Node: Up and Running: Scalable Server-Side Code with JavaScript

202 Pages·2012·8.054 MB·English

by  Tom Hughes-Croucher, Mike Wilson

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Node: Up and Running
Tom Hughes-Croucher and Mike Wilson
Beijing • Cambridge • Farnham • Köln • Sebastopol • Tokyo
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Node: Up and Running
by Tom Hughes-Croucher and Mike Wilson
Copyright © 2012 Tom Hughes-Croucher, Mike Wilson. All rights reserved.
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May 2012: First Edition.
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2012-04-20 First release
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ISBN: 978-1-449-39858-3
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Table of Contents
Foreword by Ryan Dahl ....................................................... vii
Foreword by Brendan Eich ..................................................... ix
Preface ..................................................................... xi
Part I. Up and Running
1. A Very Brief Introduction to Node.js ........................................ 3
Installing Node.js 4
First Steps in Code 7
Node REPL 7
A First Server 9
Why Node? 11
High-Performance Web Servers 11
Professionalism in JavaScript 12
Browser Wars 2.0 13
2. Doing Interesting Things ................................................ 15
Building a Chat Server 15
Let’s Build Twitter 23
3. Building Robust Node Applications ....................................... 33
The Event Loop 33
Patterns 40
The I/O Problem Space 40
Writing Code for Production 45
Error Handling 46
Using Multiple Processors 47
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Part II. Deep Dive and API Reference
4. Core APIs ............................................................. 55
Events 55
EventEmitter 56
Callback Syntax 57
HTTP 59
HTTP Servers 59
HTTP Clients 61
URL 65
querystring 67
I/O 68
Streams 68
Filesystem 69
Buffers 70
console.log 76
5. Helper APIs ........................................................... 77
DNS 77
Crypto 79
Hashing 79
HMAC 81
Public Key Cryptography 82
Processes 86
process Module 86
Child Process 94
Testing Through assert 101
VM 104
6. Data Access .......................................................... 107
NoSQL and Document Stores 107
CouchDB 107
Redis 115
MongoDB 123
Relational Databases 127
MySQL 127
PostgreSQL 134
Connection Pooling 137
MQ Protocols 139
RabbitMQ 140
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7. Important External Modules ............................................ 145
Express 145
A Basic Express App 145
Setting Up Routes in Express 146
Handling Form Data 151
Template Engines 152
Middleware 155
Socket.IO 159
Namespaces 161
Using Socket.IO with Express 163
8. Extending Node ...................................................... 169
Modules 169
Package Manager 169
Searching Packages 170
Creating Packages 170
Publishing Packages 171
Linking 171
Add-ons 172
Glossary ................................................................... 173
Index ..................................................................... 175
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Foreword by Ryan Dahl
In 2008 I was searching for a new programming platform for making websites. This
was more than wanting a new language; indeed, the details of the language mattered
very little to me. Rather, I was concerned about the ability to program advanced push
features into the website like I had seen in Gmail—the ability for the server to push
data to the user instead of having to constantly poll. The existing platforms were tightly
coupled to the idea of the server as something that receives a request and issues a
response sequentially. To push events to the browser, the platform needed to be able
to constantly handle a number of open and mostly idle connections.
I knew how to make this work at the system call layer, in C. If I used only nonblocking
sockets, the overhead per connection was very small. In small tests, I could demonstrate
a server that could handle thousands of idle connections or pretty massive throughput.
I knew that this was the optimal way for a user-space Unix server to be implemented.
However, I didn’t want to work in C; I wanted the beautiful fluidness of a dynamic
language. Although it was possible to issue the exact system calls I wanted in every
programming language, it was very ugly and was always the “alternative” method of
socket programming. My theory was that nonblocking sockets were not actually diffi-
cult at all, as long as everything was nonblocking.
Google announced Chrome and its new JavaScript engine V8 in late 2008. A faster
JavaScript engine made for a faster Web—and V8 made the Web a lot faster. Suddenly
there was this idea of a JavaScript arms race between Google, Apple, Mozilla, and
Microsoft. This, combined with Doug Crockford’s book JavaScript: The Good Parts
(O’Reilly), shifted JavaScript from the language everyone despised to an important
language.
I had an idea: nonblocking sockets in JavaScript! Because JavaScript has no existing
socket libraries, I could be the first to introduce this new and hopefully better interface.
Just take V8 and glue it to my nonblocking C code, and I should be done. I quit my
contracting job and began working on this idea full time. Once I made the very first
version available, I immediately had users who reported bugs; I started fixing those
bugs, and then three years passed.
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It turns out that JavaScript jibes extremely well with nonblocking sockets. This was
not clear from the start. The closures made everything possible. People were able to
build very complex nonblocking servers in just a couple of lines of JavaScript. My initial
fear that the system would be unusably niche was quickly alleviated as hackers from
all over the world began to build libraries for it. The single event loop and pure non-
blocking interface allowed libraries to add more and more complexity without intro-
ducing expensive threads.
In Node, users find a system that scales well by default. Because of the choices made
in the core system, nothing in the system is allowed to do anything too terrible (such
as block the current thread), and thus performance never degrades horribly. It is an
order of magnitude better than the traditional blocking approach, where “better” is
defined as the amount of traffic it can handle.
These days, Node is being used by a large number of startups and established companies
around the world, from Voxer and Uber to Walmart and Microsoft. It’s safe to say that
billions of requests are passing through Node every day. As more and more people
come to the project, the available third-party modules and extensions grow and increase
in quality. Although I was once reserved about recommending it for mission-critical
applications, I now heartily recommend Node for even the most demanding server
systems.
This book gracefully takes the reader through a discussion of and guided exercises for
Node and many third-party modules. By learning the material covered here, you go
from basic familiarity with JavaScript to building complex, interactive websites. If
you’ve used other server-side web frameworks in the past, you’ll be shocked at how
easy it is to build a server in Node.
—Ryan Dahl, creator of Node.js
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