Chat example using Cluster + Redis Adapter

examples/chat-cluster/README.md

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+
+# Socket.IO Chat
+
+A simple chat demo for socket.io
+
+## How to use
+
+
+### Starting Redis
+This example uses Redis for communication between sockets that may be connected on different slave processes of the Node application.  
+
+To install `redis-server` follow http://redis.io/topics/quickstart
+
+Run redis with the default configuration. It will run on localhost port 6379.  This runs Redis in the foreground so keep this Terminal window open.
+
+```
+$ redis-server
+```
+
+### Running the example application
+
+```
+$ cd socket.io
+$ npm install
+$ cd examples/chat-cluster
+$ npm install
+$ node .
+```
+
+And point your browser to `http://localhost:3000`. Optionally, specify
+a port by supplying the `PORT` env variable.
+
+## Cluster Chat Features
+
+- Forks the node process multiple times and routes requests to one of the slave processes of Node.
+
+
+## Basic Chat Features (See other example)
+
+- Multiple users can join a chat room by each entering a unique username
+on website load.
+- Users can type chat messages to the chat room.
+- A notification is sent to all users when a user joins or leaves
+the chatroom.

examples/chat-cluster/index.js

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+// Setup basic express server
+var express = require('express');
+var app = express();
+// var server = require('http').createServer(app);
+var http = require('http');
+var port = process.env.PORT || 3000
+
+// Required for cluster
+var redisAdapter = require('socket.io-redis');
+var sticky = require('sticky-session');
+var redis = require('redis');
+var cluster = require('cluster');
+
+// number of slaves
+var workers = process.env.WORKERS || 5;   // use 5 slaves if no number of works is specified
+
+
+///////////////////////////////////
+//      Server
+//
+// Configure sticky sessions to ensure requests go to the same
+// child in the cluster.
+// See : https://github.com/indutny/sticky-session
+// NOTE: Sticky sessions are based on a hash of the IP address. 
+// This means multiple web browsers or tabs on the same machine 
+// will always hit the same slave.
+//
+///////////////////////////////////
+
+sticky(workers, function() {
+
+  // This code will be executed only in slave workers
+  var server = http.createServer(app);
+
+  var io = require('../..')(server);
+  //var io = require('socket.io')(server);
+
+  // configure socket.io to use redis adapter
+  addRedisAdapter(io);
+
+  // configure socket.io to respond to certain events
+  addIOEventHandlers(io);
+
+  return server;
+
+}).listen(port, function() {
+
+  // this code is executed in both slaves and master
+  console.log('server started on port '+port+'. process id = '+process.pid);
+
+});
+
+
+///////////////////////////////////
+//      Routing
+///////////////////////////////////
+
+app.use(express.static(__dirname + '/public'));
+
+
+///////////////////////////////////
+//      Redis Adapter
+///////////////////////////////////
+
+function addRedisAdapter(io) {
+  var redisUrl = process.env.REDISTOGO_URL || 'redis://127.0.0.1:6379';
+  var redisOptions = require('parse-redis-url')(redis).parse(redisUrl);
+  var pub = redis.createClient(redisOptions.port, redisOptions.host, {
+    detect_buffers: true,
+    auth_pass: redisOptions.password
+  });
+  var sub = redis.createClient(redisOptions.port, redisOptions.host, {
+    detect_buffers: true,
+    auth_pass: redisOptions.password
+  });
+
+  io.adapter(redisAdapter({
+    pubClient: pub,
+    subClient: sub
+  }));
+  console.log('Redis adapter started with url: ' + redisUrl);
+};
+
+///////////////////////////////////
+//      Chatroom Handlers
+///////////////////////////////////
+
+// usernames which are currently connected to the chat
+// var usernames = {};
+// var numUsers = 0;
+
+function addIOEventHandlers(io) {
+
+  io.on('connection', function (socket) {
+
+    // var addedUser = false;
+    console.log('Connection made. socket.id='+socket.id+' . pid = '+process.pid);
+
+    // when the client emits 'new message', this listens and executes
+    socket.on('new message', function (data) {
+      // we tell the client to execute 'new message'
+
+      console.log('emitting message: "'+data+'". socket.id='+socket.id+' . pid = '+process.pid);
+      socket.broadcast.emit('new message', {
+        username: socket.username,
+        message: data
+      });
+    });
+
+    // when the client emits 'add user', this listens and executes
+    socket.on('add user', function (username) {
+      // we store the username in the socket session for this client
+      socket.username = username;
+      // add the client's username to the global list
+      // usernames[username] = username;
+      // ++numUsers;
+      // addedUser = true;
+      socket.emit('login', {  // todo
+        numUsers: 420
+      });
+      // echo globally (all clients) that a person has connected
+      socket.broadcast.emit('user joined', {  // todo
+        username: socket.username,
+        numUsers: 421
+      });
+    });
+
+    // when the client emits 'typing', we broadcast it to others
+    socket.on('typing', function () {
+      socket.broadcast.emit('typing', {
+        username: socket.username
+      });
+    });
+
+    // when the client emits 'stop typing', we broadcast it to others
+    socket.on('stop typing', function () {
+      socket.broadcast.emit('stop typing', {
+        username: socket.username
+      });
+    });
+
+    // when the user disconnects.. perform this
+    socket.on('disconnect', function () {
+      socket.broadcast.emit('user left', {  // todo
+        username: socket.username,
+        numUsers: 422
+      });
+    });
+
+  });
+
+};

examples/chat-cluster/package.json

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+{
+  "name": "socket.io-chat",
+  "version": "0.0.0",
+  "description": "A simple chat client using socket.io",
+  "main": "index.js",
+  "author": "Grant Timmerman",
+  "private": true,
+  "license": "BSD",
+  "dependencies": {
+    "express": "3.4.8",
+    "parse-redis-url": "0.0.1",
+    "redis": "^0.12.1",
+    "socket.io-redis": "^0.1.3",
+    "sticky-session": "^0.1.0"
+  }
+}

examples/chat-cluster/public/index.html

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+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <title>Socket.IO Chat Example</title>
+  <link rel="stylesheet" href="style.css">
+</head>
+<body>
+  <ul class="pages">
+    <li class="chat page">
+      <div class="chatArea">
+        <ul class="messages"></ul>
+      </div>
+      <input class="inputMessage" placeholder="Type here..."/>
+    </li>
+    <li class="login page">
+      <div class="form">
+        <h3 class="title">What's your nickname?</h3>
+        <input class="usernameInput" type="text" maxlength="14" />
+      </div>
+    </li>
+  </ul>
+
+  <script src="https://code.jquery.com/jquery-1.10.2.min.js"></script>
+  <script src="/socket.io/socket.io.js"></script>
+  <script src="/main.js"></script>
+</body>
+</html>