $('<li class="message"/>')
+    const typingClass = data.typing ? 'typing' : '';
+    const $messageDiv = $('<li class="message"/>')
       .data('username', data.username)
       .addClass(typingClass)
       .append($usernameDiv, $messageBodyDiv);
@@ -119,8 +115,7 @@ $(function() {
   // options.prepend - If the element should prepend
   //   all other messages (default = false)
   const addMessageElement = (el, options) => {
-    var $el = $(el);
-
+    const $el = $(el);
     // Setup default options
     if (!options) {
       options = {};
@@ -141,6 +136,7 @@ $(function() {
     } else {
       $messages.append($el);
     }
+
     $messages[0].scrollTop = $messages[0].scrollHeight;
   }
 
@@ -159,8 +155,8 @@ $(function() {
       lastTypingTime = (new Date()).getTime();
 
       setTimeout(() => {
-        var typingTimer = (new Date()).getTime();
-        var timeDiff = typingTimer - lastTypingTime;
+        const typingTimer = (new Date()).getTime();
+        const timeDiff = typingTimer - lastTypingTime;
         if (timeDiff >= TYPING_TIMER_LENGTH && typing) {
           socket.emit('stop typing');
           typing = false;
@@ -179,12 +175,12 @@ $(function() {
   // Gets the color of a username through our hash function
   const getUsernameColor = (username) => {
     // Compute hash code
-    var hash = 7;
-    for (var i = 0; i < username.length; i++) {
-       hash = username.charCodeAt(i) + (hash << 5) - hash;
+    let hash = 7;
+    for (let i = 0; i < username.length; i++) {
+      hash = username.charCodeAt(i) + (hash << 5) - hash;
     }
     // Calculate color
-    var index = Math.abs(hash % COLORS.length);
+    const index = Math.abs(hash % COLORS.length);
     return COLORS[index];
   }
 
@@ -229,7 +225,7 @@ $(function() {
   socket.on('login', (data) => {
     connected = true;
     // Display the welcome message
-    var message = "Welcome to Socket.IO Chat – ";
+    const message = 'Welcome to Socket.IO Chat – ';
     log(message, {
       prepend: true
     });
@@ -243,13 +239,13 @@ $(function() {
 
   // Whenever the server emits 'user joined', log it in the chat body
   socket.on('user joined', (data) => {
-    log(data.username + ' joined');
+    log(`${data.username} joined`);
     addParticipantsMessage(data);
   });
 
   // Whenever the server emits 'user left', log it in the chat body
   socket.on('user left', (data) => {
-    log(data.username + ' left');
+    log(`${data.username} left`);
     addParticipantsMessage(data);
     removeChatTyping(data);
   });

lib/client.ts

@@ -160,7 +160,7 @@ export class Client {
    * @private
    */
   private close() {
-    if ("open" == this.conn.readyState) {
+    if ("open" === this.conn.readyState) {
       debug("forcing transport close");
       this.conn.close();
       this.onclose("forced server close");
@@ -186,7 +186,7 @@ export class Client {
       }
     }
 
-    if ("open" == this.conn.readyState) {
+    if ("open" === this.conn.readyState) {
       debug("writing packet %j", packet);
       if (!opts.preEncoded) {
         // not broadcasting, need to encode
@@ -220,7 +220,7 @@ export class Client {
    * @private
    */
   private ondecoded(packet: Packet) {
-    if (PacketType.CONNECT == packet.type) {
+    if (PacketType.CONNECT === packet.type) {
       this.connect(packet.nsp, packet.data);
     } else {
       const socket = this.nsps.get(packet.nsp);

lib/index.ts

@@ -100,6 +100,11 @@ interface EngineOptions {
    * the options that will be forwarded to the cors module
    */
   cors: CorsOptions;
+  /**
+   * whether to enable compatibility with Socket.IO v2 clients
+   * @default false
+   */
+  allowEIO3: boolean;
 }
 
