What's New in Rails 4

I give a run-down of some of the latest features in Rails slated for the 4.0 release, and tips on how to prepare your Rails 3 app for upcoming changes.

Transcript

1. WHAT’S NEW IN
   RAILS 4
   Ben Hughes
   @rubiety
   http://benhugh.es
   Thursday, February 7, 13
   

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2. RAILS EVOLUTION
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3. RAILS 2:
   REST ARCHITECTURE
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4. RAILS 3:
   MODULARIZATION
   ASSET PIPELINE
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5. RAILS 4:
   CLOSET-CLEANING
   FORWARD REFINEMENT
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7. RUBY 1.9.3 REQUIRED
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8. STRONG PARAMETERS
   class PeopleController < ApplicationController
   def create
   @person = Person.create(params[:person])
   end
   end
   class Person < ActiveRecord::Base
   attr_accessible :name, :age
   end
   In Rails 3:
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9. STRONG PARAMETERS
   class PeopleController < ApplicationController
   def create
   @person = Person.create(person_params)
   end
   private
   def person_params
   params.require(:person).permit(:name, :age)
   end
   end
   Use in Rails 3 Today:
   https://github.com/rails/strong_parameters
   In Rails 4:
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10. THREAD SAFE BY DEFAULT
    Make sure your code & all gems is thread safe!
    Or disable thread safety (middleware Rack::Lock).
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11. LIVE STREAMING
    class MyController < ActionController::Base
    include ActionController::Live
    def stream
    response.headers['Content-Type'] = 'text/event-stream'
    100.times {
    response.stream.write "hello world\n"
    sleep 1
    }
    response.stream.close
    end
    end
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12. LIVE STREAMING CAVEATS
    • Actions run in separate thread; controller action code must be
    thread save!
    • Concurrent Ruby Server Required (puma, rainbows!, thin)
    • Headers must be written before anything else
    • Streams must be closed
    http://tenderlovemaking.com/2012/07/30/is-it-live.html
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13. TURBOLINKS
    https://github.com/rails/turbolinks
    http://railscasts.com/episodes/390-turbolinks
    Similar to PJAX
    Use in Rails 3 Today:
    gem “turbolinks”
    // app/assets/javascripts/application.js
    //= require jquery
    //= require jquery_ujs
    //= require turbolinks
    //= require_tree .
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14. BEFORE_FILTER
    =>
    BEFORE_ACTION
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15. POSTGRES ARRAY SUPPORT
    class AddTagsToArticles < ActiveRecord::Migration
    def change
    change_table :articles do |t|
    t.string :tags, array: true
    end
    end
    end
    article.tags = ['rails']
    article.save
    # UPDATE "articles" SET "tags" = '{"rails"}'
    # WHERE "articles"."id" = 1
    HStore Support
    New Data Types Support
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16. AREL .WHERE.NOT(:A => 1)
    Article.where.not(title: 'Rails 3')
    Article.where.not(title: ['Rails 3', 'Rails 5'])
    Article.where("title != ?", "Rails 3")
    Article.where("title NOT IN (?)", ["Rails 3", "Rails 5"])
    In Rails 3:
    In Rails 4:
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17. AREL .FIRST / .LAST
    In Rails 3:
    Calling .first or .last was indeterminate (DB-specific).
    In Rails 4:
    Calling .first or .last defaults to using ORDER BY id.
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18. AREL .NONE
    @posts = current_user.visible_posts.where(:name => params[:name])
    def visible_posts
    case role
    if 'Country Manager'
    Post.where(:country => country)
    if 'Reviewer'
    Post.published
    if 'Bad User'
    # returning [] instead breaks the previous code; not chainable
    Post.where("1=0")
    end
    end
    In Rails 3:
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19. AREL .NONE
    @posts = current_user.visible_posts.where(:name => params[:name])
    def visible_posts
    case role
    if 'Country Manager'
    Post.where(:country => country)
    if 'Reviewer'
    Post.published
    if 'Bad User'
    # returning [] instead breaks the previous code; not chainable
    Post.none
    end
    end
    In Rails 4:
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20. AREL BANG! METHODS
    class PeopleController < ApplicationController
    def index
    @people = People.active
    @people = @people.where(:first_name => params[:first_name]) if params[:last_name].present?
    @people = @people.where(:last_name => params[:last_name]) if params[:last_name].present?
    end
    end
    In Rails 3:
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21. AREL BANG! METHODS
    class PeopleController < ApplicationController
    def index
    @people = People.active
    @people.where!(:first_name => params[:first_name]) if params[:last_name].present?
    @people.where!(:last_name => params[:last_name]) if params[:last_name].present?
