Introduction to Ruby and Ruby on Rails. Harmful for PHP developers

1. In Ruby 's arms by Tom Waits
The sexy programming language that will
change you career as a developer
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2. Look mam, PHP!
I can makez
webzitez
There are people who actually like programming.
I don't understand why they like programming.
- Rasmus Lerdorf (creator of php)
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3. Who am I?
xPHP-er who learned
Ruby and matured
Founder at Sfalma.com
Partner at NiobiumLabs
http://6pna.com
@panosjee

4. What is special about Ruby?
Open Source
Simple (before you dive in the deep)
Elegant
Dynamic
Made for programmers' productivity and sanity
Modern
Has a vibrant community
Huge amount of libraries and framework
Great VMs (take a look at JRuby)
Not meant to be server-side only (I look at you php)
Sexy! (how much sexy?)
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5. Even
Berlusconi
took Ruby
for a spin!

6. Let 's start from the basic
Everything is an Object
Functions (methods) are messages
Object communicate with messages
No type casting. Each method should know what is
expecting. Maybe that 's why Rubyists are so Test
Paranoid
Operators are syntactic sugar for methods. You can
redefine them as well.
Blocks and Closures (start thinking functionally and
reach developers' Nirvana)
Mixins
IRB (console)
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7. Open an IRB, load anything, play, explore, learn, debug!

8. Some Syntactic Sugar
# define a hash
hash = {a: 1, b:2, c:3, d:0, e:9, f:4}
# get key, values that are greater than 3
hash.select{ |k,v| v > 3 }
# multiple all values by 2 and store in new array
new_array = hash.values.map { |v| v * 2 }
# You know now about block and closures!
# Get all odd numbers from 1 to 10 multiplied by 10
1.upto(10).map { |i| i*10 if i.odd? }.compact
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9. Some Magic Included
# We want a small DSL* that gives us relevant dates
# to today
# Normally we type
now = Time.now
# => 2011-04-09 19:02:22 +0300
# We add the seconds (of a day) to advance in Time
now + 60 * 60 * 24
# => 2011-04-10 19:02:22 +0300
# Not cool enough, let 's see what we can do
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10. Some Magic Included (II)
# Remember everything is an object that we can
# always overload
class Fixnum
def days
self * 60 * 60 * 24
end
end
# Let 's see what it does
3.days
# => 172800
# the total number of seconds of 3 days
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11. Some Magic Included (III)
# Let 's reopen and add spell some magic
class Fixnum
def from_now
Time.now + self
end
end
# Let 's see what it does
3.days.from_now
# => 2011-04-12 19:10:45 +0300
# Congratulations! You just created your first DSL
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12. What the heck is DSL?
DSL = Domain Specific Language
DSLs allow you to create a mini language that
solved specific problem. So instead of expressing
everything in a language made for computers you
can create a language that solves problem *BUT*
humans can understand them too.
The DSL concept was introduced by Lisp. Since
Lisp is only for the enlightened ones you can use
Ruby *TODAY* to create your DSLs.
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13. A wealth of libraries
Installing a library in Ruby is as easier than
getting off your bed:
gem install rails
Ruby libraries are distributed as gems. You can
find some millions at http://www.rubygems.org
and of course study the code (usually at Github).
Gem commands resemble apt-get of Debian
Sometimes though libraries have a tendency to
create nightmares due to dependencies. Bundler
helps you sleep tight
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14. Hey I want to learn Rails!
Hold your horses pow! Rails is a great tools
but your Rails app will look like PHP if you
do not learn and master Ruby, the language.
Most Rails noobs that come from PHP
continue the PHP attrocities thus creating
terrible spaggheti code.
Rails will not make you write excellent apps.
Learning, persistence and coding will. So we
have to master Ruby, the language.
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15. Let 's dive into the Web (Rack)
Have you heard of CGI, FastCGI? You know the old way a
server (Apache) could talk to a script?
Well in Ruby we have Rack. Rack provides a minimal
interface between webservers supporting Ruby and Ruby
frameworks.
Whatever programs sits between our Ruby application and
the server we call it middleware.
Rack enables you to talk HTTP.
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16. Let 's dive into the Web (Rack)
You can even expose any Ruby object as a Web Service!
BEWARE: Try only at home!
require 'rubygems'
require 'rack'
class Object
def webapp
class << self
define_method :call do |env|
func, *attrs = env['PATH_INFO'].split('/').reject(&:empty?)
[200, {}, send(func, *attrs)]
end
end
self
end
end
Rack::Handler::Mongrel.run [].webapp, :Port => 8080
# http://localhost:8080/push/1 -> 1
# http://localhost:8080/to_a -> 1
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17. * it does not make you a Rock Star
hard work, love and code'n' roll does

