Introduction to rails

Introduction to Ruby on Rails
(aka: Rails for you)
Go Frendi Gunawan

About Me
● Go Frendi Gunawan
● Developer of No-CMS and Kokoropy
● Lecturer at STIKI Malang
● Starting a startup business
● http://gofrendiasgard.github.io

Ruby
● A fully OOP programming language
● Created by Yukihiro Matsumoto (Matz)
● Influenced by Python, Perl, dan Java
● Easy to write
● A bit hard to read
● Easy and fun to learn (http://tryruby.org)
● Has interactive console called “irb”
● Has package control library called “gem”

Ruby – Variable
● Don't need to implicitly write datatype
a = 5
b = “Some string”

Ruby – Block
● You can use “end” keyword, no curly braces as in C or Java:
# branch
if 3>4
puts “She hates me”
else
puts “She loves me”
end
# loop
i = 5
while i>0
puts i
i = i-1
end

Ruby – Function & Function Call
● Define a function:
def add(a,b)
a+b
end
● This will works:
add 4,5
as well as this:
add(4,5)

Ruby – Everything is object
● No primitive datatype like java
● This will yield “Hello world!”:
“!dlrow elloH”.reverse
A string like “!dlrow elloH” has reverse method, you don't even need to
put it in a variable
● This will yield 8:
7.next
● This will blow up your mind:
[1,2,3,4,5].each{|num| puts num+1}
It is like foreach in php. You iterate through the array, put each element
into a local variable called “num” and print num+1 into the screen.

Ruby-Class & Object
● Define a class
class Scientist
def initialize(name)
@name = name
end
def introduce()
puts “My name is ” +@name
end
end
● Define an subclass
class Mad_Scientist < Scientist
end
● Make object
sheldon = Scientist.new(“Sheldon Cooper”)
sheldon.introduce

Rails
● A very good web framework
● Full of “auto-magic” functionality
● Created by David Heinemeier Hansson
● Has several philosophy:
– DRY (Don't Repeat Yourself)
– MVC (Model View Controller)
– Convention ofer Configuration (CoC)
● Powering several big websites:
– Github
– Twitter
– Shopify

Installing Rails
● If you are using linux or Mac, you can follow
installation steps in
http://rubyonrails.org/download/
FYI: you can even use apt-get in ubuntu.
● Windows user simply use this:
http://railsftw.bryanbibat.net/ to save all the pain
of compiling things.

Starting Rails
● Open rails console, type this:
rails new YOUR_APP_NAME
● Rails will generate several files & folders for you. Basically,
you only need to take attention on:
– config
– app/models
– app/controllers
– app/models
● Type rails s and fire your browser to
http://localhost:3000

Scaffolding – Rails's best feature
● Scaffold articles
– Rails g scaffold articles title:string
body:text
● Do “migration” (aka: create your database without
touching it)
– rake db:migrate
● Fire your browser to http://localhost:3000/articles
and it is.

Use bootstrap themes (1)
● Add some gems first. Open
YOUR_APP_NAME/Gemfiles, add this:
– gem 'therubyracer'
– gem 'less-rails'
– gem 'twitter-bootstrap-rails'
● Install the gems
– bundle install

Use bootstrap themes (2)
● install bootstrap
– rails g bootstrap:install
● Override Layout
– rails g bootstrap:layout application
fixed -f
● Override article's theme
– rails g bootstrap:themed articles -f
● See the result

Here is what we made so far
(Pretty cool for something we didn't even code...)

Tips and Tricks
● If you want to change the view manually, just go
to app/views folder
● If you want articles to be your homepage, then
you can modify config/routes.rb and add
this:
– root :to => "articles#index"

Further reading
● http://tryruby.org/
● http://railsforzombies.org/
● http://guides.rubyonrails.org/getting_started.html

Conclusion
● You have see how Ruby-on-Rails can help you
develop application (or at least prototype)
easily.
● Rails is a great framework, it is very simple to
make a working CRUD application. However,
deeper understanding about the language and
the framework is required if you want to build a
serious application

Introduction to rails

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