The document summarizes changes in Rails 3 including: 1. Bundler is introduced for managing gem dependencies through a Gemfile. 2. The ActiveRecord query interface is updated with method chaining and relations to unify finders, named scopes, and with_scope. 3. The ActiveRecord validation API is updated to use hashes instead of separate validator methods for validation options. 4. Views are updated with automatic XSS escaping, unobtrusive JavaScript, and consistent <%= %> usage for output. 5. Internationalization is updated with %{} instead of {{ }} for translations.

1. Rails3 changesets
ihower@gmail.com
2010/8/17

2. About Me
• a.k.a. ihower
• http://ihower.tw
• http://twitter.com/ihower
• Rails Developer since 2006
• The Organizer of Ruby Taiwan Community
• http://ruby.tw
• http://rubyconf.tw

3. Agenda
• Bundler
• ActiveRecord: New Query API
• ActiveRecord: New Validation API
• Views: XSS, Block Helper and JavaScript
• I18n
• New Routing API
• New ActionMailer
• Metal

4. 1. Bundler
http://ihower.tw/blog/archives/4464

5. Gemfile
#
gem "rails", "3.0.0.rc"
# require :require
gem "sqlite3-ruby", :require => "sqlite3"
# Git branch, tag ref
gem 'authlogic', :git => 'git://github.com/odorcicd/authlogic.git',
:branch => 'rails3'
#
gem "rails", :path => '/Users/ihower/github/rails'
# Group
group :test do
gem "rspec-rails", ">= 2.0.0.beta.8"
gem "webrat"
end

6. 2. AR Query API

7. AR queries (1)
method chaining
# Rails 2
users = User.find(:all, :conditions => { :name =>
'ihower' }, :limit => 10, :order => 'age')
# Rails 3
users = User.where(:name => 'ihower').limit(20).order('age')

8. AR queries (2)
Unify finders, named_scope, with_scope to Relation
# Rails 2
users = User
users = users.some_named_scope if params[:some]
sort = params[:sort] || "id"
conditions = {}
if params[:name]
conditions = User.merge_conditions( conditions, { :name => params[:name] } )
end
if params[:age]
conditions = User.merge_conditions( conditions, { :age => params[:age] } )
end
find_conditions = { :conditions => conditions, :order => "#{sort} #{dir}" }
sort = params[:sort] || "id"
users = users.find(:all, :conditions => conditions, :order => sort )

9. AR queries (2)
Unify finders, named_scope, with_scope to Relation
# Rails 3
users = User
users = users.some_scope if params[:some]
users = users.where( :name => params[:name] ) if params[:name]
users = users.where( :age => params[:age] ) if params[:age]
users = users.order( params[:sort] || "id" )

10. AR queries (3)
Using class methods instead of scopes when you need lambda
# Rails 3
class Product < ActiveRecord::Base
scope :discontinued, where(:discontinued => true)
scope :cheaper_than, lambda { |price| where("price < ?", price) }
end
# Rails 3, prefer this way more
class Product < ActiveRecord::Base
scope :discontinued, where(:discontinued => true)
def self.cheaper_than(price)
where("price < ?", price)
end
end

11. 3. AR Validation API

12. AR validation (1)
# Rails 2
class User < ActiveRecord::Base
validates_presence_of :email
validates_uniqueness_of :email
validates_format_of :email, :with => /^[wd]+$/ :on => :create, :message =>
"is invalid"
end
# Rails 3
class User < ActiveRecord::Base
validates :email,
:presence => true,
:uniqueness => true,
:format => { :with => /^([^@s]+)@((?:[-a-z0-9]+.)+[a-z]{2,})$/i }
end
http://asciicasts.com/episodes/211-validations-in-rails-3

13. AR validation (2)
custom validator
# Rails 3
class User < ActiveRecord::Base
validates :email, :presence => true,
:uniqueness => true,
:email_format => true
end
class EmailFormatValidator < ActiveModel::EachValidator
def validate_each(object, attribute, value)
unless value =~ /^([^@s]+)@((?:[-a-z0-9]+.)+[a-z]{2,})$/i
object.errors[attribute] << (options[:message] || "is not formatted
properly")
end
end
end

14. 4.Views

15. Secure XSS
Rails3 will automatically escape any string that does not
originate from inside of Rails itself
# Rails2
<%=h @person.title %>
# Rails3
<%=@person.title %>
# unescape string
<%= @person.title.html_safe %>
<%= raw @person.title %>

16. Unobtrusive JavaScript
# Rails 2
link_to_remote "Name", url_path
# Rails 3
link_to "Name", url_path, :remote => true
# Rails 2
remote_form_for @article do
end
# Rails 3
form_for @article, :remote => true do
end

17. You can change rails.js
to jQuery version
http://ihower.tw/blog/archives/3917

18. consistent <%= %>
# Rails 2
<% form_for @article do %>
end
<% content_for :sidebar do %>
<% end %>
# Rails 3
<%= form_for @article do %>
end
<%= content_for :sidebar do %>
<% end %>

19. consistent <%= %> (2)
# Rails2
<% my_helper do %>
blah
<% end %>
# Rails2 Helper
def my_helper
concat("header")
yield
concat("footer")
end
# or
def my_helper(&block)
tmp = with_output_buffer(&block)
concat("header #{tmp} footer")
end

20. consistent <%= %> (3)
# Rails3
<%= my_helper do %>
blah
<% end %>
# Rails3 Helper
def my_helper(&block)
tmp = with_output_buffer(&block)
"header #{tmp} footer"
end

21. 5. I18n

22. {{ }} becomes to %{}

23. 6. Routing API

24. Routes
nice DSL
# Rails 2
map.resources :people, :member => { :dashboard => :get,
:resend => :post,
:upload => :put } do |people|
people.resource :avatra
end
# Rails 3
resources :people do
resource :avatar
member do
get :dashboard
post :resend
put :upload
end
end

25. 7. ActionMailer

26. ActionMailer
# Rails 2
class UserMailer < ActionMailer::Base
def signup(user)
recipients user.email
from 'ihower@gmail.com'
body :name => user.name
subject "Signup"
end
end
UserMailer.deliver_registration_confirmation(@user)

27. ActionMailer
# Rails 3
class UserMailer < ActionMailer::Base
default :from => "ihower@gmail.com"
def signup(user)
@name = user.name
mail(:to => user.email, :subject => "Signup" )
end
end
UserMailer.registration_confirmation(@user).deliver

28. 8. Metal

29. Removing Metal
• Use Rack middleware
• Use Rack endpoint in the router
• you can inherit ActionController::Metal
to gain controller’s feature

30. Yehuda’s benchmark
rps
2900 Rack
2200 config.middleware.use YourMiddleware
2000 Rails Route
1900 ActionController::Metal
1070 ActionController::Base
825 ActionController::Base render :text
765 ActionController::Base render :template
375 ActionController::Base Template Layout

31. Thanks.
More on http://ihower.tw/blog/archives/4590
and
http://ihower.tw/rails3/