what's new in rails 4

What's new in Rails 4

Lucas Caton

www.lucascaton.com.br

June 25, 2013Rails 4.0: Final version released!

Ruby 1.8.7Ruby 1.9.2Ruby 1.9.3Ruby 2.0.0

RubyGems 2.x

ThreadSafety

memcache-client

dalli=> 20% faster=> ThreadSafe=> Easier to integrate with NewRelic RPM

ActiveRecordActiveModel4

#where

Post.find_all_by_title('Rails 4')

Post.where(title: 'Rails 4')

#!nd_or_*

Post.find_or_initialize_by_title('Rails 4')

Post.find_or_initialize_by(title:'Rails4')

#update

@post.update_attributes(post_params)

@post.update(post_params)

#update_columns

@post.update_attribute(post_params)

@post.update_columns(post_params)

Skip validations!

@posts = Post.scoped

@posts = Post.all

ActiveRecord::Relation

Scopes

scope :sold, where(state: 'sold')default_scope where(state: 'available')

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

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

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

@posts = current_user.visible_posts

if @posts.any? @posts.recentelse []end

#noneclass 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 endend

#notif author Post.where('author != ?', author)else Post.where('author IS NOT NULL')end

Post.where.not(author: author)

#order

User.order('created_at DESC')User.order(:name, 'created_at DESC')

User.order(created_at: :desc)User.order(:name, created_at: :desc)

ActiveModel4

ActiveModelclass SupportTicket include ActiveModel::Conversion include ActiveModel::Validations extend ActiveModel::Naming extend ActiveModel::Translation

attr_accessor :title, :description

validates_presence_of :title validates_presence_of :descriptionend

ActiveModel

class SupportTicket include ActiveModel::Model

attr_accessor :title, :description

validates_presence_of :title validates_presence_of :descriptionend

Strong Parameters4

class User < ActiveRecord::Base attr_accessible :nameend

# Controllerdef update if @user.update_attributes(params[:user]) redirect_to @user, notice: 'Updated' endend

Strong Parametersclass User < ActiveRecord::Baseend

# Controllerdef update user_params = params.require(:user).permit(:name)

Strong Parametersclass User < ActiveRecord::Baseend

# Controllerdef update user_params = params.require(:user).permit(:name)

if @user.update(user_params) redirect_to @user, notice: 'Updated' endend

Routes4

match '/items/:id/purchase', to: 'items#purchase'

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: :postmatch '/items/:id/purchase', to: 'items#purchase', via: :all

PATCH Method for HTTPAbstract

Several applications extending the Hypertext Transfer Protocol (HTTP) require a feature to do partial resource

modi!cation. 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

$ rake routes

items GET /items(.:format) items#index POST /items(.:format) items#createnew_item GET /items/new(.:format) items#newedit_item GET /items/:id/edit(.:format) items#edititem 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

Action Controller4

#before_action

before_filter :set_user, only: [:update]

before_action :set_user, only: [:update]

Encrypted cookie storedin the browser

Flash messages

Streaming

class FooController < ActionController::Base include ActionController::Live

def index 100.times { # Client will see this as it's written response.stream.write "hello world\n" sleep 1 } response.stream.close endend

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)

date !elds

<%= f.date_field :return_date %>

date !elds<%= f.date_field :return_date %>

First request

1. Render body2. Create ETag3. Body & ETag includedin response

First request

headers['ETag'] = Digest::MD5.hexdigest(body)

First request

200 Successheaders['ETag']