Ruby on Rails
An Introduction
Mark S. Maglana, CompE, MM

Let's get this out of the way...
» My name is Mark S. Maglana
» Bachelor's Degree in Computer Engineering from
the University of San Carlos, Cebu
» Master in Management from the University of the
Philippines in Mindanao
» Computer geek since grade 5 (BASIC, QBASIC)
» Suffered through C, assembly in college
» Web dude since 1997, started with ASP 1.0
» ASP.Net, PHP (w/ CakePHP)
» UML, VB, .Net, C#, Java, Lotus Notes/Domino

“I constantly remind myself that there are multiple
ways and numerous technologies [for] solving a
single problem, some better than others.”
“By being loyal to one technology stack, I am bound
to unconsciously make biased decisions, which will
ultimately hinder my ability to deliver business
value.”
- Stephen Chu
http://tinyurl.com/zz995

A Programming
Language
Ruby on Rails
A Web Framework
built w/ Ruby

Hold it right there, sparky...

This is an introduction, not a tutorial
We wont get in-depth with Ruby and Rails
(You're too intelligent to be spoon fed)
I assume you're familiar with OOP

Ruby
» Created by Yukihiro “Matz” Matsumoto in 1993
» A language designed for humans, not compilers
» A true Object-Oriented language
» Everything you manipulate in Ruby is an object
» They all ultimately inherit from a class named
Object (Surprise! Surprise!)
» Because everything is an object, there's none of
that primitive types vs. reference types silliness.

Hello World
# The famous Hello World
# program is trivial in
# Ruby. You don't need:
#
# * a \"main\" method
# * newline escapes
# * semicolons
#
# Here's the code:
puts \"Hello World!\"
Ruby won't force you to define a class if you don't
need to. In such a case, Ruby automatically
encloses your statement in an Object instance.

Other Examples
door.close if door.is_open?
5.times { puts “Odelay!” }
my_text = 'restaurant'
exit unless my_text.include? 'rant'
animals = ['cat', 'dog', 'fox']
animals.each {|animal| puts animal.capitalize}
small_number = 1212123
really_big_number = 1412432423429340234581340234
pretty_number = 12_000_000_000

And here's one more...
class Person
attr_accessor :name, :age, :sex
end
person = Person.new
person.name = 'Perting E. Soga'
person.age = 36
person.sex = 'M'
puts person.name # Perting E. Soga
puts person.age # 36
puts person.sex #M

Ruby Conventions
» Variables starting with $ are Global Variables
(ex. $x, $1, $chunky_bacon)
» Variables starting with @ are Instance Variables
(ex. @width, @x, @y)
» Variables starting with @@ are Class Variables
(ex. @@brokeback_coding, @@choo_choo)
» Variables without prefixes are Local Variables
(ex. chicken_noodles, white_flower)
» Constants are always capitalized
(ex. Time, Array, LuckyPenguin)

Rails
» Created by David Heinemeier Hansson in 2003
» A web application framework built using Ruby
» Uses the Model-View-Controller (MVC) design
pattern
» Also uses the ActiveRecord design pattern
» Some ex-Java programmers claim Rails helped
them develop applications 10x faster

de
co
Show me the money!

How Rails Works
/posts/show/1
1.
9. Web Server
Internet
2.
8.
show.rhtml
posts_controller.rb
PostsController::show()
view
7.
controller
6.
post.rb
blog_production
Post::find(1)
5.
3.
model
database
4.

Recommended Set-up
HTTP
mod_proxy
Apache 2.2+
Internet
mod_proxy_balancer
HTTP HTTP HTTP
Mongrel Mongrel Mongrel
database

Additional Reading
» www.ruby-lang.org
» www.rubyonrails.org
» http://pine.fm/LearnToProgram/
» ruby-phil@googlegroups.com
» Google for “OnLAMP Rolling with Rails”
» #rubyonrails and #ruby-lang in IRC (freenode)
» wiki.rubyonrails.org
» api.rubyonrails.org
» Agile Web Development book
» Programming Ruby book

And we're done!