1.
& Ruby
Saturday, April 17, 2010

2.
@mbleigh
Saturday, April 17, 2010

3.
Saturday, April 17, 2010

4.
present.ly
Saturday, April 17, 2010

5.
What’s Node?
Saturday, April 17, 2010

6.
Evented I/O
for Javascript
Saturday, April 17, 2010

7.
Taking JS Beyond
the Browser
Saturday, April 17, 2010

8.
Runs on
Google’s V8
Saturday, April 17, 2010

9.
var sys = require('sys'),
http = require('http');
http.createServer(function (req, res) {
setTimeout(function () {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello Worldn');
}, 2000);
}).listen(8000);
sys.puts('Server running at http://127.0.0.1:8000/');
Saturday, April 17, 2010

10.
Supported By Node
• HTTP, TCP
• File I/O
• Redis, Mongo, SQL (DBSlayer)
Saturday, April 17, 2010

11.
Express: Node’s Sinatra
• RESTful DSL for Node webapps
• Cookies, sessions, caching, etc.
• expressjs.com
Saturday, April 17, 2010

12.
require.paths.unshift('path/to/express/lib')
require('express')
get('/', function(){
this.redirect('/hello/world')
})
get('/hello/world', function(){
return 'Hello World'
})
run()
Saturday, April 17, 2010

13.
Why Node?
Saturday, April 17, 2010

14.
Generally Speedy
Saturday, April 17, 2010

15.
> summary(node1$ttime)
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.0000 0.0000 1.0000 0.7437 1.0000 106.0000
> summary(thin1$ttime)
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.000 1.000 1.000 1.122 1.000 74.000
> summary(narwhal1$ttime)
Min. 1st Qu. Median Mean 3rd Qu. Max.
15.00 22.00 23.00 23.74 24.00 88.00
> summary(v8cgi1$ttime)
Min. 1st Qu. Median Mean 3rd Qu. Max.
12.00 13.00 13.00 14.49 18.00 39.00
four.livejournal.com/1019177.html
Saturday, April 17, 2010

16.
Great at
Concurrency
Saturday, April 17, 2010

17.
Asynchronous
Everything
Saturday, April 17, 2010

18.
bit.ly/nodejs-fstream
function upload_file(req, res) {
req.setBodyEncoding('binary');
var stream = new multipart.Stream(req);
stream.addListener('part', function(part) {
part.addListener('body', function(chunk) {
var progress = (stream.bytesReceived / stream.bytesTotal *
100).toFixed(2);
var mb = (stream.bytesTotal / 1024 / 1024).toFixed(1);
sys.print("Uploading "+mb+"mb ("+progress+"%)015");
// chunk could be appended to a file if the uploaded file needs to
be saved
});
});
stream.addListener('complete', function() {
res.sendHeader(200, {'Content-Type': 'text/plain'});
res.sendBody('Thanks for playing!');
res.finish();
sys.puts("n=> Done");
});
}
Saturday, April 17, 2010

19.
Javascript is
great for this.
Saturday, April 17, 2010

20.
Browser and server,
together at last
Saturday, April 17, 2010

21.
Why Ruby?
Saturday, April 17, 2010

22.
Are you at the
right conf?
Saturday, April 17, 2010

23.
When to Node
Saturday, April 17, 2010

24.
Real-Time
Applications
Saturday, April 17, 2010

25.
WebSockets
• Persistent server connections
• Part of HTML5
• True real-time for web apps
• Deprecate to Flash Sockets
Saturday, April 17, 2010

26.
Why Real-Time?
• Better on your server
• Better for your user
• You need more buzzwords
Saturday, April 17, 2010

27.
var socket = new WebSocket("ws://www.websocket.org");
socket.onopen = function(evt) { alert("Open."); };
socket.onmessage = function(evt) { alert(evt.data); };
socket.onclose = function(evt) { alert("Closed."); };
socket.send("Hello Web Socket!");
socket.close();
Saturday, April 17, 2010

28.
Why JS for WebSockets?
• You already write your client
interaction code in Javascript
• Just an extension of that
• Same interface throughout
Saturday, April 17, 2010

29.
Hazards of a
Young Tool
Saturday, April 17, 2010

30.
node.websocket.js
• Framework-like approach
• Includes fun examples
• Node version headaches
• github.com/guille/node.websocket.js/
Saturday, April 17, 2010

31.
Socket.IO
• Multi-transport socket for Node
• Comes with client JS library
• For production usage
• github.com/rosepad/socket.io-node
Saturday, April 17, 2010

32.
node.ws.js
• Minimal Node WebSocket server
• Talk to your browser clients
• Javascript all the way down
• Mostly for experimentation
• github.com/ncr/node.ws.js
Saturday, April 17, 2010

