Rails 3 from A to Z

Rails 3 from A to Z

Matt Yoho
@mattyoho

Tuesday, February 8, 2011

RAILS 3 FROM A TO Z MATT YOHO

@speaker = {
:name => ‘Matt Yoho’,
:company => EdgeCase,
:writes => [‘Ruby on Rails’],
:loves => [‘Comic Books’]
}



Goals


Rails is a Domain
Speciﬁc Language
for web applications
written in and on
top of Ruby.



Rails 1.0
December 2005



Rails 2.0
December 2007



Rails 2.3
March 2009



Rails 3.0
August 2010



Rails 3.0.3
November 2010



Agenda



1) Rails Overview



2) Highlight new
features



3) Example app



Rails concepts



MVC


Model
VC


MView
C


MV
Controller


Model class Movie < ActiveRecord::Base

has_many :nights
belongs_to :genre

validates :title,
:presence => true
validates :imdb_id,
:presence => true,
:uniqueness => true

before_save :parse_posters

def poster_url(size = :thumb)
self.posters.find do |p|
p =~ /#{size}.(jpg|png)Z/i
end
end
end



View <div class=”movie”>
<img
src=”<%= @movie.poster_url %>”
alt=”<%= @movie.title %>” />

<h3><%= @movie.title %></h3>
<%= link_to(“See this movie”,
movies_path(@movie))
%>
</div>



Layouts
View
Templates

Partials

Partials



Layouts
View



View
Templates



View

Partials

Partials



Controller class MoviesController <
ApplicationController

before_filter :user_of_age?

def show
id = params[:id]
@movie = Movie.find(id)
render ‘movies/show’
end

private
def user_of_age?
unless current_user.age >= 17
redirect_to(root_path)
end
end

end



Helpers module MoviesHelper

def movie_name(night)
if night.movie.present?
night.movie_title
else
"DUNNO YET"
end
end

end



Routes Movies::Application.routes.draw do

resources :movies do
resources :votes,
:only => [:create,
:destroy]
end

end



Mailer class Notifier <
ActionMailer::Base

default :from =>
"invites@movienight.com",
:subject =>
"You are invited!"

def invited(invitation)
headers[:content_type] =
'text/html'
@night = invitation.night
@invitee = invitation.invitee
mail :to => invitation.email
end

end



DRY


Don’t Repeat
Yourself



Migrations
class CreateMovies < ActiveRecord::Migration
def self.up
create_table :movies do |t|
t.string :title
t.string :imdb_id
t.datetime :release
t.text :posters

t.timestamps
end
end

def self.down
drop_table :movies
end
end



Model
class Movie < ActiveRecord::Base

validates :title,
:presence => true
validates :imdb_id,
:presence => true,
:uniqueness => true

before_save :parse_posters

def poster_url(size = :thumb)
self.posters.find do |p|
p =~ /#{size}.(jpg|png)Z/i
end
end
end



Convention

Conﬁguration



REST


Deﬁne APIs



Resources



Identiﬁed by
URIs



http://movienight.com/movies/123



http://movienight.com/movies/123

Movie

id = 123
...



May be nested



http://movienight.com/movies/123/actors/4



http://movienight.com/movies/123/actors/4

Movie
id = 123

Actor
id = 4


May have
multiple
representations



http://movienight.com/movies/123.json




{"movie" : {"alt_title" : "Batman
Begins", "created_at" :
"2011-01-07T15:51:50Z", "id" :33,
"imdb_id" : "tt0096251", "popularity" :
2.0, "posters" : ["http://
images.themoviedb.org/posters/1113/
poster2rz_thumb.jpg "], "release" :
"2005-06-17T00:00:00Z", "title" : "Batman
Begins", "tmdb_id" : "18393",
"updated_at" : "2011-01-07T15:51:50Z"}}

{JSON}



http://movienight.com/movies/123.xml



http://movienight.com/movies/123.xml

<?xml version="1.0" encoding="UTF-8"?>
<movie>
<title>Batman Begins</title>
<created-at type="datetime">
2011-01-06T22:18:44Z
</created-at>
<id type="integer">13</id>
<imdb-id>tt0372784</imdb-id>
<release type="datetime">
2005-06-17T00:00:00Z
</release>
<tmdb-id>272</tmdb-id>
</movie>

