Introduction to NodeJS

What the frak is Node JS?

NodeJS - © Claudio Cicali
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 language
which means that you need an JavaScript
interpreter to run your programs

We often refer to these beasts
as JavaScript Engines or
JavaScript Virtual Machine


Every browser has its own VM

Firefox? Spidermonkey
Internet Explorer? Chakra
Chrome? V8
Safari? 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 player
in the cloud computing business
(has money and people)


If you already can write JavaScript
in the browser why can’t you write
JavaScript on the server then?


js VMs are getting better and better

Get one of them, include some
additional libraries and wrap it up
into a powerful, directly executable
JavaScript 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 only
or 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 might
loose 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 known
pattern/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


Need to access MySQL from your program?

npm install mysql


Publishing your module to the world
is freacking easy too
(no moderation, no approval...)

npm publish


Modules can be of any complexity

Connect is a big “middleware” module
which gives you cookies, sessions, logging,
caching...

Express is a web framework built on top of
Connect


What “using modules” means

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

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

// Do something with the file

});


claudioc$ npm install sqlite

// Once installed the “sqlite” module is
// ready to use
var 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 browser
AND 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.”


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

Bots NodeJS - © Claudio Cicali

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


antipad.com
Real 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 debugger
for mobile devices

https://github.com/claudioc/jecho


I want moar!

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

http://nodetoolbox.com

http://nodeguide.com

Follow me! @caludio

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

Introduction to NodeJS

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