How To Build A Real-Time Commenting System - Practical JavaScript Techniques - page 91

How To Build A Real-Time Commenting System

BY PHIL LEGGETTER ❧

The Web has become increasingly interactive over the years. This trend is set to continue with
the next generation of applications driven by the real-time Web . Adding real-time functionality
to an application can result in a more interactive and engaging user experience. However,
setting up and maintaining the server-side real-time components can be an unwanted
distraction. But don't worry, there is a solution.

Cloud hosted Web services and APIs have come to the rescue of many a developer over the
past few years, and real-time functionality is no different. The focus at Pusher , for example, is

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to let you concentrate on building your real-time Web applications by offering a hosted API
which makes it quick and easy to add scalable real-time functionality to Web and mobile apps.
In this tutorial, I'll show how to convert a basic blog commenting system into a real-time
engaging experience where you'll see a comment made in one browser window "magically"
appear in a second window.

Why Should We Care About The Real-Time Web?

Although the Real-Time Web is a relatively recent mainstream phrase, real-time Web

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technologies have been around for over 10 years. They were mainly used by companies
building software targeted at the financial services sector or in Web chat applications. These
initial solutions were classed as "hacks". In 2006 these solutions were given an umbrella term
called Comet , but even with a defined name the solutions were still considered hacks. So,

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what's changed?

In my opinion there are a number of factors that have moved real-time Web technologies to
the forefront of Web application development.

SOCIAL MEDIA DATA

Social media, and specifically Twitter, has meant that more and more data is becoming
instantly available. Gone are the days where we have to wait an eternity for Google to find our
data (blog posts, status updates, images). There are now platforms that not only make our
data instantly discoverable but also instantly deliver it to those who have declared an interest.
This idea of Publish/Subscribe is core to the real-time Web, especially when building Web

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applications.