Book Image

Socket.IO Cookbook

By : Tyson Cadenhead
Book Image

Socket.IO Cookbook

By: Tyson Cadenhead

Overview of this book

Socket.IO is a JavaScript library that provides you with the ability to implement real-time analytics, binary streaming, instant messaging, and document collaboration. It has two parts: a client-side library that runs in the browser, and a server-side library for node.js. Socket.IO is event-driven and primarily uses the WebSocket protocol that allows us to emit data bi-directionally from the server and the client. Socket.IO This book is a complete resource, covering topics from webSocket security to scaling the server-side of a Socket.IO application and everything in between. This book will provide real-world examples of how secure bi-directional, full-duplex connections that can be created using Socket.IO for different environments. It will also explain how the connection vulnerabilities can be resolved for large numbers of users and huge amounts of data/messages. By the end of the book, you will be a competent Socket.IO developer. With the help of the examples and real-world solutions,you will learn to create fast, scalable, and dynamic real-time apps by creating efficient messaging systems between the server side and the client side using Socket.IO.
Table of Contents (15 chapters)
Socket.IO Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Locking down the HTTP referrer


Socket.IO is really good at getting around cross-domain issues when you create a request from a client in a different domain than the domain your server lives on. You can easily include the Socket.IO script from a different domain on your page. It will work just as you may expect it to.

There are some instances where you may not want your Socket.IO events to be available to every other domain. Not to worry! We can easily whitelist only the http referrers that we want so that some domains will be allowed to connect and other domains won't.

How to do it…

To lock down the HTTP referrer and only allow events to whitelisted domains, follow these steps:

  1. Create two different servers that can connect to your Socket.IO instance. We will let one server listen on port 5000, and let the second server listen on port 5001:

    var express = require('express'),
           app = express(),
           http = require('http'),
           socketIO = require('socket.io'),
           server, server2, io...