Introduction to NodeJS

NodeJS - © Claudio Cicali

What the frak is Node JS?

Tuesday, December 4, 2012


Claudio Cicali

@caludio

Front-end engineer at SponsorPay



Installing NodeJS

Download, unpack, make, make install

... or use homebrew

(and yes! It works on Windows too)



JavaScript is an interpreted languagewhich means that you need an JavaScript

interpreter to run your programs

We often refer to these beastsas JavaScript Engines or

JavaScript Virtual Machine



Every browser has its own VM

Firefox? SpidermonkeyInternet Explorer? Chakra

Chrome? V8Safari? JavaScriptCore

Opera? Carakan

Also Rhino, stand alone



2009: this guy had an idea

(he is Ryan Dahl, btw)



Make no mistake

NodeJS is NOT a “one man project”

It is backed by Joyent, which is a big playerin the cloud computing business

(has money and people)



If you already can write JavaScriptin the browser why can’t you writeJavaScript on the server then?



js VMs are getting better and better

Get one of them, include someadditional libraries and wrap it up

into a powerful, directly executableJavaScript platform



After the idea, the design:

Google V8 would have been the VM(Tried using Spidermonkey, no luck)

Monoprocess, no threads

Completely event driven (asynchronous, non-blocking)

Focus on NETWORKING



What is the “Node Standard Library”?

A set of ready-to-use tools which gives you

- a powerful HTTP(S) library (client and server in no time)- DNS name resolution- Crypto- access to the file system- URL manipulation- ZLIB- UDP datagrams

http://nodejs.org/docs/latest/api/



Those tools can JavaScript onlyor mixed with some C or C++

for performances reason



Now we have a platform to write REAL programs(i.e.: no sandboxing) in JavaScript

The JavaScript itself - oh, joy - it’s the latest stable V8

AND NO COMPATIBILITY LAYER! (cries)

except ...



... except for Node JS itself

With every new major version, you mightloose compatibility at the API level

(the Node standard library)

(this is really more of a youth problem, anyway)



Node JS is fast, in theory

Low maintencance (small impact on resources)

Programs must not stress the CPU

Programming is not THAT easy

API are well documented



The Node JS standard library can be EXTENDED by the use of

modules

This is serious business: the number of available modules is

HUGE

(and the quality? Well...)



MODULES in NodeJS use a well knownpattern/paradigm/standard: CommonJS(which is well known thanks to... NodeJS)

Writing a module is easy

Maybe too much :)

(oh, and you’d write “addons” in C/C++ as well)



Take a look:

https://github.com/joyent/node/wiki/modules





Module management is EASY with

https://npmjs.org/

No need to install it: comes with Node!(Node >= 0.6)

With brew you need to run npmjs.org/install.sh


https://npmjs.org

https://npmjs.org


Need to access MySQL from your program?

npm install mysql



Publishing your module to the worldis freacking easy too

(no moderation, no approval...)

npm publish



Modules can be of any complexity

Connect is a big “middleware” modulewhich gives you cookies, sessions, logging,

caching...

Express is a web framework built on top of Connect



// The “fs” module is ready to usevar fs = require(“fs”);

fs.open(“somefile”, “r”, function(error) {

// Do something with the file

});

What “using modules” means



claudioc$ npm install sqlite

// Once installed the “sqlite” module is// ready to usevar sqlite = require(“sqlite”);

var db = new sqlite.Database();

db.open(“my_db”, function(error) {

// Do something with the database

});



There are libraries which run in the browserAND in NodeJS as modules (transparently)

“As of 3.5.0, YUI runs natively on Node.js and comes with an official npm package for easy installation.”


http://nodejs.org/

http://nodejs.org/

http://search.npmjs.org/#/yui

http://search.npmjs.org/#/yui


What can NodeJS be used for then?

Network servers (HTTP, Proxies, messaging)

API backends

Real time applications

Streaming data

“One page” web sites

Command line tools

BotsTuesday, December 4, 2012




Let me introduce you a coupleof things I’ve done with NodeJS



antipad.comReal time collaborative code editor

Built on the giants’ shoulders:

The ACE editor (awesome)

The ShareJS library (super awesome)

NodeJS (lovely)



jecho

“Poor man” command line remote debuggerfor mobile devices

https://github.com/claudioc/jecho





I want moar!

http://www.nodebeginner.org/(highly recommended)

http://nodetoolbox.com

http://nodeguide.com


http://www.nodebeginner.org

http://www.nodebeginner.org






Follow me! @caludioTuesday, December 4, 2012


One more thing

“The guys that are getting paid the big bucks to deliver scalable solutions aren’t up at night feverishly rewriting their systems in Node. They’re doing what they’ve always done: measuring, testing, benchmarking, thinking hard, keeping up with the academic literature that pertains to their problems.”

-- Alex Payne

http://al3x.net/2010/07/27/node.html




Technology

Introduction to NodeJS