 interface AttachOptions {
@@ -432,10 +437,11 @@ export class Server extends EventEmitter {
     // 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.headers["if-none-match"];
     if (etag) {
-      if (expectedEtag == etag) {
+      if (expectedEtag === etag || weakEtag === etag) {
         debug("serve client %s 304", type);
         res.writeHead(304);
         res.end();
@@ -522,7 +528,11 @@ export class Server extends EventEmitter {
    */
   private onconnection(conn): Server {
     debug("incoming connection with id %s", conn.id);
-    new Client(this, conn);
+    const client = new Client(this, conn);
+    if (conn.protocol === 3) {
+      // @ts-ignore
+      client.connect("/");
+    }
     return this;
   }
 

lib/namespace.ts

@@ -135,11 +135,16 @@ export class Namespace extends EventEmitter {
     this.run(socket, (err) => {
       process.nextTick(() => {
         if ("open" == client.conn.readyState) {
-          if (err)
-            return socket._error({
-              message: err.message,
-              data: err.data,
-            });
+          if (err) {
+            if (client.conn.protocol === 3) {
+              return socket._error(err.data || err.message);
+            } else {
+              return socket._error({
+                message: err.message,
+                data: err.data,
+              });
+            }
+          }
 
           // track socket
           this.sockets.set(socket.id, socket);

lib/socket.ts

@@ -105,7 +105,12 @@ export class Socket extends EventEmitter {
     super();
     this.server = nsp.server;
     this.adapter = this.nsp.adapter;
-    this.id = base64id.generateId(); // don't reuse the Engine.IO id because it's sensitive information
+    if (client.conn.protocol === 3) {
+      // @ts-ignore
+      this.id = nsp.name !== "/" ? nsp.name + "#" + client.id : client.id;
+    } 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);
@@ -286,7 +291,11 @@ export class Socket extends EventEmitter {
   _onconnect(): void {
     debug("socket connected - writing packet");
     this.join(this.id);
-    this.packet({ type: PacketType.CONNECT, data: { sid: this.id } });
+    if (this.conn.protocol === 3) {
+      this.packet({ type: PacketType.CONNECT });
+    } else {
+      this.packet({ type: PacketType.CONNECT, data: { sid: this.id } });
+    }
   }
 
