https://www.lucascaton.com.br/2013/07/02/apresentacao-online-sobre-as-novidades-do-rails-4

1. What's new in Rails 4
Lucas Caton

2. www.lucascaton.com.br

3. 4

4. May 1, 2013
Rails 4.0: Release Candidate 1 released!

5. Ruby 1.8.7
Ruby 1.9.2
Ruby 1.9.3
Ruby 2.0.0

6. RubyGems 2.x

7. ThreadSafety

8. memcache-client
dalli
=> 20% faster
=> ThreadSafe
=> Easier to integrate with NewRelic RPM

9. ActiveRecord
ActiveModel
4

10. #where
Post.find_all_by_title('Rails 4')
Post.where(title: 'Rails 4')

11. #find_or_*
Post.find_or_initialize_by_title('Rails 4')
Post.find_or_initialize_by(title:'Rails4')

12. #update
@post.update_attributes(post_params)
@post.update(post_params)

13. #update_columns
@post.update_attribute(post_params)
@post.update_columns(post_params)
Skip validations!

14. #all
@posts = Post.scoped
@posts = Post.all
ActiveRecord::Relation

15. Scopes
scope :sold, where(state: 'sold')
default_scope where(state: 'available')
scope :sold, ->{ where(state: 'sold') }
default_scope ->{ where(state: 'available') }

16. class User < ActiveRecord::Base
def visible_posts
case role
when 'Country Manager'
Post.where(country: country)
when 'Reviewer'
Post.published
when 'Bad User'
[]
end
end
end

17. @posts = current_user.visible_posts
if @posts.any?
@posts.recent
else
[]
end

18. #none
class User < ActiveRecord::Base
def visible_posts
case role
when 'Country Manager'
Post.where(country: country)
when 'Reviewer'
Post.published
when 'Bad User'
Post.none
end
end
end

19. #not
if author
Post.where('author != ?', author)
else
Post.where('author IS NOT NULL')
end
Post.where.not(author: author)

20. #order
User.order('created_at DESC')
User.order(:name, 'created_at DESC')
User.order(created_at: :desc)
User.order(:name, created_at: :desc)

21. ActiveModel
4

22. ActiveModel
class SupportTicket
include ActiveModel::Conversion
include ActiveModel::Validations
extend ActiveModel::Naming
extend ActiveModel::Translation
attr_accessor :title, :description
validates_presence_of :title
validates_presence_of :description
end

23. ActiveModel
class SupportTicket
include ActiveModel::Model
attr_accessor :title, :description
validates_presence_of :title
validates_presence_of :description
end

24. Strong
Parameters
4

25. class User < ActiveRecord::Base
attr_accessible :name
end
# Controller
def update
if @user.update_attributes(params[:user])
redirect_to @user, notice: 'Updated'
end
end

26. Strong Parameters
class User < ActiveRecord::Base
end
# Controller
def update
user_params = params.require(:user).permit(:name)
if @user.update(params[:user])
redirect_to @user, notice: 'Updated'
end
end

27. Routes
4

28. match '/items/:id/purchase', to: 'items#purchase'
XSS Attack (Cross-site Scripting)
post '/items/:id/purchase', to: 'items#purchase'
match '/items/:id/purchase', to: 'items#purchase', via: :post
match '/items/:id/purchase', to: 'items#purchase', via: :all

29. PATCH Method for HTTP
Abstract
Several applications extending the Hypertext Transfer
Protocol (HTTP) require a feature to do partial resource
modification. The existing HTTP PUT method only allows
a complete replacement of a document. This proposal
adds a new HTTP method, PATCH, to modify an existing
HTTP resource.
http://tools.ietf.org/html/rfc5789

30. $ rake routes
items GET /items(.:format) items#index
POST /items(.:format) items#create
new_item GET /items/new(.:format) items#new
edit_item GET /items/:id/edit(.:format) items#edit
item GET /items/:id(.:format) items#show
PUT /items/:id(.:format) items#update
PATCH /items/:id(.:format) items#update
DELETE /items/:id(.:format) items#destroy
PATCH HTTP verb

31. Action
Controller
4

32. #before_action
before_filter :set_user, only: [:update]
before_action :set_user, only: [:update]

33. Encrypted cookie stored
in the browser

34. Flash messages
<p id="notice"><%= flash[:notice] %></p>
<p id="notice"><%= notice %></p>

35. Streaming

36. Views
4

37. collections helpers
<% @owners.each do |owner| %>
<%= radio_button_tag :owner_id, owner.id %>
<%= owner.name %>
<% end %>
collection_radio_buttons(:item, :owner_id, @owners, :id, :name)
collection_check_boxes(:item, :owner_id, @owners, :id, :name)

38. date fields
<%= f.date_field :return_date %>
<input id="item_return_date" name="item[return_date]" type="date">

39. date fields
<%= f.date_field :return_date %>

40. TurboLinks
aka. full page pjax

41. Other improvements
=> Routing Concerns
=> Test Folder Structure
=> Caching improvements
=> Custom Flash Types
=> ActionController Live
=> ETags
=> jbuilder template handler

42. Links
Rails Guides - Upgrading from Rails 3.2 to Rails 4.0:
http://edgeguides.rubyonrails.org/
upgrading_ruby_on_rails.html#upgrading-from-rails-3-2-to-
rails-4-0
Rails Casts - Upgrading to Rails 4
http://railscasts.com/episodes/415-upgrading-to-rails-4
Code School - Learn Rails 4 best practices
http://www.codeschool.com/courses/rails-4-zombie-
outlaws

43. Thank you!