2. What’s Node?

3. What’s Node?
Evented I/O for V8 JavaScript

4. Evented I/O
• Don’t wait for I/O to complete
• Instead, do useful stuff on the CPU
• When I/O has finished, execute callback code

5. An Example
File.open('/etc/motd', 'w') do |f|
logger.debug(f.read)
end

6. An Example
fs.readFile '/etc/motd', (err, data) ->
console.log(data) unless err

7. An Example
fs.readFile('/etc/motd', function(err, data) {
if (!err) {
return console.log(data);
}
});

8. Evented I/O
• Prior to Node, no I/O libraries for JavaScript

9. Modules
• Organise functionality
• No interference with other code

10. Loading a module
hello = require('hello')
hello.world()

11. hello.coffee
exports.world = () ->
console.log('Hello World')
hello = require('hello')
hello.world()

12. Listening to Events
hello_world = new HelloWorld()
hello_world.on 'generated', (text) ->
console.log text

13. Emitting Events
class HelloWorld extends EventEmitter
generate: ->
this.emit 'generated', 'Hello World!'
hello_world.on 'generated', (text) ->
console.log text

14. Gems?
• The Node Package Manage (NPM) is awesome
• Find packages at http://search.npmjs.org/
• Node, and packages, are asynchronous by design

15. Consider this
http = require('http');
http.createServer (req, res) ->
respond_later = () ->
res.writeHead 200, {'Content-Type': 'text/plain'}
res.end 'Thank you for waiting 2 secondsn'
setTimeout respond_later, 2000
.listen(1337, "127.0.0.1")

16. Got Speed?
1000 concurrent users
10 requests / user
1 node server
What’s your estimate?

17. Watch it online...
http://vimeo.com/ariejan/jmeter-
benchmark-of-nodejs

18. Got Speed?
1000 concurrent users
10 requests / user
1 node server
Average Response Time: 2007 ms

19. It’s got speed...
... but does it offer quality?

20. Take your vows
• Asynchronous Behaviour Driven Development

21. An example, again...
JSONToolbox.com

22. Honour your vows
API Service
Random password with a negative length of -32
✓ should receive a password of length 32
Random password with a length > 256
✓ should receive a password of length 256
Random password with length 40
✓ should receive a password of length 40
Random password with default length
✓ should receive a valid response
✓ should receive a password of length 12 by default
User agent
✓ should report the user agent string
IP Address
✓ should report client IP address as 127.0.0.1
Ping
✓ should respond with pong
✓ OK » 10 honored (0.087s)

23. Honour your vows
✓ OK » 10 honored (0.087s)

24. Got Ping?
app.get '/api/ping', (req, res) ->
res.contentType('application/json')
res.send { "pong" : true }

25. Enter Zombies
• Headless, full-stack testing
• It’s capybara, but faster
• Oh, of course it’s asynchronous as well

26. Got Pong?
vows
.describe('API Service')
.addBatch
'Ping':
topic: -> zombie.visit("http://127.0.0.1/api/ping", this.callback)
'should respond with pong': (browser) ->
JSON.parse(browser.text('body'))['pong'].should.be.true

27. Useful stuff
• coffee-script - duh!
• express - Sinatra inspired web framework
• socket.io - cross-browser websockets
• vows, zombie - BDD
• nodeunit - TDD / Unit testing
• redis - Fast in memory DB, with PubSub support

28. Link Fest
• http://nodejs.org
• http://vowsjs.org
• http://zombie.labnotes.org
• http://search.npmjs.org
• https://github.com/ariejan/jsontoolbox
• https://github.com/ariejan/apocalypse

29. Q&A

30. Thank you!
Good Night!