   /**

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "socket.io",
-  "version": "3.0.5",
+  "version": "3.1.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -462,6 +462,12 @@
       "integrity": "sha512-K0Ptm/47OKfQRpNQ2J/oIN/3QYiK6FwW+eJbILhsdxh2WTLdl+30o8aGdTbm5JbffpFFAg/g+zi1E+jvJha5ng==",
       "dev": true
     },
+    "after": {
+      "version": "0.8.2",
+      "resolved": "https://registry.npmjs.org/after/-/after-0.8.2.tgz",
+      "integrity": "sha1-/ts5T58OAqqXaOcCvaI7UF+ufh8=",
+      "dev": true
+    },
     "aggregate-error": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/aggregate-error/-/aggregate-error-3.1.0.tgz",
@@ -535,6 +541,12 @@
         "sprintf-js": "~1.0.2"
       }
     },
+    "arraybuffer.slice": {
+      "version": "0.0.7",
+      "resolved": "https://registry.npmjs.org/arraybuffer.slice/-/arraybuffer.slice-0.0.7.tgz",
+      "integrity": "sha512-wGUIVQXuehL5TCqQun8OW81jGzAWycqzFF8lFp+GOM5BXLYj3bKNsYC4daB7n6XjCqxQA/qgTJ+8ANR3acjrog==",
+      "dev": true
+    },
     "astral-regex": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/astral-regex/-/astral-regex-1.0.0.tgz",
@@ -584,6 +596,12 @@
       "resolved": "https://registry.npmjs.org/base64id/-/base64id-2.0.0.tgz",
       "integrity": "sha512-lGe34o6EHj9y3Kts9R4ZYs/Gr+6N7MCaMlIFA3F1R2O5/m7K06AxfSeO5530PEERE6/WyEg3lsuyw4GHlPZHog=="
     },
+    "blob": {
+      "version": "0.0.5",
+      "resolved": "https://registry.npmjs.org/blob/-/blob-0.0.5.tgz",
+      "integrity": "sha512-gaqbzQPqOoamawKg0LGVd7SzLgXS+JH61oWprSLH+P+abTczqJbhTR8CmJ2u9/bUYNmHTGJx/UEmn6doAvvuig==",
+      "dev": true
+    },
     "brace-expansion": {
       "version": "1.1.11",
       "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
@@ -722,11 +740,23 @@
       "integrity": "sha1-3dgA2gxmEnOTzKWVDqloo6rxJTs=",
       "dev": true
     },
+    "component-bind": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/component-bind/-/component-bind-1.0.0.tgz",
+      "integrity": "sha1-AMYIq33Nk4l8AAllGx06jh5zu9E=",
+      "dev": true
+    },
     "component-emitter": {
       "version": "1.3.0",
       "resolved": "https://registry.npmjs.org/component-emitter/-/component-emitter-1.3.0.tgz",
       "integrity": "sha512-Rd3se6QB+sO1TwqZjscQrurpEPIfO0/yYnSin6Q/rD3mOutHvUrCAhJub3r90uNb+SESBuE0QYoB90YdfatsRg=="
     },
+    "component-inherit": {
+      "version": "0.0.3",
+      "resolved": "https://registry.npmjs.org/component-inherit/-/component-inherit-0.0.3.tgz",
+      "integrity": "sha1-ZF/ErfWLcrZJ1crmUTVhnbJv8UM=",
+      "dev": true
+    },
     "concat-map": {
       "version": "0.0.1",
       "resolved": "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz",
@@ -830,9 +860,9 @@
       "dev": true
     },
     "engine.io": {
-      "version": "4.0.6",
-      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-4.0.6.tgz",
-      "integrity": "sha512-rf7HAVZpcRrcKEKddgIzYUnwg0g5HE1RvJaTLwkcfJmce4g+po8aMuE6vxzp6JwlK8FEq/vi0KWN6tA585DjaA==",
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/engine.io/-/engine.io-4.1.0.tgz",
+      "integrity": "sha512-vW7EAtn0HDQ4MtT5QbmCHF17TaYLONv2/JwdYsq9USPRZVM4zG7WB3k0Nc321z8EuSOlhGokrYlYx4176QhD0A==",
       "requires": {
         "accepts": "~1.3.4",
         "base64id": "2.0.0",
@@ -844,9 +874,9 @@
       }
     },
     "engine.io-client": {
-      "version": "4.0.6",
-      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-4.0.6.tgz",
-      "integrity": "sha512-5lPh8rrhxIruo5ZlgFt31KM626o5OCXrCHBweieWWuVicDtnYdz/iR93k6N9k0Xs61WrYxZKIWXzeSaJF6fpNA==",
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-4.1.0.tgz",
+      "integrity": "sha512-OUmn4m71/lW3ixICv4h3DuBRuh3ri0w3cDuepjsrINSbbqbni4Xw1shTFiKhl0v58lEtNpwJTpSKJJ3fondu5Q==",
       "dev": true,
       "requires": {
