Eu já participei em
vários projetos com
contextos diferentes
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Eu já vi código
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Eu já vi código complexo
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Eu já vi código duplicado
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Eu já vi código do Rails
reimplementado em apps
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Com que frequência você vê eles?
Todo o tempo. Eles estão em toda parte.
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Você se acostuma com o
código após algum tempo
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E isso é um
grande problema
As pessoas têm medo de lidar com esse tipo de código.
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Rails tricks / features
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Que podem te ajudar a
refatorar código existente
ou melhorar sua vida como desenvolvedor um pouquinho
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No content
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No content
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Consultoria em
Desenvolvimento Web
Com foco principal em Ruby e Rails
São Paulo - Brazil
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❤️
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plataformatec/devise
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plataformatec/simple_form
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elixir-lang/elixir
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Rails Core Team
! Carlos Antonio
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Rails Core Team
José Valim Carlos Antonio Rafael França
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Nós usamos pull requests !
e code review
All the f*cking time.
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Nós fizemos code review
de diferentes projetos
Sempre que o tempo nos permite.
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E é comum aprender
coisas novas no processo
Estamos sempre aprendendo, certo?
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No content
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No content
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No content
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No content
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ಠ_ಠ
Eu tive que criar este talk depois disso.
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Rails tricks / features
Não usadas por muitos
Não muito conhecidas e / ou documentadas
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O que vamos ver:
Active Record
Active Model
Action Mailer
Action View
Action Controller
Bonus Stuff
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Active Record
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migrations: change column null
class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
def up
change_column :authors, :name, :string, null: false
end
!
def down
change_column :authors, :name, :string, null: true
end
end
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migrations: change column null
class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
def up
change_column_null :authors, :name, false
end
!
def down
change_column_null :authors, :name, true
end
end
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migrations: change column null
class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
def change
change_column :authors, :name, :string, null: false
end
end
# => ActiveRecord::IrreversibleMigration
!
class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
def change
change_column_null :authors, :name, false
end
end
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migrations: change column default
class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
def up
change_column :articles, :status, :string, default: 'draft'
end
!
def down
change_column :articles, :status, :string, default: 'published'
end
end
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migrations: change column default
class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
def up
change_column_default :articles, :status, 'draft'
end
!
def down
change_column_default :articles, :status, 'published'
end
end
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migrations: change column default
class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
def change
change_column :articles, :status, :string, default: 'draft'
end
end
# => ActiveRecord::IrreversibleMigration
!
class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
def change
change_column_default :articles, :status, 'draft'
end
end
# => ActiveRecord::IrreversibleMigration
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Relation#merge
class Author < ActiveRecord::Base
has_many :articles
!
scope :with_draft_articles, -> {
uniq.joins(:articles).
where(articles: { status: 'draft' })
}
end
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Relation#merge
>> Author.with_draft_articles.to_sql
!
SELECT DISTINCT "authors".*
FROM "authors"
INNER JOIN "articles" ON "articles"."author_id" = "authors"."id"
WHERE "articles"."status" = 'draft'
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Relation#merge
class Author < ActiveRecord::Base
has_many :articles
!
scope :with_draft_articles, -> {
uniq.joins(:articles).merge(Article.draft)
}
end
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Relation#merge
>> Author.with_draft_articles.to_sql
!
SELECT DISTINCT "authors".*
FROM "authors"
INNER JOIN "articles" ON "articles"."author_id" = "authors"."id"
WHERE "articles"."status" = 'draft'
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group counting
>> Article.group(:status).count
!
SELECT COUNT(*) AS count_all, status AS status
FROM "articles"
GROUP BY status
!
=> {"draft"=>7, "published"=>2}
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group counting: múltiplos atributos
>> Article.group(:status, :category).count
!
SELECT COUNT(*) AS count_all,
status AS status, category AS category
FROM "articles"
GROUP BY status, category
!
=> {["draft", nil]=>5, ["draft", "Talks"]=>2,
["published", "News"]=>1, ["published", "Releases"]=>1}
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first!
relation = Article.where(title: 'UNKNOWN')
!
relation.first or raise(ActiveRecord::RecordNotFound, 'ZOMG not found')
# => ZOMG Article found (ActiveRecord::RecordNotFound)
!
relation.first!
# => ActiveRecord::RecordNotFound
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last!
relation = Article.where(title: 'UNKNOWN')
!
relation.last or raise(ActiveRecord::RecordNotFound, 'ZOMG not found')
# => ZOMG Article found (ActiveRecord::RecordNotFound)
!
relation.last!
# => ActiveRecord::RecordNotFound
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where.not
class Article < ActiveRecord::Base
scope :not_draft, -> { where 'status != ?', 'draft' }
end
!
>> Article.not_draft.to_sql
!
