Upgrading to Rails 3

Upgrading to
Rails 3
OSCON 2010
Thursday, July 22, 2010

Michael Bleigh
@mbleigh

OSCON 2010

Jeremy McAnally’s
Rails Upgrade Handbook
bit.ly/railsupgrade
OSCON 2010

Rails 3 is
Diﬀerent
OSCON 2010

Rails 3 is a
Bi ange
OSCON 2010

Why the hell
should I bother?

OSCON 2010

Modularity

OSCON 2010

Rails 2.3 Stack
ActiveRecord

ActiveSupport

ActiveResource

ActionPack

Test::Unit

OSCON 2010

Rails 3 Ecosystem
DataMapper
ActiveRecord MongoMapper

ActiveSupport

ActiveResource ActiveModel

ActionPack

RSpec Bacon
Test::Unit

OSCON 2010

Rails 2.3 Controller

ActionController::Base

ApplicationController

YourController

OSCON 2010

Rails 3 Controller
AbstractController::Base

ActionController::Metal

ActionController::Base

ApplicationController

YourController

OSCON 2010

Less Monkeypatching

OSCON 2010

Security
darwinbell via Flickr

OSCON 2010

small change,
big impact

OSCON 2010

HTML is escaped
by default.

OSCON 2010

<div class='comment'>
<%= comment.body %>
</div>


<div class="comment">
<%= comment.body.html_safe %>
</div>


<div class="comment">
<%=raw comment.body %>
</div>

It’s a good thing.TM

OSCON 2010

New Apis

OSCON 2010

e Router

OSCON 2010

Rack Everywhere!

OSCON 2010

Fancy New DSL

OSCON 2010

More Powerful

OSCON 2010

# Rails 2.3
map.connect '/help', :controller => 'pages',
:action => 'help'

# Rails 3
match '/help', :to => 'pages#help'

# Rails 2.3
map.resources :users do |users|
users.resources :comments
end

# Rails 3
resources :users do
resources :comments
end


# Rails 2.3
with_options :path_prefix => 'admin',
:name_prefix => 'admin' do |admin|
admin.resources :users
admin.resources :posts
end

# Rails 3
namespace :admin
resources :users
resources :posts
end


# Rails 3

constraints(:subdomain => 'api') do
resources :statuses
resources :friends
end

match '/hello', :to => lambda{ |env|
[200, {'Content-Type' => 'text/plain'}, 'Hello
World']
}

match '/other-site', :to => redirect('http://url.com')


A ionMailer

OSCON 2010

It’s (mostly) just
a controller.

OSCON 2010

class Notifier < ActionMailer::Base
default :from => "mikel@example.org"

def welcome_email(user)
@name = user.name
attachments['terms.pdf'] = File.read(
Rails.root.join('docs/terms.pdf')
)
mail(:to => user.email, :subject => "G’day Mate!")
end
end


class UsersController < ApplicationController
respond_to :html
def create
@user = User.new(params[:user])

Notifier.welcome_email(@user).deliver if @user.save
respond_with @user
end
end


Bundler

OSCON 2010

Caution: Entering
Controversy

OSCON 2010

# Rails 2.3

# environment.rb
config.gem 'acts-as-taggable-on'
config.gem 'ruby-openid', :lib => false

# test.rb
config.gem 'rspec'
config.gem 'cucumber'

# Rails 3

# Gemfile
gem 'acts-as-taggable-on'
gem 'ruby-openid', :require => false

group :test do
gem 'rspec'
gem 'cucumber'
end


Dependency
Resolver

OSCON 2010

A iveRelation

OSCON 2010

Like named scopes,
only more so.

OSCON 2010

# Rails 2.3

Book.all(
:conditions => {:author => "Chuck Palahniuk"},
:order => "published_at DESC",
:limit => 10
)

# Rails 3

Book.where(:author => "Chuck Palahniuk")
.order("published_at DESC").limit(10)


Inherently
Chainable


# Rails 3

def index
@books = Book.where(:author => params[:author])
if params[:author]
@books = @books.order(:title) if params[:sort] ==
'title'
respond_with @books
end


# Rails 2.3

class Book
named_scope :written_by {|a| {:conditions => {:author => a}}}
named_scope :after {|d| {:conditions => ["published_on > ?", d]}}
# Rails 3

class Book
class << self
def written_by(name)
where(:author => name)
end

def after(date)
where(["published_on > ?", date])
end
end
end


Be er H ks

OSCON 2010

Generators

OSCON 2010

config.generators do |g|
g.orm :mongomapper
g.test_framework :rspec
g.integration_tool :rspec
end

rails g model my_model


Engines

OSCON 2010

#lib/your_plugin/engine.rb
require "your_plugin"
require "rails"

module YourPlugin
class Engine < Rails::Engine
engine_name :your_plugin
end
end


Lots more...
railsdispatch.com
edgeguides.rubyonrails.org

OSCON 2010

But we’re already
on Rails 2.3!

OSCON 2010

How do we cope?

OSCON 2010

Ignore it all
and cheat.
github.com/rails/
rails_upgrade

OSCON 2010

Finds Key
Blockers:
Routes, Bundler,
application.rb

OSCON 2010

3 Step Process

OSCON 2010

Analyze Your App
rake rails:upgrade:check

OSCON 2010

Backup 2.3 Files
rake rails:upgrade:backup

OSCON 2010

Run Upgrades
rake rails:upgrade:routes
rake rails:upgrade:gems
rake rails:upgrade:configuration

OSCON 2010

Takeaways

OSCON 2010

Tests help.
Unfortunately, they
may not run.


Don’t be afraid to
re-generate.


Just take it one
problem at a time.


eﬆions?
@mbleigh @intridea
github.com/mbleigh/upgrade-to-rails3

OSCON 2010

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