18. You speak HTTP, now sing HTML
Rails is collection of Ruby libraries that sit on top of Rack
and allow you to create well organized web applications.
Rails started by DHH at 37signals around 2004. At the
beginning it was a very opinionated framework and caused
a tsunami in the web development world. Nowadays most
web frameworks are based on the Rails philosophy.
Rails favors convention over configuration so you should
things the Rails way and stop writing XML files (hey Java-
ers) or spaghetti code (hello PHPers)
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19. Why do people use Rails?
Rails is magnificent tools for creating Web Applications. If
your main focus is Content Websites of course you can do
great stuff with Rails but you can stick to Drupal.
Some famous Ruby on Rails Web (sites/apps) are:
Twitter - http://twitter.com
Groupon - http://www.groupon.com
Soundcloud - http://www.soundcloud.com
Github - http://www.github.com
Basecamp - http://www.basecamphq.com
Slideshare - http://www.slideshare.com
Skroutz.gr - http://www.skroutz.gr
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21. Everything at its place
Rails is an MVC framework. MVC stands for:
Model, an ORM, a class that talks and abstracts your
database. We also add logic here. So for example the
model Person will contain the logic. ex. person.
write_me_code, person.pay_your_bills
Controllers, controller will orchestrate your app. They
take a user 's request spin up some models (if needed)
collect the results and pass the to the views
View, the view can be an HTML file, JSON, XML,
PDF, a mobile friendly HTML page. You name it!
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22. Stay RESTful!
Rails + REST = L.F.E.
REST stands for Representional State Transfer.
Rails wants you to think in terms of objects.
Your URLs are not pointer to some stupid files:
ex. /edit_category.php?c_id=2
Rails uses all HTTP verbs GET, POST, DELETE, PUT,
HEAD and matches them to a URL. For example.
GET /category/1 # show category info
POST /category # creates a category
PUT /category/1 # updates a category
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23. 1. The user hits the server
that talks to Rack. Rack
calls the Routes.
2. The Routes will match
the URL that user asked
and dispatch the request
data to the Controller.
3. The Controller gets the
request data and calls
the Models (database) if
need.
4. The model returns data
5. The Controller collects
the data from the model
and spits them to the
View.
6. The View returns the
formatted data (HTML,
JSON etc) to the
Controller.
7. The Controller talks to
the Server and gives
http://gmoeck.github.com/2011/03/10/sproutcore-mvc-vs-rails-mvc.html
him the web page.

24. Use the command line
It is easier than what you think. I guess you can understand
the following:
rails new awesome_app
rails generate model Person name:string money:integer
rails generate controller Main index about contact
rails generate scaffold Category name:string
Rails uses migrations to create your database schema. No
more manual changes. If you work in a team there is not
other way to go!
rake db:migrate
rake db:migrate:reset
rake db:seed
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25. Routes (URLs) to functions not files!
A url is routes to code a function inside a controller. You
can change it a breeze and create meaningful urls:
Guitar121::Application.routes.draw do
match "/account" => "users#edit", :as => 'account'
resources :attachments
get "courses/missing", :as => :missing_course
resources :courses do
resources :attachments
member do
get :invite
put :uninvite
end
end
end
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26. Bye bye SQL, we won't miss ya!
ActiveRecord (the Model) will abstract the database from
us. You can switch your app from SQLite to Oracle and do
not change any query (hopefully).:
# Get the first user with specific id and rank > 0
User.where(:id=>params[:id], :rank > 10).first
# Get all videos in category 3 order by views
Video.where(:category_id=>3).order("views").all
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27. Get your hands dirty now!
Probably there are too many new notions and words you
cannot understand the only way to go is get down to write
some code. The Ruby community is very enthousiastic and
active. So head your browser to the following links and
dive into Ruby and Rails:
http://www.ruby-lang.org/en/
http://railscasts.com/
http://railsforzombies.org/
http://ruby5.envylabs.com/
http://rubyst.es
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28. Thank you!
@panosjee - http://6pna.com
Ruby and Rails are not silver bullets but they can open a window to
better productivity, developer happiness and cool hacks. Use at your
own risk!
You may also learn Python or Node.js just stop using
PHP! Special thanx to @Drakevr for fixing my typos!
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