Mastering Node.js E-Book

Sandro Pasquali

• Herausgeber: Packt Publishing
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 428

Veröffentlichungsjahr: 2013

Beschreibung

Node.js is a modern development stack focused on providing an easy way to build scalable network software. Backed by a growing number of large companies and a rapidly increasing developer base, Node is revolutionizing the way that software is being built today. Powered by Google's V8 engine and built out of C++ modules, this is a JavaScript environment for the enterprise.Mastering Node.js will take the reader deep into this exciting development environment. Beginning with a comprehensive breakdown of its innovative non-blocking evented design, Node's structure is explained in detail, laying out how its blazingly fast I/O performance simplifies the creation of fast servers, scalable architectures, and responsive web applications.Mastering Node.js takes you through a concise yet thorough tour of Node's innovative evented non-blocking design, showing you how to build professional applications with the help of detailed examples.Learn how to integrate your applications with Facebook and Twitter, Amazon and Google, creating social apps and programs reaching thousands of collaborators on the cloud. See how the Express and Path frameworks make the creation of professional web applications painless. Set up one, two, or an entire server cluster with just a few lines of code, ready to scale as soon as you're ready to launch. Move data seamlessly between databases and file systems, between clients, and across network protocols, using a beautifully designed, consistent, and predictable set of tools.Mastering Node.js contains all of the examples and explanations you'll need to build applications in a short amount of time and at a low cost, running on a scale and speed that would have been nearly impossible just a few years ago.

Leseprobe

Table of Contents

Mastering Node.js

Credits

About the Author

Acknowledgments

About the Reviewers

www.PacktPub.com

Support files, eBooks, discount offers and more

Why Subscribe?

Free Access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Errata

Piracy

Questions

1. Understanding the Node Environment

Extending JavaScript

Events

Modularity

The Network

V8

Memory and other limits

Harmony

The process object

The Read-Eval-Print Loop and executing a Node program

Summary

2. Understanding Asynchronous Event-Driven Programming

Broadcasting events

Collaboration

Queueing

Listening for events

Signals

Forks

File events

Deferred execution

process.nextTick

setImmediate

Timers

setTimeout

setInterval

unref and ref

Understanding the event loop

Four sources of truth

Callbacks and errors

Conventions

Know your errors

Building pyramids

Considerations

Listening for file changes

Summary

3. Streaming Data Across Nodes and Clients

Exploring streams

Implementing readable streams

Pushing and pulling

Writable streams

Duplex streams

Transforming streams

Using PassThrough streams

Creating an HTTP server

Making HTTP requests

Proxying and tunneling

HTTPS, TLS (SSL), and securing your server

Creating a self-signed certificate for development

Installing a real SSL certificate

The request object

The URL module

The Querystring module

Working with headers

Using cookies

Understanding content types

Handling favicon requests

Handling POST data

Creating and streaming images with Node

Creating, caching, and sending a PNG representation

Summary

4. Using Node to Access the Filesystem

Directories, and iterating over files and folders

Types of files

File paths

File attributes

Opening and closing files

fs.open(path, flags, [mode], callback)

fs.close(fd, callback)

File operations

fs.rename(oldName, newName, callback)

fs.truncate(path, len, callback)

fs.ftruncate(fd, len, callback)

fs.chown(path, uid, gid, callback)

fs.fchown(fd, uid, gid, callback)

fs.lchown(path, uid, gid, callback)

fs.chmod(path, mode, callback)

fs.fchmod(fd, mode, callback)

fs.lchmod(path, mode, callback)

fs.link(srcPath, dstPath, callback)

fs.symlink(srcPath, dstPath, [type], callback)

fs.readlink(path, callback)

fs.realpath(path, [cache], callback)

fs.unlink(path, callback)

fs.rmdir(path, callback)

fs.mkdir(path, [mode], callback)

fs.exists(path, callback)

fs.fsync(fd, callback)

Synchronicity

Moving through directories

Reading from a file

Reading byte by byte

fs.read(fd, buffer, offset, length, position, callback)

Fetching an entire file at once

fs.readFile(path, [options], callback)

Creating a readable stream

fs.createReadStream(path, [options])

Reading a file line by line

The Readline module

Writing to a file

Writing byte by byte

fs.write(fd, buffer, offset, length, position, callback)

Writing large chunks of data

fs.writeFile(path, data, [options], callback)

fs.appendFile(path, data, [options], callback)

Creating a writable stream

fs.createWriteStream(path, [options])

