Rails 4 Countdown

I’m Rida @rida

I work here

I’m Kevin @kfaustino

I work here

Deprecations

vendor/plugins

Active Record Session Store

activerecord-session_store

Remove # config/initializers/session_store.rb Example::Application.config.session_store :active_record_store

Replace With # config/initializers/session_store.rb Example::Application.config.session_store :encrypted_cookie_store, key: '_example_session'

Use a Key-Value Store

Page & Action Caching

actionpack-page_caching actionpack-action_caching

Use Russian Doll Caching

Observers

rails-observers

Active Resource

activeresource

Dynamic Finders

activerecord-deprecated_ﬁnders

hash syntax # Previous Versions Post.find(:all, conditions: { published_on: 2.weeks.ago
}, limit: 5) # Rails 4 Post.where(:published_on: 2.weeks.ago).limit(5)

ﬁnd_all_by_* # Previous Versions Team.find_all_by_name('Justice League') # Rails 4 Team.where(name:
'Justice League')

ﬁnd_last_by_* # Previous Versions Rails 3: Team.find_last_by_name('Justice League') # Rails
4 Rails 4: Team.where(name: 'Justice League').last

ﬁnd_or_create_by_* # Previous Versions Team.find_or_create_by_name('Justice League') # Rails 4 Team.where(name:
'Justice League').first_or_create

ﬁnd_or_initialize_by # Previous Versions Team.find_or_initialize_by_name('Justice League') # Rails 4 Team.where(name:
'Justice League').first_or_initialize

scoped_by_* # Previous Versions Team.scoped_by_name('Justice League') # Rails 4 Team.where(name:
'Justice League')

Protected Attributes

protected_attributes

Strong Parameters

Rails 3 Way class PeopleController < ApplicationController def create ...
@person = Person.create(params[:person]) ... end end class Person < ActiveRecord::Base attr_accessible :name, :age end

Rails 4 Way class PeopleController < ApplicationController def create ...
@person = Person.create(person_params) ... end private def person_params params.require(:person).permit(:name, :age) end end

require(:key) Fetches the key out of the hash and raises
a ActionController::ParameterMissing error if it's missing.

permit(keys) Selects only the passed keys out of the parameters
hash, and sets the permitted attribute to true.

Available Now! 1. Add the strong_parameters gem to your Gemfile.
2. Set config.active_record.whitelist_attributes = false in your application.rb. 3. Add include ActiveModel::ForbiddenAttributesProtection to your models. 4. Update your controllers to filter the params to your needs, for example: params.require(:person).permit(:name, :age).

HTTP PATCH

PUT vs. PATCH "In a PUT request, the enclosed entity
is considered to be a modiﬁed version of the resource stored on the origin server, and the client is requesting that the stored version be replaced. With PATCH, however, the enclosed entity contains a set of instructions describing how a resource currently residing on the origin server should be modiﬁed to produce a new version." RFC 5789

What’s Changing? - PATCH requests are routed to the update
action. (backwards compatible) - Forms will set the hidden ﬁeld _method to :patch on edits.

Turbolinks

What is it? A JavaScript plugin very similar to PJAX
(pushState + AJAX)

How does it work? Turbolinks will perform an HTTP Request
just as the browser would, but then replaces the <title> and<body> currently loaded in the DOM with the response from the server.

Support - Safari 6.0+ - IE10 - Chrome 5.0+ -
Firefox 4.0+

Available Now! 1. Add the turbolinks gem to your Gemﬁle.
2. Require turbolinks in your JavaScript manifest: // app/assets/javascripts/ application.js //= require jquery //= require jquery_ujs //= require turbolinks //= require_tree .

Generate Controller-Wide ETags

etag method class NotesController < ApplicationController etag { current_user.try :id
} def show @note = Note.find(params[:id]) fresh_when(@note) end end

Renaming *_ﬁlter callbacks to *_action

*_action class ArticlesController < ApplicationController before_action :set_article, except: [:index, :new,
:create] ... private def set_article @article = Article.find(params[:id]) end end

Register your own ﬂash types

The Rails 3 Way # app/controllers/users_controller.rb class UsersController < ApplicationController
def create ... flash[:error] = "An error message for the user" redirect_to home_path end end # app/views/home/index <%= flash[:error] %>

add_ﬂash_types # app/controllers/application_controller.rb class ApplicationController ... add_flash_types :error, :another_custom_type end

Like :notice & :ﬂash # app/controllers/users_controller.rb class UsersController < ApplicationController
def create ... redirect_to home_path, error: "An error message for the user" end end # app/views/home/index <%= error %>