    end
    end
    In Rails 4:
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22. ROUTING CONCERNS
    Penguin::Application.routes.draw do
    resources :projects do
    resources :comments
    end
    resources :tasks do
    resources :comments
    end
    resources :articles do
    resources :comments
    end
    end
    In Rails 3:
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23. ROUTING CONCERNS
    In Rails 4:
    Penguin::Application.routes.draw do
    concern :commentable do
    resources :comments
    end
    resources :projects, concerns: :commentable
    resources :tasks, concerns: :commentable
    resources :articles, concerns: :commentable
    end
    Use in Rails 3 Today:
    https://github.com/rails/routing_concerns
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24. CACHING GEM
    EXTRACTIONS:
    gem “actionpack-page_caching”
    gem “actionpack-action_caching”
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25. OBSERVERS/SWEEPERS
    EXTRACTED
    gem “rails-observers”
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26. FRAGMENT CACHE DIGESTS
    # app/views/todolists/_todolist.html.erb
    <% cache todolist do %>
    My todolist: <%= todolist.name %>
    <%= render document.comments %>
    <% end %>
    # app/views/comments/_comment.html.erb
    <% cache comment do %>
    My comment: <%= comment.body %>
    <% end %>
    In Rails 3:
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27. FRAGMENT CACHE DIGESTS
    # app/views/todolists/_todolist.html.erb
    <% cache [ "v1", todolist ] do %>
    My todolist: <%= todolist.name %>
    <%= render document.comments %>
    <% end %>
    # app/views/comments/_comment.html.erb
    <% cache [ "v1", comment ] do %>
    My comment: <%= comment.body %>
    <% end %>
    In Rails 3:
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28. FRAGMENT CACHE DIGESTS
    # app/views/todolists/_todolist.html.erb
    <% cache todolist do %>
    My todolist: <%= todolist.name %>
    <%= render document.comments %>
    <% end %>
    # app/views/comments/_comment.html.erb
    <% cache comment do %>
    My comment: <%= comment.body %>
    <% end %>
    In Rails 4:
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29. NO VENDORED PLUGINS
    rm -rf vendor/plugins
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30. AR SESSION STORE
    GEM EXTRACTION
    gem “activerecord-session_store”
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31. ACTIVERESOURCE
    EXTRACTED
    gem “activeresource”
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32. SPROCKET-POWERD
    ASSET PIPELINE EXTRACTED
    gem “sprocket-rails”
    Differential Pre-compilation (Finally!)
    Silent Logging (replaces need for quiet_assets gem)
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33. SCOPES REQUIRE CALLABLES
    In Rails 4:
    class Team < ActiveRecord::Base
    scope :active, where(active: true)
    scope :recent, where(published_at: Time.now - 2.weeks)
    end
    class Team < ActiveRecord::Base
    scope :active, -> { where(active: true) }
    scope :recent, -> { where(published_at: Time.now - 2.weeks) }
    end
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34. DEPRECATED FINDERS
    # find_all_by_
    Rails 3: Team.find_all_by_name('Justice League')
    Rails 4: Team.where(name: 'Justice League')
    # find_last_by_
    Rails 3: Team.find_last_by_name('Justice League')
    Rails 4: Team.where(name: 'Justice League').last
    # find_or_create_by_
    Rails 3: Team.find_or_create_by_name('Justice League')
    Rails 4: Team.where(name: 'Justice League').first_or_create
    # find_or_initialize_by_
    Rails 3: Team.find_or_initialize_by_name('Justice League')
    Rails 4: Team.where(name: 'Justice League').first_or_initialize
    # scoped_by_
    Rails 3: Team.scoped_by_name('Justice League')
    Rails 4: Team.where(name: 'Justice League')
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35. DEPRECATED HASH FINDERS
    Rails 3: Team.all(conditions: { name: 'Test' })
    Rails 4: Team.where(name: 'Test')
    Really like this syntax anyways? Okay then...
    gem “activerecord-deprecated_finders”
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36. PATCH, NOT PUT
    RFC 5789 technically describes PATCH as a partial update,
    what everyone is using PUT for today.
    Default for update will now be PATCH.
    https://github.com/rails/rails/pull/505
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37. PLAY WITH RAILS 4 NOW
    $ git clone http://github.com/rails/rails.git
    $ cd rails && bundle install
    $ ruby railties/bin/rails new ../try_four --dev
    $ cd ../try_four
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38. RESOURCES
    • http://blog.remarkablelabs.com/2012/11/rails-4-countdown-
    to-2013
    • https://speakerdeck.com/kvzb/wtf-rails-4
    • http://blog.wyeworks.com/2012/10/29/rails-4-in-30-minutes/
    • http://edgeguides.rubyonrails.org/4_0_release_notes.html
    • http://afreshcup.com/
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39. THANKS!
    QUESTIONS?
    Ben Hughes
    @rubiety
    http://benhugh.es
    Thursday, February 7, 13
    

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