Caveats

Serving static files

Redirecting requests

Location

Content-Location

Implementing resource caching

Handling file uploads

Putting it all together

Summary

5. Managing Many Simultaneous Client Connections

Understanding concurrency

Concurrency is not parallelism

Routing requests

Understanding routes

Using Express to route requests

Using Redis for tracking client state

Storing user data

Handling sessions

Cookies and client state

A simple poll

Centralizing states

Authenticating connections

Basic authentication

Handshaking

Summary

Further reading

6. Creating Real-time Applications

Introducing AJAX

Responding to calls

Creating a stock ticker

Bidirectional communication with Socket.IO

Using the WebSocket API

Socket.IO

Drawing collaboratively

Listening for Server Sent Events

Using the EventSource API

The EventSource stream protocol

Asking questions and getting answers

Building a collaborative document editing application

Summary

7. Utilizing Multiple Processes

Node's single-threaded model

The benefits of single-threaded programming

Multithreading is already native and transparent

Creating child processes

Spawning processes

Forking processes

Buffering process output

Communicating with your child

Sending messages to children

Parsing a file using multiple processes

Using the cluster module

Cluster events

Worker object properties

Worker events

Real-time activity updates of multiple worker results

Summary

8. Scaling Your Application

When to scale?

Network latency

Hot CPUs

Socket usage

Many file descriptors

Data creep

Tools for monitoring servers

Running multiple Node servers

Forward and reverse proxies

Nginx as a proxy

Using HTTP Proxy

Message queues – RabbitMQ

Types of exchanges

Using Node's UDP module

UDP multicasting with Node

Using Amazon Web Services in your application

Authenticating

Errors

Using S3 to store files

Working with buckets

Working with objects

Using AWS with a Node server

Getting and setting data with DynamoDB

Searching the database

Sending mail via SES

Authenticating with Facebook Connect

Summary

9. Testing your Application

Why testing is important

Unit tests

Functional tests

Integration tests

Native Node testing and debugging tools

Writing to the console

Formatting console output

The util.format(format, [arg, arg…]) method

The util.inspect(object, [options]) method

The Node debugger

The assert module

Sandboxing

Distinguishing between local scope and execution context

Using compiled contexts

Errors and exceptions

The domain module

Headless website testing with ZombieJS and Mocha

Mocha

Headless web testing

Using Grunt, Mocha, and PhantomJS to test and deploy projects

Working with Grunt

Summary

A. Organizing Your Work

Loading and using modules

Understanding the module object

Resolving module paths

Using npm

Initializing a package file

Using scripts

Declaring dependencies

Publishing packages

Globally installing packages and binaries

Sharing repositories

B. Introducing the Path Framework

Managing state

Bridging the client/server divide

Sending and receiving

Achieving a modular architecture

C. Creating your own C++ Add-ons

Hello World

Creating a calculator

Implementing callbacks

Closing thoughts

Links and resources

Index

Mastering Node.js

Mastering Node.js

Copyright © 2013 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

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First published: November 2013

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Cover Image by Jarek Blaminsky (<[email protected]>)

Credits

Author

Sandro Pasquali

Reviewers

Alex Kolundzija

Abhijeet Sutar

Kevin Faaborg

Acquisition Editors

Edward Gordan

Gregory Wild

Lead Technical Editor

Sweny M. Sukumaran

Technical Editors

Tanvi Bhatt

Jalasha D'costa

Akashdeep Kundu

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Tarunveer Shetty

Sonali Vernekar

Project Coordinator

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Proofreader

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Graphics

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Production Coordinator

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Cover Work

Kirtee Shingan

About the Author

Sandro Pasquali began writing games on a Commodore PET in grade school, and hasn't looked back. A polyglot programmer, who started with BASIC and assembly, his journey through C, Perl, and PHP led to JavaScript and the browser in 1995. He was immediately hooked on a vision of browsers as the software delivery mechanism of the future. By 1997 he had formed Simple.com, a technology company selling the world's first JavaScript-based application development framework, patenting several technologies and techniques that have proven prescient. Node represents for him only the natural next step in an inevitable march towards the day when all software implementations, and software users, are joined within a collaborative information network.

He has led the design of enterprise-grade applications for some of the largest companies in the world, including Nintendo, Major League Baseball, Bang and Olufsen, LimeWire, and others. He has displayed interactive media exhibits during the Venice Biennial, won design awards, built knowledge management tools for research institutes and schools, and has started and run several startups. Always seeking new ways to blend design excellence and technical innovation, he has made significant contributions across all levels of software architecture, from data management and storage tools to innovative user interfaces and frameworks.

