Vanessa Wang - The Definitive Guide to HTML5 WebSocket

The Definitive Guide to HTML5 WebSocket

Vanessa Wang

Frank Salim

Peter Moskovits

Th e Defi nitive Guide to HTML5 WebSocket

Copyright 2013 by Vanessa Wang, Frank Salim, Peter Moskovits

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To Julian, my partner in hijinks.

Vanessa Wang

For everyone working to buid a better Web and a better world.

Frank Salim

To Danka, Lea, and their little and not so little cousins: Gego, Luca, Bence, Aaron, and Noah.

Peter Moskovits

Contents at a Glance

Contents

Foreword

The browser is, hands down, the most popular and ubiquitous deployment platform available to us today: virtually every computer, smartphone, tablet, and just about every other form factor imaginable can now execute JavaScript, render a web page, and of course, talk HTTP. This, on its own, is a remarkable achievement, especially when you realize that it only took us a little over a decade to get to this stage. However, this is also just the beginning. The browser of yesterday looks nothing like what we now have access to thanks to all of the innovations of HTML5.

It is hard to overstate the importance of what HTML5 WebSocket enables: up until now, the browser could only speak one language (HTTP), and that language was not designed for the requirements of the modern, real-time Web. Yes, weve made progress with interim solutions such as long-polling and Flash sockets, but the complexity and cost of these solutions has always limited the capabilities of what we could do. WebSockets changes all of that: it is designed from the ground up to be data agnostic (binary and text), full-duplex, and optimized for minimum overhead, both in bytes and in latency.