         "base64-arraybuffer": "0.1.4",
@@ -1314,6 +1344,15 @@
         "function-bind": "^1.1.1"
       }
     },
+    "has-binary2": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/has-binary2/-/has-binary2-1.0.3.tgz",
+      "integrity": "sha512-G1LWKhDSvhGeAQ8mPVQlqNcOB2sJdwATtZKl2pDKKHfpf/rYj24lkinxf69blJbnsvtqqNU+L3SL50vzZhXOnw==",
+      "dev": true,
+      "requires": {
+        "isarray": "2.0.1"
+      }
+    },
     "has-cors": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/has-cors/-/has-cors-1.1.0.tgz",
@@ -1376,6 +1415,12 @@
       "integrity": "sha512-EdDDZu4A2OyIK7Lr/2zG+w5jmbuk1DVBnEwREQvBzspBJkCEbRa8GxU1lghYcaGJCnRWibjDXlq779X1/y5xwg==",
       "dev": true
     },
+    "indexof": {
+      "version": "0.0.1",
+      "resolved": "https://registry.npmjs.org/indexof/-/indexof-0.0.1.tgz",
+      "integrity": "sha1-gtwzbSMrkGIXnQWrMpOmYFn9Q10=",
+      "dev": true
+    },
     "inflight": {
       "version": "1.0.6",
       "resolved": "https://registry.npmjs.org/inflight/-/inflight-1.0.6.tgz",
@@ -1440,6 +1485,12 @@
       "integrity": "sha512-eXK1UInq2bPmjyX6e3VHIzMLobc4J94i4AWn+Hpq3OU5KkrRC96OAcR3PRJ/pGu6m8TRnBHP9dkXQVsT/COVIA==",
       "dev": true
     },
+    "isarray": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/isarray/-/isarray-2.0.1.tgz",
+      "integrity": "sha1-o32U7ZzaLVmGXJ92/llu4fM4dB4=",
+      "dev": true
+    },
     "isexe": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/isexe/-/isexe-2.0.0.tgz",
@@ -2202,23 +2253,115 @@
       }
     },
     "socket.io-adapter": {
-      "version": "2.0.3",
-      "resolved": "https://registry.npmjs.org/socket.io-adapter/-/socket.io-adapter-2.0.3.tgz",
-      "integrity": "sha512-2wo4EXgxOGSFueqvHAdnmi5JLZzWqMArjuP4nqC26AtLh5PoCPsaRbRdah2xhcwTAMooZfjYiNVNkkmmSMaxOQ=="
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/socket.io-adapter/-/socket.io-adapter-2.1.0.tgz",
+      "integrity": "sha512-+vDov/aTsLjViYTwS9fPy5pEtTkrbEKsw2M+oVSoFGw6OD1IpvlV1VPhUzNbofCQ8oyMbdYJqDtGdmHQK6TdPg=="
     },
     "socket.io-client": {
-      "version": "3.0.5",
-      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-3.0.5.tgz",
-      "integrity": "sha512-NNnv3UH5h+aICeVDAdSHll3vSujp1OnzvDtuVz1ukUXliffr1+LTGc1W+qZAm3H7McapGsJhTI5nsBoY1r21dQ==",
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-3.1.0.tgz",
+      "integrity": "sha512-T4qPOL80KnoBwkdR70zMpiR6aH6zv3ZqLNriofHqsO9wvQllNTOez0mpV4GdVqo1Y55Z+h8YOlBo7c8pOxDlHw==",
       "dev": true,
       "requires": {
         "@types/component-emitter": "^1.2.10",
         "backo2": "~1.0.2",
         "component-emitter": "~1.3.0",
         "debug": "~4.3.1",
-        "engine.io-client": "~4.0.6",
+        "engine.io-client": "~4.1.0",
         "parseuri": "0.0.6",
-        "socket.io-parser": "~4.0.3"
+        "socket.io-parser": "~4.0.4"
+      },
+      "dependencies": {
+        "socket.io-parser": {
+          "version": "4.0.4",
+          "resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-4.0.4.tgz",
+          "integrity": "sha512-t+b0SS+IxG7Rxzda2EVvyBZbvFPBCjJoyHuE0P//7OAsN23GItzDRdWa6ALxZI/8R5ygK7jAR6t028/z+7295g==",
+          "dev": true,
+          "requires": {
+            "@types/component-emitter": "^1.2.10",
+            "component-emitter": "~1.3.0",
+            "debug": "~4.3.1"
+          }
+        }
+      }
+    },
+    "socket.io-client-v2": {
+      "version": "npm:socket.io-client@2.4.0",
+      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-2.4.0.tgz",
+      "integrity": "sha512-M6xhnKQHuuZd4Ba9vltCLT9oa+YvTsP8j9NcEiLElfIg8KeYPyhWOes6x4t+LTAC8enQbE/995AdTem2uNyKKQ==",
+      "dev": true,
+      "requires": {
+        "backo2": "1.0.2",
+        "component-bind": "1.0.0",
+        "component-emitter": "~1.3.0",
+        "debug": "~3.1.0",
+        "engine.io-client": "~3.5.0",