He now works to mentor a new generation of developers also bitten by the collaborative software bug, especially the rabid ones.

Acknowledgments

Many people are responsible for the writing of this book. The team at Packt is owed many thanks for their diligent editing and guidance, not to mention their patience as my work evolved…slowly. Several dear colleagues and friends contributed ideas, feedback, and support. Heartfelt thanks go out to Kevin Faaborg, Michael Nutt, and Ernie Yu, whose insights regarding technology, software, society, and of course Node.js were invaluable in guiding me through the development of this book, and of my work in general. The reinforcing encouragement of Dre Labre, Stuart McDonald, David Furfero, John Politowski, Andy Ross, Alex Gallafent, Paul Griffin, Diana Barnes-Brown, and the others who listened politely while I thought out loud will remain with me as fond memories of this long process. I thank Joseph Werle for his energy and commitment, which was of great help as I grappled with some of the more obscure nuances of the Node.js platform.

In particular I would like to thank Alexander Kolundzija, whose early advocacy began this process, and who is, as T.S. Eliot once said of Ezra Pound, "il miglior fabbro".

The writing of this book kept me away from my family and friends for many days and nights, so I thank them all for putting up with my absences. Most importantly, to my darling wife Elizabeth, who faithfully supported me throughout, I send my love.

About the Reviewers

Kevin Faaborg is a professional software developer and avid software hobbyist. Along with JavaScript and Node.js, his work and interests include event-driven programming, open source software development, and peer-to-peer technology.

Alex Kolundzija is a full stack web developer with over a decade of experience at companies including Google, Meebo, and MLB.com. He's the founder and principal developer of Blend.io, a music collaboration network built with Node.js and a part of the Betaworks Studio of companies.

He has previously reviewed Kito Mann's Java Server Faces in Action (Manning).

Abhijeet Sutar is a computer science graduate from Mumbai University. He is a self-taught software developer, and enthusiastic about learning new technologies. His goto language is Java. He has mainly worked on middleware telephony applications for contact centers. He has also successfully implemented a highly available data store with MongoDB NoSQL database for a contact center application. He is currently moving onto Node.js platform for development of the next generation Operational Technology (OT). He blogs at http://blog.ajduke.in, codes at http://github.com/ajduke and tweets via handle @_ajduke.

I would like to thank the people at Packt Publishing, Krunal, Sweny, for providing reviewing opportunity for new technology, Node. I also want to thank Kranti for providing the chapters and putting reminders on due date, and promptly providing necessary information.

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Preface

The Internet is no longer a collection of static websites to be passively consumed. The browser user has come to expect a much richer, interactive experience. Over the last decade or so, network applications have come to resemble desktop applications. Also, recognition of the social characteristics of information has inspired the development of new kinds of interfaces and visualizations modeling dynamic network states, where the user is viewing change over real time rather than fading snapshots trapped in the past.

Even though our expectations for software have changed, the tools available to us as software developers developers have not changed much. Computers are faster, and multicore chip architectures are common. Data storage is cheaper, as is bandwidth. Yet we continue to develop with tools designed before billion-user websites and push-button management of cloud-based clusters of virtual machines.

The development of network applications remains an overly expensive and slow process because of this. Developers use different languages, programming styles, complicating code maintenance, debugging, and more. Too regularly, scaling issues arrive too early, overwhelming the ability of what is often a small and inexperienced team. Popular modern software features, such as real-time data, multiplayer games, and collaborative editing spaces, demand systems capable of carrying thousands of simultaneous connections without bending. Yet we remain restricted to frameworks designed to assist us in building CRUD applications binding a single relational database on a single server to a single user running a multipage website in a browser on a desktop computer.

Node helps developers build more resilient network applications at scale. Built on C++ and bundled with Google's V8 engine, Node is fast, and it understands JavaScript. Node has brought together the most popular programming language in the world and the fastest JavaScript compiler around, and has given that team easy access to an operating system through C++ bindings. Node represents a change in how network software is designed and built.

What this book covers

Chapter 1, Understanding the Node Environment, gives a brief description of the particular problems Node attempts to solve, with a focus on how its single-threaded event-loop is designed, implemented, and used. We will also learn about how Google's V8 engine can be configured and managed, as well as best practices when building Node programs.

