1. Introduction to Node.js
By
Arun Kumar Arjunan,
Product Architect,
Chronus

2. AGENDA
• About Node.js
• Programming in Node.js
• Web Frameworks
• Node.js internals
• Popularity of Node.js
• Downside of Node.js

3. ABOUT NODE.JS
What is
Node.js?

4. ABOUT NODE.JS
Node.js
Applications

5. node.js KO

6. NIDE

7. Chess@home

8. GITJS
GitJS is a pure JavaScript implementation
Of Git.
Example Commands:
• git.js log
• git.js branch
• git.js show SHA

9. NODECHAT

10. DEFINITION
Node.js is an
event-driven I/O
server-side
JavaScript environment

11. AGENDA
• About Node.js
 Programming in Node.js
• Web Frameworks
• Node.js internals
• Popularity of Node.js
• Downside of Node.js

12. HELLO WORLD PROGRAM
Node.JS is a command line tool
$ node hello-console.js

13. HTTP SERVER

14. FILE SYSTEM

15. OTHER LIBRARIES
• Timers • DNS
• Events • REPL
• Buffers • Child Processes
• Streams • ZLIB
• Crypto • OS
• TLS/SSL

16. NODE IS EVENT DRIVEN
Did you notice that the previous
examples use Event Driven
technique?

17. NODE IS EVENT DRIVEN

18. NODE IS EVENT DRIVEN

19. NODE IS EVENT DRIVEN
$ ab –n 200 -c 50 http://localhost:8080/

20. NOW IN RUBY
require 'rubygems'
require 'mongrel'
class HelloWorldHandler < Mongrel::HttpHandler
def process(request, response)
sleep a2
response.start(200) do |head,out|
head["Content-Type"] = "text/plain"
out.write(“Hello World”)
end
end
end
h = Mongrel::HttpServer.new("127.0.0.1", "1337")
h.register("/", HelloWorldHandler.new)
h.run.join
$ ab –n 200 -c 50 http://localhost:1337/

21. EVENT DRIVEN VS THREADING
Lets compare Event Driven Programming
& Thread based programming!!!
• Some theory proves Threading model is better
• Some proves Event Driven Programming is better

22. EVENT DRIVEN VS THREADING
Lets take an example that is
relevant to us!!!

23. APACHE VS NGINX

24. APACHE VS NGINX

25. APACHE VS NGINX
The difference?
Apache uses one thread per
connection.
NGINX doesn’t use threads. It uses
an event loop

26. Disadvantages of Threading
• Context switching is not free
• Execution stacks take up
memory
• For massive concurrency,
cannot use an OS thread for
each connection.

27. AGENDA
• About Node.js
• Programming in Node.js
 Web Frameworks
• Node.js internals
• Popularity of Node.js
• Downside of Node.js

28. NODE.JS COMMUNITY
Node.js
has excellent
community

29. NODE PACKAGE MANAGER
NPM
Its like bundler for Ruby Gems

30. AROUND 60 TEMPLATE ENGINES
asyncEJS, bake, bind-js, blue, CoffeeKup, combyne.js,
doT.js, dust, Eco, ejs, haml.js, haml-js, jshtml, jqtpl,
Jade, jazz, JinJS, JSON Template, jm, jsdom, less.js,
Liquor, minimal.js, Mu, nTPL, nodejs-meta-templates,
normal-template, nun, node.magic_dom, node-template,
node-properties, Parrot, PURE, stencil, Node-T, Swig,
Templ8, template.node.js, tmpl-node, TwigJS, weld

31. WEB FRAMWEORKS
1. Geddy
2. ExpressJS
3. RailwayJS

32. RAILWAYJS
Quick guide to
RailwayJS
Its like Rails itself

33. ROUTES IN RAILWAYJS

34. CONTROLLERS IN RAILWAYJS

35. MODELS IN RAILWAYJS

36. AGENDA
• About Node.js
• Programming in Node.js
• Web Frameworks
• Node.js Internals
• Popularity of Node.js
• Downside of Node.js

37. NODE.JS ARCHITECTURE

38. ABOUT V8
• V8 team is led by Lars Bak
• Lars Bak was the technical lead behind HotSpot (Sun’s
Java VM).
• HotSpot improved Java’s performance 20x times
• Before HotSpot Lars Bak worked on a Smalltalk VM
• V8 uses hidden classes

39. UNDERSTANDING V8
Lets try to
understand V8

40. UNDERSTANDING V8
• It is used to run JavaScript
• Can be embedded into any application
• Can expose C methods & Objects using
JS interface

41. USING V8

42. USING V8
String::New(“a = 1; b = 2; a + b”)
$ ./hello-world
String::New(ARGV[1])
$./hello-world “a = 1; b = 2; a + b”
String::New(fread(ARGV[1]))
$./hello-world hello-world.js

43. NODE.JS ADVANTAGES
So Node.Js is nothing but a set
of libraries using V8 engine

44. AGENDA
• About Node.js
• Programming in Node.js
• Web Frameworks
• Node.js Internals
• Popularity of Node.js
• Downside of Node.js

45. NODE.JS ADVANTAGES
• Server side Javascript
• Javascript is dynamic
• Event based
• Learning curve is less
• Suited for event driven programming
• Uses V8 which relatively faster
• Uses CommonJS module spec

46. NODE.JS ADVANTAGES
Is the server side
JavaScript
programming new?

47. SERVER SIDE JS FRAMEWORKS
• Helma - Rhino
• AppJet - Rhino
• Aptana Jaxer - SpiderMonkey
• CouchDB - SpiderMonkey

48. NODE.JS ADVANTAGES
Is the
Event Driven
programming new?

49. EVENT DRIVEN PROGRAMMING LANGUAGES
• E Programming language
• Event Driven MVC Framework for SmallTalk
• AmbientTalk

50. Similar Frameworks
• Event Machine for Ruby
• Libevent for C
• Twisted for Python

51. Conclusion
So why is Node.js so
popular?

52. Conclusion
I think its because
Ryan Dhal put cool
things together!!!

53. AGENDA
• About Node.js
• Programming in Node.js
• Web Frameworks
• Node.js Internals
• Popularity of Node.js
• Downside of Node.js

54. NODE.JS COMPLAINTS
• Programmers are used to synchronous code
• Exceptions are hard to handle
• Difficult to debug
• Most importantly it is not matured yet
• Doesn’t utilize multi-core CPU

55. Conclusion
FUTURE OF
NODE.JS
???