<xml>


Rely on HTTP content
type negotiation



HTTP headers



Request header
Accept: application/json, text/
javascript, */*;



Response header
Content-Type: application/json;



CRUD
via
HTTP VERBS


GET POST
PUT DELETE
HTTP verbs



READ CREATE
UPDATE DELETE
CRUD operations



SHOW CREATE
UPDATE DESTROY
Rails controller actions



SHOW CREATE
UPDATE DESTROY
NEW EDIT INDEX



GET /movies/123 HTTP/1.1
Accept:text/html



CRUD op

Accept:text/html



Resource

Accept:text/html



MoviesController#show

Accept:text/html



Strongly
encouraged by
Rails



Request ->
Response Cycle



Feature details



Commands



rails new ~/app/name



rails new ~/app/name -T -J



-T = Skip Test::Unit



-J = Skip Prototype



rails generate <thing>



rails server



rails console



Dependency
Management



can't activate cucumber (= 0.4.4, runtime)
for [], already activated cucumber-0.6.1
for [] (Gem::LoadError)



$ gem install rails -v2.3.10
Successfully installed activesupport-2.3.9
Successfully installed activerecord-2.3.9
Successfully installed actionpack-2.3.9
Successfully installed actionmailer-2.3.9
Successfully installed activeresource-2.3.9
Successfully installed rails-2.3.9
6 gems installed

2.3


$ gem install rails -v3.0.3
Successfully installed activesupport-3.0.3
Successfully installed builder-2.1.2
Successfully installed i18n-0.5.0
Successfully installed activemodel-3.0.3
Successfully installed rack-1.2.1
Successfully installed rack-test-0.5.7
Successfully installed rack-mount-0.6.13
Successfully installed tzinfo-0.3.23
Successfully installed abstract-1.0.0
Successfully installed erubis-2.6.6
Successfully installed actionpack-3.0.3
Successfully installed arel-2.0.6
Successfully installed activerecord-3.0.3
Successfully installed activeresource-3.0.3
Successfully installed mime-types-1.16
Successfully installed polyglot-0.3.1
Successfully installed treetop-1.4.9
Successfully installed mail-2.2.13
Successfully installed actionmailer-3.0.3
Successfully installed thor-0.14.6
Successfully installed railties-3.0.3
Successfully installed bundler-1.0.7
Successfully installed rails-3.0.3

3.0
23 gems installed



Gemﬁle



source 'http://rubygems.org'

gem 'rails', '~> 3.0.3'
gem 'basic_assumption', '~> 0.4.1'
gem 'devise', '~> 1.1.5'
gem 'dynamic_form', '~> 1.1.3'
gem 'haml', '~> 3.0.24'
gem 'nokogiri', '~> 1.4.4'
gem 'pg', '~> 0.9.0'

gem 'ruby-debug', '~> 0.10.3',
:platforms => :mri_18
gem 'ruby-debug19', '~> 0.11.6',

group :test do
gem 'rspec-rails', '~> 2.4.1'
gem 'factory_girl_rails', '~> 1.0.0'
gem 'fakeweb', '~> 1.3.0'
end


source 'http://rubygems.org'



gem 'rails', '~> 3.0.3'



Name

gem 'rails', '~> 3.0.3'



gem 'rails', '~> 3.0.3'

Version


Platforms
:mri
:mri_18
:mri_19
:mswin
:jruby


gem 'ruby-debug',



gem 'ruby-debug19',



Install from Git



gem 'basic_assumption',
:git => 'git://github.com/mattyoho/basic_assumption.git',
:branch => 'experimental'



GitHub repo





Git repo branch



bundle install



group :test do
gem 'rspec-rails'
gem 'cucumber'
gem 'fakeweb'
end



bundle install --without test



bundle open <gem name>



bundle update



bundle package



http://gembundler.org/

http://gembundler.com/man/gemﬁle.5.html



Models



The great split



ActiveRecord



ActiveRecord

ActiveModel ActiveRelation



ActiveModel



ActiveModel::Validations
ActiveModel::Callbacks
ActiveModel::Errors
ActiveModel::Dirty



validates :title,
:presence => true
:format => /[a-zA-Z]/



ActiveModel::Lint



Mongoid
Datamapper



ActiveRelation



Not as speedy?



