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A presentation of Julian Gimbel and Robert Pinsler

Agenda

1

Node.js in a nutshell

2

npm and modules

3

Pros and cons

4

Getting started

1

Node.js in a nutshell

What's Node.js?

platform for building fast, scalable network applications
published 2009 by Ryan Dahl
built on Chrome's V8 JavaScript runtime
applications are written in JavaScript
uses event-driven, non-blocking I/O model

Performance bottleneck

"Please wait..."

Multiple threads

complex manual synchronisation
expensive context switching
high memory consumption

The Node.js way

event-driven + asynchronous, non-blocking I/O

Everything runs in parallel
except your code

Event loop

Callback

				setTimeout(function(){
					console.log("World")
				}, 1000);
			
				console.log('Hello');

Hello world!

			var http = require('http');
			
			http.createServer(function (req, res) {
				res.writeHead(200, {'Content-Type': 'text/plain'});
				res.end('Hello World\n');
			}).listen(1337, '127.0.0.1');
			
			console.log('Server running at http://127.0.0.1:1337/');

Put this into helloworld.js and run:

> node helloworld.js

2

npm and modules

npm

package manager of Node.js
bundled with Node.js as of version 0.6.3

> npm install

> npm adduser, npm publish

Total packages: 73K+

Downloads last week: 67 mio.

Example: debugging

npm install -g node-inspector

node-debug test.js

3

Pros and cons

Pros

performance and scalability
light-weight, low-level
less complex concurrency
platform-independent (available for Mac, Windows, Linux)
JavaScript at client and server
popular and with vibrant community

Cons

JavaScript...
new mindset required
CPU-intensive tasks can block everything
lack of libraries

Usage szenarios

When to use

lots of concurrent requests with few CPU cycles
JSON-based REST services
push-based data connections
streaming

When not to use

CPU-intensive tasks
few interaction with external resources
classical CRUD operations

Companies using Node.js

4

Getting started

How to create a simple HTTP server

Download node.js
> npm install http-server -g
> cd to/presentation/folder
> http-server
Open localhost:8080

Sources

last visited: 18/05/2014

Image sources

last visited: 18/05/2014