Live Streaming

ActionController::Live 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

Requires 1. Code must be Threadsafe 2. A concurrent Ruby
Web Server, ie. Puma 3. Headers must be written before anything is written to the client. 4. Streams must be closed

Routing Concerns

The Rails 3 Way Older::Application.routes.draw do resources :projects do resources
:comments end resources :tasks do resources :comments end resources :articles do resources :comments end end

The Rails 4 Way Newer::Application.routes.draw do concern :commentable do resources
:comments end resources :projects, concerns: :commentable resources :tasks, concerns: :commentable resources :articles, concerns: :commentable end

Cache Digests

Example class Team < ActiveRecord::Base has_many :members end class Member
< ActiveRecord::Base belongs_to :team, touch: true end

View  <% cache @team do%> <h1>Team: <%=
@team.name %></h1> <%= render @team.members %> <% end %>  <% cache member do %> <div class='member'> <%= member.name %> <p><%= member.bio %></p> </div> <% end %>

key = Model Cache Key + digest of the template
and its dependencies views/members/1-20121220141922/74865fcb3e2752a0928fa4f89b3e4426 views/members/2-20121220141922/74865fcb3e2752a0928fa4f89b3e4426 views/teams/2-20121220141922/4277f85c137009873c093088ef609e60

HTML5 Form Helpers

week_ﬁeld <%= f.week_field :week, min: Time.zone.today.beginning_of_year, max: Time.zone.today.end_of_year %>

month_ﬁeld <%= f.month_field :month %>

datetime_field & datetime_local_field The datetime_field form helper creates an input
of type “datetype”, and accepts time in UTC. The datetime_local_field form helper is the exact same, minus its time is specified in local time.

datetime_ﬁeld & datetime_local_ﬁeld <%= f.datetime_field :birthday %>

time_ﬁeld The time_ﬁeld form helper creates an input of type
“time”. <%= f.time_field :daily_reminder_time %>

date_ﬁeld <%= f.date_field :birthday %>

color_ﬁeld The color_ﬁeld form helper allows users to set a
color via hex values: <%= f.color_field :background_color %>

Collection Form Helpers

Example class Post < ActiveRecord::Base has_many :categories end

collection_check_boxes collection_check_boxes(:post, :category_ids, Category.all, :id, :name) # Returns: # <input
id="post_category_ids_1" name="post[category_ids][]" # type="checkbox" value="1" checked="checked" /> # <label for="post_category_ids_1">Ruby</label> # <input id="post_category_ids_2" name="post[category_ids][]" # type="checkbox" value="2" /> # <label for="post_category_ids_2">Javascript</label> # ... # <input name="post[category_ids][]" type="hidden" value="" /> #

collection_radio_buttons collection_radio_buttons(:post, :category_ids, Category.all, :id, :name) # Returns: # <input
id="post_category_ids_1" name="post[category_ids][]" # type="radio" value="1" checked="checked" /> # <label for="post_category_ids_1">Ruby</label> # <input id="post_category_ids_2" name="post[category_ids][]" # type="radio" value="2" /> # <label for="post_category_ids_2">Javascript</label> # ...

New in ActiveRecord & ActiveModel

ActiveModel::Model

ActiveModel::Model ActiveModel::Model is a module mixin that allows Ruby objects
to work with Action Pack.

ActiveModel::Model Classes that include ActiveModel::Model also get: - Model name
introspections - Conversions - Translations - Validations

Model class Contact include ActiveModel::Model attr_accessor :name, :email, :message validates
:name, presence: true validates :email, presence: true validates :message, presence: true, length: { maximum: 300 } end

View <h1>Contact Us</h1> <%= form_for @contact do |f| %> <%=
f.label :name %> <%= f.text_field :name %> <%= f.label :email %> <%= f.email_field :email %> <%= f.label :message %> <%= f.text_area :message %> <%= f.submit 'Submit' %> <% end %>

Controller class ContactsController < ApplicationController def new @contact = Contact.new
end def create @contact = Contact.new(params[:contact]) if @contact.valid? ContactMailer.new_contact(@contact).deliver redirect_to root_path else render :new end end end

Not Equal Support

The Rails 3 Way Article.where("title != ?", params[:title])

The Rails 4 Way Article.where.not(title: 'Rails 3') # >> SELECT
"articles".* FROM "articles" WHERE ("articles"."title" != 'Rails 3') Article.where.not(title: ['Rails 3', 'Rails 5']) # >> SELECT "articles".* FROM "articles" WHERE ("articles"."title" NOT IN ('Rails 3', 'Rails 5'))