@tenderlove

Comeplete rewrite of Arel



Movie.
select(‘*’)
where(“title ILIKE %batman%”).
order(‘release DESC’)



criteria = Movie.
select(‘*’)



criteria = Movie.
select(‘*’)

criteria.to_sql



"SELECT * FROM "movies" WHERE
(title ILIKE '%batman%') ORDER
BY title"



select()
where()
order()
joins()
includes()
limit()
group()
having()
etc.



named_scope



scope



scope :batman_flicks,
where(“title ILIKE %batman%”)



default_scope order(“title”)



Controllers



ActionController

respond_to



ActionController

class MoviesController < ApplicationController

def show
@movie = Movie.find(params[:id])
respond_to do |format|
format.json { render :json => @movie.to_json }
format.xml { render :json => @movie.to_xml }
format.html { render ‘movies/show’ }
end
end

end



ActionController

respond_with



ActionController

class MoviesController < ApplicationController

respond_to :json, :xml, :html

def show
@movie = Movie.find(params[:id])
respond_with(@movie, :status => :ok)
end

end



ActionMailer
class Mailer < ActionMailer::Base

default :from => "invites@movienightapp.com",
:subject => "You’ve been invited to a movie night!"

def invitation(invitation)
headers[:content_type] = 'text/html'
@night, @invitee = invitation.night, invitation.invitee
end

end



ActionMailer
class Mailer < ActionMailer::Base

default :from => "invites@movienightapp.com",
:subject => "You’ve been invited to a movie night!"

def invitation(invitation)
headers[:content_type] = 'text/html'
@night, @invitee = invitation.night, invitation.invitee
end

end

message = Mailer.invitation(@invitation)
message.deliver



mail gem



ActionMailer::Base

AbstractController::Base

ActionController::Base



Views



Whitelist, not blacklist



<%= h(@movie.description) %>



<%= @movie.description %>



<%= raw(“<h2>#{@movie.title}</h2>”) %>



<%= raw(“<h2>#{@movie.title}</h2>”) %>

String#html_safe



Unobtrusive JS



link_to_remote "Destroy",
:url => movie_url(@movie),
:method => :delete



link_to_remote "Destroy",
:url => movie_url(@movie),
:method => :delete

<a href="#" onclick="new Ajax.Request('/movies/4',
{asynchronous:true, evalScripts:true, method:'delete'});
return false;">Destroy</a>



link_to "Destroy", movie_url(@movie),
:remote => true,
:method => :delete



link_to "Destroy", movie_url(@movie),
:remote => true,
:method => :delete

<a href="/movies/4" data-remote=”true" data-method=”delete”>Destroy</a>



https://github.com/rails/jquery-ujs



Routing



Pneumatic tubes,
popular in the late
19th and early 20th
century for
transporting messages,
cash, etc.



Resources

Text



CoffeeShop::Application.routes.draw do

resources :cups do
resources :shots
end

resources :coffee_beans

end



cup_shots GET /cups/:cup_id/shots(.:format) {:action=>"index", :controller=>"shots"}
POST /cups/:cup_id/shots(.:format) {:action=>"create", :controller=>"shots"}
new_cup_shot GET /cups/:cup_id/shots/new(.:format) {:action=>"new", :controller=>"shots"}
edit_cup_shot GET /cups/:cup_id/shots/:id/edit(.:format) {:action=>"edit", :controller=>"shots"}
cup_shot GET /cups/:cup_id/shots/:id(.:format) {:action=>"show", :controller=>"shots"}
PUT /cups/:cup_id/shots/:id(.:format) {:action=>"update", :controller=>"shots"}
DELETE /cups/:cup_id/shots/:id(.:format) {:action=>"destroy", :controller=>"shots"}
cups GET /cups(.:format) {:action=>"index", :controller=>"cups"}
POST /cups(.:format) {:action=>"create", :controller=>"cups"}
new_cup GET /cups/new(.:format) {:action=>"new", :controller=>"cups"}
edit_cup GET /cups/:id/edit(.:format) {:action=>"edit", :controller=>"cups"}
cup GET /cups/:id(.:format) {:action=>"show", :controller=>"cups"}
PUT /cups/:id(.:format) {:action=>"update", :controller=>"cups"}
DELETE /cups/:id(.:format) {:action=>"destroy", :controller=>"cups"}
coffee_beans GET /coffee_beans(.:format) {:action=>"index", :controller=>"coffee_beans"}
POST /coffee_beans(.:format) {:action=>"create", :controller=>"coffee_beans"}
new_coffee_bean GET /coffee_beans/new(.:format) {:action=>"new", :controller=>"coffee_beans"}
edit_coffee_bean GET /coffee_beans/:id/edit(.:format) {:action=>"edit", :controller=>"coffee_beans"}
coffee_bean GET /coffee_beans/:id(.:format) {:action=>"show", :controller=>"coffee_beans"}
PUT /coffee_beans/:id(.:format) {:action=>"update", :controller=>"coffee_beans"}
DELETE /coffee_beans/:id(.:format) {:action=>"destroy", :controller=>"coffee_beans"}