33.
How can we
actually use it?
Saturday, April 17, 2010

34.
Redis is the Bridge
• Super-fast, super-awesome
• PUBSUB = WIN!
• Swiss-army knife for your app.
Saturday, April 17, 2010

35.
Example
• Twitter-esque status streams
• Want to update web interface in
real time
• Rails, Node, Redis, and Chrome
Saturday, April 17, 2010

36.
The Ruby Code
Saturday, April 17, 2010

37.
class User < ActiveRecord::Base
# Include default devise modules. Others available are:
# :token_authenticatable, :lockable and :timeoutable
devise :database_authenticatable, :registerable, :rememberable, :validatable
# Setup accessible (or protected) attributes for your model
attr_accessible :email, :password, :password_confirmation
def follow(other_user)
Red.sadd "user:#{other_user.id}:followers", self.id
Red.sadd "user:#{self.id}:follows", other_user.id
end
def follower_ids
Red.smembers "user:#{self.id}:followers"
end
def follow_ids
Red.smembers "user:#{self.id}:follows"
end
def update(text)
(follower_ids + [self.id]).each do |uid|
Red.lpush "user:#{uid}:timeline", text
Red.lpush "user:#{uid}:updates", text
Red.publish "user:#{uid}:timeline", text
end
end
end
Saturday, April 17, 2010

38.
def update(text)
(follower_ids + [self.id]).each do |uid|
Red.lpush "user:#{uid}:timeline", text
Red.lpush "user:#{uid}:updates", text
Red.publish "user:#{uid}:timeline", text
end
end
Saturday, April 17, 2010

39.
The Node Code
Saturday, April 17, 2010

40.
var sys = require("sys"),
ws = require("./ws"),
redis = require("./redis-client");
var pubsub = redis.createClient();
pubsub.stream.addListener('connect', function() {
pubsub.subscribeTo("user:*:timeline", function(channel, data) {
var uid = channel.toString().split(':')[1];
if (clients[uid]) {
sys.debug("Writing " + data + " to " + uid)
clients[uid].write(data);
} else {
sys.debug("User " + clients[uid] + " is not connected.");
}
});
});
ws.createServer(function (websocket) {
var user_id = null;
var websocket = websocket;
websocket.addListener("connect", function (resource) {
user_id = resource.match(/timeline/([0-9]+)$/i)[1]
clients[user_id] = websocket;
}).addListener("close", function() {
sys.debug("User " + user_id + " disconnected.")
});
}).listen(8080);
Saturday, April 17, 2010

41.
ws.createServer(function (websocket) {
var user_id = null;
var websocket = websocket;
websocket.addListener("connect", function (resource) {
user_id = resource.match(/timeline/([0-9]+)$/i)[1]
clients[user_id] = websocket;
}).addListener("close", function() {
sys.debug("User " + user_id + " disconnected.")
});
}).listen(8080);
Saturday, April 17, 2010

42.
pubsub.stream.addListener('connect', function() {
pubsub.subscribeTo("user:*:timeline", function(channel, data) {
var uid = channel.toString().split(':')[1];
if (clients[uid]) {
sys.debug("Writing " + data + " to " + uid)
clients[uid].write(data);
} else {
sys.debug("User " + clients[uid] + " is not connected.");
}
});
});
Saturday, April 17, 2010

43.
The Browser Code
Saturday, April 17, 2010

44.
if ("WebSocket" in window) {
var ws = new WebSocket("ws://127.0.0.1:8080/timeline/" +
current_user);
ws.onmessage = function(evt) {
$('ul.timeline').prepend("<li>" + evt.data + "</li>");
}
}
Saturday, April 17, 2010

45.
How else can we
use Node?
Saturday, April 17, 2010

46.
Asynchronous
Applications
Saturday, April 17, 2010

47.
Push APIs
• Want to notify API subscribers in
real-time
• Utilize Webhooks
• Example: GitHub’s Service Hooks
Saturday, April 17, 2010

48.
Saturday, April 17, 2010

49.
File Transcoding
Saturday, April 17, 2010

50.
Saturday, April 17, 2010

51.
Online Gaming
Saturday, April 17, 2010

52.
Ephemeral
Peer-to-Peer
Saturday, April 17, 2010

53.
Wrapping up...
Saturday, April 17, 2010

54.
Tip of the Iceberg
• Node’s libraries and use cases
are expanding rapidly
• Async means thinking differently
• Still at the early stages
Saturday, April 17, 2010

55.
howtonode.org
Saturday, April 17, 2010

56.
Node for Ruby?
Saturday, April 17, 2010

57.
EventMachine
Saturday, April 17, 2010

58.
Cramp
Saturday, April 17, 2010

59.
Use what feels right.
Saturday, April 17, 2010

60.
I don’t know
the half of it.
Saturday, April 17, 2010

61.
Questions?
Saturday, April 17, 2010