This document introduces Node.js, a JavaScript runtime built on Chrome's V8 JavaScript engine. It is well-suited for data-intensive and real-time applications due to its asynchronous and event-driven nature. The document discusses Node.js architecture including its package manager npm and common modules like Express and Socket.io. It provides examples of HTTP, TCP and WebSocket servers in Node.js and demonstrates how to implement routing, templating and websockets applications.

1. Jugando con
websockets en
Israel Gutiérrez

2. NodeJS
• Server side JavaScript
• Platform built over Chrome’s v8
• Event driven (asynchronous)
• Applications
• Data-intensive (efficiency)
• Real-time (websockets)

3. NodeJS architecture

4. npm
• node package manager
• express (routing)
• socket.io (websockets)
• mongo (database drivers)
• ...

5. Application stack
• HTTP server (or TCP-socket or
websockets)
• Router
• Request handlers
• Handle data received
• View logic

6. HTTP server
var http = require("http");
http.createServer(function(request, response) {
response.writeHead(200, {"Content-Type": "text/plain"});
response.write("Hello World");
response.end();
}).listen(8888);

7. TCP server
var net = require('net');
var server = net.createServer(function (socket) {
socket.write('Echo serverrn');
socket.pipe(socket);
});
server.listen(1337, '127.0.0.1');

8. Modules
server.js
var http = require("http");
function start() {
function onRequest(request, response) {
console.log("Request received.");
response.writeHead(200, {"Content-Type": "text/plain"});
response.write("Hello World");
response.end();
}
http.createServer(onRequest).listen(8888);
console.log("Server has started.");
}
exports.start = start;
index.js
var server = require("./server");
server.start();

9. Router and handlers
• You can program the routes based on
request.url
var server = require("./server");
var router = require("./router");
var requestHandlers = require("./requestHandlers");
var handle = {}
handle["/"] = requestHandlers.start;
handle["/start"] = requestHandlers.start;
handle["/upload"] = requestHandlers.upload;
server.start(router.route, handle);
• I recommend using express (Sinatra like)

10. Templating
• ejs
• underscore
• jade
• ...

11. Websockets
• Canal de comunicación full duplex
(bidireccional y a la vez) sobre TCP
• No hay cabeceras HTTP! (menos
overhead)
• Aplicaciones que requieren interacciones
en tiempo real
• URL tipo ws://

12. socket.io
• Websockets library
• Fallbacks
• Flash
• AJAX long polling
• AJAX multipart streaming
• Forever iframe
• JSONP polling

13. socket.io support
Desktop
• Internet Explorer 5.5+
• Safari 3+
• Google Chrome 4+
• Firefox 3+
• Opera 10.61+
Mobile
• iPhone Safari
• iPad Safari
• Android WebKit
• WebOs WebKit

14. socket.io example
Server
var io = require('socket.io').listen(80);
io.sockets.on('connection', function (socket) {
socket.emit('news', { hello: 'world' });
socket.on('my other event', function (data) {
console.log(data);
});
});
Client
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost');
socket.on('news', function (data) {
console.log(data);
socket.emit('my other event', { my: 'data' });
});
</script>

15. References
• http://nodejs.org/
• http://www.nodebeginner.org/
• https://npmjs.org/
• http://socket.io/
• http://www.nodecloud.org/

16. Let’s do some fucking
code!!!