ActiveModel Absence Validator

Example class SuperHero include ActiveModel::Validations attr_accessor :secret_identity validates :secret_identity, absence:
true end

Result super_hero = SuperHero.new super_hero.valid? # => true super_hero.secret_identity =
'Hal Jordan' super_hero.valid? # => false

Null Object Pattern

ActiveRecord::QueryMethods.none Team.none.where(name: 'Justice League') # => #<ActiveRecord::Relation []>

Scopes require a callable object

The Rails 4 Way class Team < ActiveRecord::Base scope :active,
-> { where(status: 'active') } end

#destroy!

#destroy! Active Record now has a #destroy! method to compliment
#create! If a record cannot be destroyed, an ActiveRecord::RecordNotDestroyed exception will be raised.

#update_attributes “Soft” Deprecation

#update @team.update(name: 'X-Men', universe: 'Marvel')

#update_column(s)

#update_column(s) @team.update_column(:name, 'X-Men') @team.update_columns(name: 'X-Men', universe: 'Marvel')

Model.all

Model.all In Rails 4, calls to Model.all is equivalent to
now deprecated Model.scoped.

Default ordering to .ﬁrst

Rails 3 Team.first # SELECT "teams".* FROM "teams" LIMIT 1

Rails 4 Team.first # SELECT "teams".* FROM "teams" ORDER BY
"teams"."id" ASC LIMIT 1

ﬁnd_by and ﬁnd_by!

Mirror Dynamic Finders Member.find_by name: 'Batman', city: 'Gotham' Member.find_by! name:
'Superman'

Multiple columns with Pluck

Pluck Member.pluck(:name, :bio) # >> [["Superman", "From Krypton"], ["Batman", "From
Gotham City"]]

References

Deprecated Team.includes(:members).where('members.name = ?', 'Batman') # Rails 3 SQL (0.7ms)
SELECT "teams"."id" AS t0_r0, "teams"."name" AS t0_r1, "teams"."created_at" AS t0_r2, "teams"."updated_at" AS t0_r3, "members"."id" AS t1_r0, "members"."name" AS t1_r1, "members"."bio" AS t1_r2, "members"."team_id" AS t1_r3, "members"."created_at" AS t1_r4, "members"."updated_at" AS t1_r5 FROM "teams" LEFT OUTER JOIN "members" ON "members"."team_id" = "teams"."id" WHERE (members.name = 'Batman')

Hash Syntax Not Deprecated Team.includes(:members). where(members: { name: 'Batman' })

ActiveRecord::QueryMethods.references Team.includes(:members). where("members.name = ?", 'Batman'). references(:members)

PostgreSQL love

hstore class AddHstoreExtension < ActiveRecord::Migration def up execute 'CREATE EXTENSION
hstore' end def down execute 'DROP EXTENSION hstore' end end

hstore class AddPropertiesToComics < ActiveRecord::Migration def up add_column :comics, :properties,
:hstore end def down remove_column :comics, :properties end end

hstore class Comic < ActiveRecord::Base store_accessor :properties, :story_arc end comic
= Comic.create comic.properties # => nil comic.story_arc = 'Throne of Atlantis' comic.save # => UPDATE "comics" SET "properties" = '"story_arc"=>"Throne of Atlantis"', "updated_at" = '2012-12-29 19:31:45.234882' WHERE "comics"."id" = 1

Query hstore Comic.where("properties -> 'story_arc' = 'Throne of Atlantis'") #
SELECT "comics".* FROM "comics" WHERE (properties -> 'story_arc' = 'Throne of Atlantis')

Array support class AddTagsToArticles < ActiveRecord::Migration def change change_table :articles
do |t| t.string :tags, array: true end end end

Array support article.tags = ['rails'] article.save # UPDATE "articles" SET
"tags" = '{"rails"}', "updated_at" = '2012-12-29 20:12:49.825980' WHERE "articles"."id" = 1 article.reload article.tags # => ["rails"]

Other supported types uuid - Universally unique identiﬁer (UUID) column
type inet - IPv4 Address cidr - IPv6 Address macaddr - MAC addresses json - Nuﬀ said. Ranges - int4range, int8range, numrange, tsrange, tstzrange, daterange

Other Stuﬀ

Ruby >= 1.9.3 minimum!

Threadsafe by default

Dalli replacing memcache-client

Dynamic “Welcome abroad” index page

sprocket-rails

Questions?

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