SELECT "articles".*
FROM "articles"
WHERE (status != 'draft')
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where.not
class Article < ActiveRecord::Base
scope :not_draft, -> { where.not status: 'draft' }
end
!
>> Article.not_draft.to_sql
!
SELECT "articles".*
FROM "articles"
WHERE ("articles"."status" != 'draft')
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estratégias de eager load
>> Article.includes(:author)
!
SELECT "articles".* FROM "articles"
!
SELECT "authors".* FROM "authors"
WHERE "authors"."id" IN (980190962, 298486374)
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estratégias de eager load
>> Article.includes(:author).order('authors.name')
!
SELECT "articles"."id" AS t0_r0 ………… "authors"."updated_at" AS t1_r4
FROM "articles"
LEFT OUTER JOIN "authors" ON "authors"."id" = “articles"."author_id"
ORDER BY authors.name
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estratégias de eager load
>> Article.eager_load(:author)
!
SELECT "articles"."id" AS t0_r0 ………… "authors"."updated_at" AS t1_r4
FROM “articles"
LEFT OUTER JOIN "authors" ON "authors"."id" = “articles"."author_id"
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estratégias de eager load
>> Article.preload(:author)
!
SELECT "articles".* FROM “articles"
!
SELECT "authors".* FROM “authors"
WHERE "authors"."id" IN (980190962, 298486374)
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estratégias de eager load
>> Article.preload(:author).joins(:author).order('authors.name')
!
SELECT "articles".*
FROM "articles"
INNER JOIN "authors" ON "authors"."id" = "articles"."author_id"
ORDER BY authors.name
!
SELECT "authors".*
FROM "authors"
WHERE "authors"."id" IN (980190962, 298486374)
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order :asc/:desc
class Article < ActiveRecord::Base
scope :recent, -> { order 'created_at DESC' }
end
!
>> Article.recent
!
SELECT "articles".* FROM "articles"
ORDER BY created_at DESC
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order :asc/:desc
class Article < ActiveRecord::Base
scope :recent, -> { order created_at: :desc }
end
!
>> Article.recent
!
SELECT "articles".* FROM "articles"
ORDER BY "articles"."created_at" DESC
benchmark
>> ActiveRecord::Base.benchmark 'SUPER EXPENSIVE OPERATION' do
?> Article.expensive_operation
>> end
SUPER EXPENSIVE OPERATION (2000.9ms)
=> "did something very expensive"
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benchmark
class Article < ActiveRecord::Base
def self.expensive_operation
benchmark 'SUPER EXPENSIVE OPERATION' do
sleep 2
'did something very expensive'
end
end
end
ActiveModel::Model
class EmailContact
attr_accessor :name, :email, :message
!
def deliver
if name.present? && email.present? && message.present?
puts 'deliver email'
end
end
end
ActiveModel::Model
class EmailContact
extend ActiveModel::Naming
extend ActiveModel::Translation
include ActiveModel::Validations
include ActiveModel::Conversion
!
attr_accessor :name, :email, :message
validates :name, :email, :message, presence: true
!
def deliver
if valid?
puts 'deliver email'
end
end
!
def persisted?
false
end
end
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ActiveModel::Model
class EmailContact
include ActiveModel::Model
!
attr_accessor :name, :email, :message
validates :name, :email, :message, presence: true
!
def deliver
if valid?
puts 'deliver email'
end
end
end
ActiveModel::Model
>> contact = EmailContact.new
=> #
!
>> contact.valid?
=> false
!
>> contact.errors.full_messages.to_sentence
=> "Name can't be blank, Email can't be blank, and
Message can't be blank"
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Action Mailer
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Mailer com i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
# Subject can be set in your I18n file at config/locales/en.yml
# with the following lookup:
#
# en.notifier.new_article.subject
#
def new_article
@greeting = "Hi"
!
mail to: "to@example.org"
end
end
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Mailer com i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
!
!
!
!
!
def new_article
@greeting = "Hi"
!
mail to: "to@example.org", subject: I18n.t('subjects.new_article')
end
end
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Mailer com i18n subject
en:
subjects:
new_article: 'New article just published.'
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Mailer com i18n subject
en:
notifier:
new_article:
subject: 'New article just published.'
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Mailer com i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
def new_article
@greeting = "Hi"
!
mail to: "to@example.org"
end
end
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Mailer com i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
def new_article
@greeting = "Hi"
!
mail to: "to@example.org",
subject: I18n.t('subjects.new_article', title: 'Clarity is king')
end
end
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Mailer com i18n subject
en:
subjects:
new_article: 'New article: %{title}.'