+        "has-binary2": "~1.0.2",
+        "indexof": "0.0.1",
+        "parseqs": "0.0.6",
+        "parseuri": "0.0.6",
+        "socket.io-parser": "~3.3.0",
+        "to-array": "0.1.4"
+      },
+      "dependencies": {
+        "debug": {
+          "version": "3.1.0",
+          "resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
+          "integrity": "sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==",
+          "dev": true,
+          "requires": {
+            "ms": "2.0.0"
+          }
+        },
+        "engine.io-client": {
+          "version": "3.5.0",
+          "resolved": "https://registry.npmjs.org/engine.io-client/-/engine.io-client-3.5.0.tgz",
+          "integrity": "sha512-12wPRfMrugVw/DNyJk34GQ5vIVArEcVMXWugQGGuw2XxUSztFNmJggZmv8IZlLyEdnpO1QB9LkcjeWewO2vxtA==",
+          "dev": true,
+          "requires": {
+            "component-emitter": "~1.3.0",
+            "component-inherit": "0.0.3",
+            "debug": "~3.1.0",
+            "engine.io-parser": "~2.2.0",
+            "has-cors": "1.1.0",
+            "indexof": "0.0.1",
+            "parseqs": "0.0.6",
+            "parseuri": "0.0.6",
+            "ws": "~7.4.2",
+            "xmlhttprequest-ssl": "~1.5.4",
+            "yeast": "0.1.2"
+          }
+        },
+        "engine.io-parser": {
+          "version": "2.2.1",
+          "resolved": "https://registry.npmjs.org/engine.io-parser/-/engine.io-parser-2.2.1.tgz",
+          "integrity": "sha512-x+dN/fBH8Ro8TFwJ+rkB2AmuVw9Yu2mockR/p3W8f8YtExwFgDvBDi0GWyb4ZLkpahtDGZgtr3zLovanJghPqg==",
+          "dev": true,
+          "requires": {
+            "after": "0.8.2",
+            "arraybuffer.slice": "~0.0.7",
+            "base64-arraybuffer": "0.1.4",
+            "blob": "0.0.5",
+            "has-binary2": "~1.0.2"
+          }
+        },
+        "ms": {
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/ms/-/ms-2.0.0.tgz",
+          "integrity": "sha1-VgiurfwAvmwpAd9fmGF4jeDVl8g=",
+          "dev": true
+        },
+        "socket.io-parser": {
+          "version": "3.3.2",
+          "resolved": "https://registry.npmjs.org/socket.io-parser/-/socket.io-parser-3.3.2.tgz",
+          "integrity": "sha512-FJvDBuOALxdCI9qwRrO/Rfp9yfndRtc1jSgVgV8FDraihmSP/MLGD5PEuJrNfjALvcQ+vMDM/33AWOYP/JSjDg==",
+          "dev": true,
+          "requires": {
+            "component-emitter": "~1.3.0",
+            "debug": "~3.1.0",
+            "isarray": "2.0.1"
+          }
+        }
       }
     },
     "socket.io-parser": {
@@ -2408,6 +2551,12 @@
       "integrity": "sha1-f17oI66AUgfACvLfSoTsP8+lcLQ=",
       "dev": true
     },
+    "to-array": {
+      "version": "0.1.4",
+      "resolved": "https://registry.npmjs.org/to-array/-/to-array-0.1.4.tgz",
+      "integrity": "sha1-F+bBH3PdTz10zaek/zI46a2b+JA=",
+      "dev": true
+    },
     "to-fast-properties": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/to-fast-properties/-/to-fast-properties-2.0.0.tgz",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "socket.io",
-  "version": "3.0.5",
+  "version": "3.1.0",
   "description": "node.js realtime framework server",
   "keywords": [
     "realtime",
@@ -49,8 +49,8 @@
     "accepts": "~1.3.4",
     "base64id": "~2.0.0",
     "debug": "~4.3.1",
-    "engine.io": "~4.0.6",
-    "socket.io-adapter": "~2.0.3",
+    "engine.io": "~4.1.0",
+    "socket.io-adapter": "~2.1.0",
     "socket.io-parser": "~4.0.3"
   },
   "devDependencies": {
@@ -63,7 +63,8 @@
     "nyc": "^15.1.0",
     "prettier": "^2.2.0",
     "rimraf": "^3.0.2",
-    "socket.io-client": "3.0.5",
+    "socket.io-client": "3.1.0",
+    "socket.io-client-v2": "npm:socket.io-client@^2.4.0",
     "superagent": "^6.1.0",
     "supertest": "^6.0.1",
     "ts-node": "^9.0.0",

