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

Creating a server-side clock


It is sometimes useful to have the date and time from the server side instead of the client side. We're usually interested in the client-side time zone, but this isn't always the case. For example, if we create a dashboard for a web-hosting platform, it could be helpful to display the time as it appears on the server.

In this recipe, we will create a server-side clock that updates the user interface in real time so that we always know what time the server thinks it is.

How to do it…

To create a server-side clock that emits data to the client-side, follow these steps:

  1. First, create a server.js file that emits a new date string every second. To do this, we will set an interval of 1000 ms and emit new Date() for this interval. In JavaScript, when we create new Date() with no arguments, it will always be set to the current date and time, as shown in the following code:

    var express = require('express'),
        app = express(),
        http = require('http'),
        socketIO = require...