cups GET /cups(.:format) {:action=>"index"}
POST /cups(.:format) {:action=>"create}
new_cup GET /cups/new(.:format) {:action=>"new"}
edit_cup GET /cups/:id/edit(.:format) {:action=>"edit"}
cup GET /cups/:id(.:format) {:action=>"show"}
PUT /cups/:id(.:format) {:action=>"update"}
DELETE /cups/:id(.:format) {:action=>"destroy}

:controller=>"cups"




resources :cups do
resources :shots
end

resources :coffee_beans, :except => :destroy

end




resources :cups do
resources :shots
end

resources :coffee_beans,
:only => [:new, :show]

end




resources :cups do
resources :shots
end

resources :coffee_beans,
:path_names => [:edit => ‘brew’]

end




resources :cups do
resources :shots
end

resources :coffee_beans
resource :shop, :except => [:destroy]

end


RAILS3 ROUTES MATT YOHO

Singular
Routes



Simple routes

Movienight::Application.routes.draw do

match "/search", :to => "movies#search"

end



Named routes


match "/search", :to => "movies#search",
:as => "title_search"

end



Method-constrained routes


match "/search", :to => "movies#show",
:via => :get

end



Method-constrained routes


get "/search", :to => "movies#search",
:via => :get

end



Root route


root :to => "nights#index"

end



Non-resourceful
Methods




resources :coffee_beans do
collection do
get :dark_roast
get :light_roast
end

member do
put :chew
end
end

end



Constraints




match "/search", :constraints =>
{:subdomain => "mst3k"}

end




match "/movies/:imdb_id", :constraints =>
{:imdb_id => /d+/}

end




constraints(:subdomain => "mst3k") do
resource :projector do
resources :bmovies
end
end

end



Optional
Segments



# Rails 2
ActionController::Routing::Routes.draw do |map|

map.connect "/:controller/:action/:id"

end

# Rails 3

match "/:controller(/:action(/:id))(.:format)"

end


RAILS 3 FROM A TO Z
Rack MATT YOHO

Endpoints



Rack




match "/hello", :to => Proc.new do |env|
[
200,
{‘Content-Type’ => ‘text/plain’},
[“Hello, world”]
]
end

end




match "/hello", :to => Proc.new do |env|
[
200,
{‘Content-Type’ => ‘text/plain’},
[“Hello, world”]
]
end

end
hello /hello(.:format) {:to=>#<Proc:0x00000100f1da28@/app/conﬁg/routes.rb:7>}



Sinatra



require 'sinatra/base'
class ApiApp < Sinatra::Base

get "/hello" do
whom = request.cookies["whom"]
whom ||= "world"
set_cookie(‘whom’, whom)
"Hello, #{whom}"
end

post "/hello" do
set_cookie(‘whom’, params[:whom])
redirect "/hello"
end
end



scope "/api" do
match "(*path)", :to => ApiApp
end
end



mount




mount ApiApp, :at => "/api"

end



Special
case?





end



MoviesController.action(:search)



end



Example



Movienight



http://railsapi.com



Rails for Zombies
http://railsforzombies.org/



Rails 3 Cheat
Sheets
http://blog.envylabs.com/2010/12/
rails-3-cheat-sheets/



Rails 3 Upgrade
Handbook
http://www.railsupgradehandbook.com/


Thank you!

Matt Yoho
@mattyoho
matt@edgecase.com


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