test/socket.io.ts

@@ -8,11 +8,11 @@ import { exec } from "child_process";
 import request from "supertest";
 import expect from "expect.js";
 import type { AddressInfo } from "net";
+import * as io_v2 from "socket.io-client-v2";
 
 const ioc = require("socket.io-client");
 
 import "./support/util";
-import exp = require("constants");
 
 // Creates a socket.io client for the given server
 function client(srv, nsp?: string | object, opts?: object) {
@@ -26,6 +26,18 @@ function client(srv, nsp?: string | object, opts?: object) {
   return ioc(url, opts);
 }
 
+const success = (sio, clientSocket, done) => {
+  sio.close();
+  clientSocket.close();
+  done();
+};
+
+const waitFor = (emitter, event) => {
+  return new Promise((resolve) => {
+    emitter.once(event, resolve);
+  });
+};
+
 describe("socket.io", () => {
   it("should be the same version as client", () => {
     const version = require("../package").version;
@@ -116,6 +128,19 @@ describe("socket.io", () => {
           });
       });
 
+      it("should handle 304", (done) => {
+        const srv = createServer();
+        new Server(srv);
+        request(srv)
+          .get("/socket.io/socket.io.js")
+          .set("If-None-Match", 'W/"' + clientVersion + '"')
+          .end((err, res) => {
+            if (err) return done(err);
+            expect(res.statusCode).to.be(304);
+            done();
+          });
+      });
+
       it("should not serve static files", (done) => {
         const srv = createServer();
         new Server(srv, { serveClient: false });
@@ -2430,4 +2455,48 @@ describe("socket.io", () => {
       });
     });
   });
+
+  describe("v2 compatibility", () => {
+    it("should connect if `allowEIO3` is true", (done) => {
+      const srv = createServer();
+      const sio = new Server(srv, {
+        allowEIO3: true,
+      });
+
+      srv.listen(async () => {
+        const port = (srv.address() as AddressInfo).port;
+        const clientSocket = io_v2.connect(`http://localhost:${port}`, {
+          multiplex: false,
+        });
+
+        const [socket]: Array<any> = await Promise.all([
+          waitFor(sio, "connection"),
+          waitFor(clientSocket, "connect"),
+        ]);
+
+        expect(socket.id).to.eql(clientSocket.id);
+        success(sio, clientSocket, done);
+      });
+    });
+
+    it("should not connect if `allowEIO3` is false (default)", (done) => {
+      const srv = createServer();
+      const sio = new Server(srv);
+
+      srv.listen(() => {
+        const port = (srv.address() as AddressInfo).port;
+        const clientSocket = io_v2.connect(`http://localhost:${port}`, {
+          multiplex: false,
+        });
+
+        clientSocket.on("connect", () => {
+          done(new Error("should not happen"));
+        });
+
+        clientSocket.on("connect_error", () => {
+          success(sio, clientSocket, done);
+        });
+      });
+    });
+  });
 });

wrapper.mjs

@@ -1,3 +1,3 @@
 import io from "./dist/index.js";
 
-export const Server = io.Server;
+export const {Server, Namespace, Socket} = io;