Mailer com i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
def new_article
@greeting = "Hi"
!
mail to: "to@example.org",
subject: default_i18n_subject(title: 'Clarity is king')
end
end
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Action View
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content_tag_for
<%= content_tag_for :article, @articles do |article| %>
<%= article.title %>
<%= simple_format article.body %>
<% end %>
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content_tag_for
Rails 4.2.0 is going to be more Adequate
Rails 4.2.0 is going to be made more Adequate by
Tenderlove and Gorby Puff
Rails 4.1.0 Released
Rails 4.1.0 was just released before RailsConf
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content_tag_for
<%= content_tag_for :section, @author do |author| %>
<%= author.name %>
…
<% end %>
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content_tag_for
Author 2
…
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render com coleções vazias
<% if author.articles.exists? %>
<%= render author.articles %>
<% else %>
redirects com parâmetros
get '/articles/:id' => redirect('/articles/%{id}/edit')
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tratamento de exceções
$ ls public/*.html
!
404.html 422.html 500.html
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tratamento de exceções
# config/application.rb
!
# Use the app's own router to display error pages.
config.exceptions_app = self.routes
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tratamento de exceções
# config/routes.rb
!
get "/404", to: "errors#not_found"
get "/422", to: "errors#unprocessable_entity"
get "/500", to: "errors#server_error"
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tratamento de exceções
class ErrorsController < ApplicationController
layout "error"
!
def not_found
render status: :not_found
end
!
def server_error
render status: :server_error
end
!
def unprocessable_entity
render status: :unprocessable_entity
end
end
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tratamento de exceções
app/views/
errors/
not_found.html.erb
server_error.html.erb
unprocessable_entity.html.erb
layouts/
error.html.erb
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Bonus Time!
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Console
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app
>> app.author_path(Author.first)
=> “/authors/298486374"
!
>> app.get _
Started GET "/authors/298486374" for 127.0.0.1 at 2014-04-22 19:31:04
-0500
Processing by AuthorsController#show as HTML
…
Rendered authors/show.html.erb within layouts/application (1.1ms)
Completed 200 OK in 9ms (Views: 7.7ms | ActiveRecord: 0.2ms)
=> 200
!
>> app.class
=> ActionDispatch::Integration::Session
console helpers da aplicação
# lib/console_helpers.rb
module ConsoleHelpers
def a(id)
Article.find(id)
end
end
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console helpers da aplicação
# config/application.rb
module RailsConf2014
class Application < Rails::Application
console do
require 'console_helpers'
Rails::ConsoleMethods.send :include, ConsoleHelpers
end
end
end
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console helpers da aplicação
>> a(113629430)
Article Load (0.1ms) SELECT "articles".* FROM "articles"
WHERE "articles"."id" = ? LIMIT 1 [["id", 113629430]]
!
=> #
console sandbox
$ rails console --sandbox
…
Any modifications you make will be rolled back on exit
!
!
!
>> exit
rollback transaction
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Annotations
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notas
class Author < ActiveRecord::Base
# TODO: create inactive scope
scope :active, -> { where active: true }
end
!
class Article < ActiveRecord::Base
# FIXME: Fix this
scope :published, -> { where status: 'published' }
end
!
class AuthorsController < ApplicationController
# OPTIMIZE: eager load stuff
def show
@author = Author.find(params[:id])
end
end
rails update
$ rake rails:update
identical config/boot.rb
exist config
conflict config/routes.rb
./railsconf2014-404/config/routes.rb? (enter "h" for help) [Ynaqdh] h
Y - yes, overwrite
n - no, do not overwrite
a - all, overwrite this and all others
q - quit, abort
d - diff, show the differences between the old and the new
h - help, show this help
./railsconf2014-404/config/routes.rb? (enter "h" for help) [Ynaqdh] a
force config/routes.rb
…
exist config/initializers
identical config/initializers/backtrace_silencers.rb
create config/initializers/cookies_serializer.rb
identical config/initializers/filter_parameter_logging.rb
…
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rails update
$ git status
On branch master
Changes not staged for commit:
(use "git add ..." to update what will be committed)
(use "git checkout -- ..." to discard changes in working directory)
!
modified: Gemfile
modified: Gemfile.lock
modified: config/environment.rb
modified: config/environments/development.rb
modified: config/environments/production.rb
modified: config/environments/test.rb
modified: config/initializers/mime_types.rb
modified: config/initializers/session_store.rb
modified: config/routes.rb
!
Untracked files:
(use "git add ..." to include in what will be committed)
!
config/initializers/cookies_serializer.rb
config/secrets.yml
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Cada parte do Rails tem
seus truques escondidos
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Eles são às vezes
difíceis de achar
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Mas eles podem te deixar
muito mais produtivo
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Então toda vez que você
começar algo novo
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Antes mesmo de considerar
usar o pattern X, Y ou Z
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Pergunte-se: Como o
Rails pode me ajudar?
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Pesquise
API
Guidelines
Google
Stack Overflow
…
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Pergunte
Stack Overflow
Rails Talk mailing list
IRC
…