Chapter 2, Understanding Asynchronous Event-Driven Programming, digs deep into the fundamental characteristic of Node's design: event-driven, asynchronous programming. By the end of this chapter you will understand how events, callbacks, and timers are used in Node, as well as how the event loop works to enable high-speed I/O across filesystems, networks, and processes.

Chapter 3, Streaming Data Across Nodes and Clients, describes how streams of I/O data are knitted through most network software, emitted by file servers or broadcast in response to an HTTP GET request. Here we learn how Node facilitates the design, implementation, and composition of network software, using examples of HTTP servers, readable and writable file streams, and other I/O focused Node modules and patterns.

Chapter 4, Using Node to Access the Filesystem, lays out what you need to know when accessing the filesystem with Node, along with techniques for handling file uploads and other networked file operations.

Chapter 5, Managing Many Simultaneous Client Connections, shows you how Node helps in solving problems accompanying the high volume, high concurrency environments that contemporary, collaborative web applications demand. Through examples, learn how to efficiently track user state, route HTTP requests, handle sessions, and authenticate requests using the Redis database and Express web application framework.

Chapter 6, Creating Real-Time Applications, explores AJAX, Server-Sent-Events, and the WebSocket protocol, discussing their pros and cons, and how to implement each using Node. We finish the chapter by building a collaborative document editing application.

Chapter 7, Utilizing Multiple Processes, teaches how to distribute clusters of Node processes across multi-core processors, and other techniques for scaling Node applications. An investigation of the differences between programming in single and multithreaded environments leads to a discussion of how to spawn, fork, and communicate with child processes in Node, and we build an analytics tool that records, and displays, the mouse actions of multiple, simultaneous clients connected through a cluster of web sockets.

Chapter 8, Scaling Your Application, outlines some techniques for detecting when to scale, deciding how to scale, and scaling Node applications across multiple servers and cloud services, with examples including: how to use RabbitMQ as a message queue, using NGINX to proxy Node servers, and using Amazon Web Services in your application.

Chapter 9, Testing Your Application, explains how to implement unit, functional, and integration tests with Node. We will explore several testing libraries, including native Node assertion, sandboxing, and debugging modules. Examples using Grunt, Mocha, PhantomJS, and other build and testing tools accompany the discussion.

Appendix A, Organizing Your Work, gives tips on using the npm package management system. Learn how create packages, publish packages, and manage packages.

Appendix B, Introducing the Path Framework, demonstrates how to use this powerful full-stack application framework to build your next web application using only JavaScript, thanks to Node and its ability to handle thousands of simultaneously connected clients.

Appendix C, Creating Your Own C++ Add-ons, provides a brief introduction on how to build your own C++ add-ons, and how to use them from within Node.

What you need for this book

You will need to have some familiarity with JavaScript, and have a copy of Node installed on your development machine or server, Version 0.10.21 or higher. You should know how to install programs on this machine, as you will need to install Redis, along with other libraries, like PhantomJS. Having Git installed, and learning how to clone GitHub repositories, will greatly improve your experience.

You should install RabbitMQ so that you can follow with the examples using message queues. The sections on using NGINX to proxy Node servers will of course require that you can install and use that web server. To build C++ add-ons you will need to install the appropriate compiler on your system.

The examples in this book are built and tested within UNIX-based environments (including Mac OS X), but you should be able to run all Node examples on Windows-based operating systems as well. You can obtain installers for your system, and binaries, from http://www.nodejs.org.

Who this book is for

This book is for developers who want to build high-capacity network applications, such as social networks, collaborative document editing environments, real time data-driven web interfaces, networked games, and other I/O-heavy software. If you're a client-side JavaScript developer, reading this book will teach you how to become a server-side programmer using a language you already know. If you're a C++ hacker, Node is an open-source project built using that language, offering you an excellent opportunity to make a real impact within a large and growing community, even gaining fame, by helping to develop this exciting new technology.

This book is also for technical managers and others seeking an explanation of the capabilities and design philosophy of Node. The book is filled with examples of how Node solves the problems modern software companies are facing in terms of high-concurrency, real-time applications pushing enormous volumes of data through growing networks. Node has already been embraced by the enterprise, and you should consider it for your next project.

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Summary

In this chapter we've outlined the key problems Node's designers sought to solve, and how their solution has made the creation of easily scalable, high-concurrency networked systems easier for an open community of developers. We've seen how JavaScript has been given very useful new powers, how its evented model has been extended, and how V8 can be configured to further customize the JavaScript runtime.