Os truques que o Rails não te contou @ RubyConf Brasil 2014

Transcript

1. Os truques que o Rails não te contou
2. Carlos Antonio @cantoniodasilva
4. ~6 anos Ruby / Rails
5. Eu já participei em vários projetos com contextos diferentes
6. Eu já vi código
7. Eu já vi código complexo
8. Eu já vi código duplicado
9. ! Eu já vi código do Rails reimplementado em apps
10. Com que frequência você vê eles? Todo o tempo. Eles estão em toda parte.
11. Você se acostuma com o código após algum tempo
12. E isso é um grande problema As pessoas têm medo de lidar com esse tipo de código.
13. Rails tricks / features Não usadas por muitos Não muito conhecidas e / ou documentadas
14. Que podem te ajudar a refatorar código existente ou melhorar sua vida como desenvolvedor um pouquinho.
15. TDD IS DEAD
17. Devise Rails Summit 2009
20. http://blog.plataformatec.com.br/2014/08/thank-you-carlos-antonio/
21. https://www.enjoei.com.br
23. A Plataformatec usa pull requests e code review All the f*cking time.
24. E é comum aprender coisas novas no processo Estamos sempre aprendendo, certo?
30. ಠ_ಠ Eu tive que criar este talk depois disso.
31. O que vamos ver: Active Record Active Model Action Mailer ! Action View Action Controller Bonus Stuff
32. Active Record
33. migrations: revert class DropAuthorsActive < ActiveRecord::Migration def up remove_column :authors, :active end ! def down add_column :authors, :active, :boolean, default: true end end
34. migrations: revert class DropAuthorsActive < ActiveRecord::Migration def change remove_column :authors, :active end end # => ActiveRecord::IrreversibleMigration
35. migrations: revert class DropAuthorsActive < ActiveRecord::Migration def change revert do add_column :authors, :active, :boolean, default: true end end end
36. 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
37. 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
38. migrations: change column null class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration def change change_column_null :authors, :name, false end end
39. 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
40. 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
41. migrations: change column default class ChangeStatusDefaultOnArticles < ActiveRecord::Migration def change change_column_default :articles, :status, 'draft' end end # => ActiveRecord::IrreversibleMigration
42. Relation#merge class Author < ActiveRecord::Base has_many :articles ! scope :with_draft_articles, -> { uniq.joins(:articles). where(articles: { status: 'draft' }) } end
43. 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'
44. Relation#merge class Author < ActiveRecord::Base has_many :articles ! scope :with_draft_articles, -> { uniq.joins(:articles).merge(Article.draft) } end
45. 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'
46. find_by >> Article.where(title: 'ZOMG').first => #<Article id: 113629430 ...> ! >> Article.find_by(title: 'ZOMG') => #<Article id: 113629430 ...>
47. 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')
48. 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')
49. 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
50. 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
51. estratégias de eager load >> Article.includes(:author) ! SELECT "articles".* FROM "articles" ! SELECT "authors".* FROM "authors" WHERE "authors"."id" IN (980190962, 298486374)
52. 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
53. 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"
54. estratégias de eager load >> Article.preload(:author) ! SELECT "articles".* FROM “articles" ! SELECT "authors".* FROM “authors" WHERE "authors"."id" IN (980190962, 298486374)
55. 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)
56. group counting >> Article.group(:status).count ! SELECT COUNT(*) AS count_all, status AS status FROM "articles" GROUP BY status ! => {"draft"=>7, “published"=>2}
57. 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}
58. pluck >> Author.all.map(&:name) ! SELECT "authors".* FROM "authors" ! => ["Author 2", "Author 1"]
59. pluck >> Author.select(:name).map(&:name) ! SELECT "authors"."name" FROM "authors" ! => ["Author 2", "Author 1"]
60. pluck >> Author.pluck(:name) ! SELECT "authors"."name" FROM "authors" ! => ["Author 2", "Author 1"]
61. pluck: múltiplos atributos >> Author.pluck(:name, :active) ! SELECT "authors"."name", "authors"."active" FROM "authors" ! => [["Author 2", true], ["Author 1", true]]
62. pluck: valores distintos >> Author.distinct.pluck(:name) ! SELECT DISTINCT "authors"."name" FROM "authors" ! => ["Author 2", "Author 1"]
63. exists?/any? vs present? <% if @author.articles.exists? %> <%= render @author.articles %> <% else %> <p>No article found.</p> <% end %>
64. exists?/any? vs present? >> author = Author.first ! >> author.articles.exists? ! SELECT 1 AS one FROM "articles" WHERE "articles"."author_id" = ? LIMIT 1 [["author_id", 1]] ! => true
65. exists?/any? vs present? >> author.articles.each {} ! SELECT "articles".* FROM "articles" WHERE "articles"."author_id" = ? [["author_id", 1]]
66. exists?/any? vs present? >> author = Author.first ! >> author.articles.present? ! SELECT "articles".* FROM "articles" WHERE "articles"."author_id" = ? [["author_id", 1]] ! => true
67. exists?/any? vs present? >> author.articles.each {} ! # => já carregado, não dispara outra query
68. association count vs size >> author = Author.first ! >> author.articles.count SELECT COUNT(*) FROM "articles" WHERE "articles"."author_id" = ? [["author_id", 1]] ! >> author.articles.size SELECT COUNT(*) FROM "articles" WHERE "articles"."author_id" = ? [["author_id", 1]]
69. association count vs size >> author = Author.includes(:articles).first ! >> author.articles.count SELECT COUNT(*) FROM "articles" WHERE "articles"."author_id" = ? [["author_id", 1]] ! >> author.articles.size ! # => já carregado, não dispara outra query
70. benchmark class Article < ActiveRecord::Base def self.expensive_operation sleep 2 'did something very expensive' end end
71. benchmark >> start = Time.now => 2014-04-21 10:48:30 -0500 >> Article.expensive_operation => "did something very expensive" >> finish = Time.now => 2014-04-21 10:48:32 -0500 >> finish - start => 2.02356
72. benchmark >> ActiveRecord::Base.benchmark 'SUPER EXPENSIVE OPERATION' do ?> Article.expensive_operation >> end SUPER EXPENSIVE OPERATION (2000.9ms) => "did something very expensive"
73. benchmark class Article < ActiveRecord::Base def self.expensive_operation benchmark 'SUPER EXPENSIVE OPERATION' do sleep 2 'did something very expensive' end end end
74. Active Model
75. ActiveModel::Model class EmailContact attr_accessor :name, :email, :message ! def deliver if name.present? && email.present? && message.present? puts 'deliver email' end end end
76. ActiveModel::Model contact = EmailContact.new contact.name = 'Carlos' contact.email = 'carlos@example.com' contact.message = 'ZOMG' contact.deliver
77. ActiveModel::Model <%= form_for @email_contact … %> ! <%= render @email_contact %>
78. 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
79. 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
80. ActiveModel::Model contact = EmailContact.new( name: 'Carlos', email: 'carlos@example.com', message: 'ZOMG' ) contact.deliver
81. ActiveModel::Model >> contact = EmailContact.new => #<EmailContact:0x007fb90e268350> ! >> 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"
82. Action Mailer
83. 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
84. 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
85. 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
86. Mailer com i18n subject en: subjects: new_article: 'New article just published.'
87. Mailer com i18n subject en: notifier: new_article: subject: 'New article just published.'
88. 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
89. 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
90. Mailer com i18n subject en: subjects: new_article: 'New article: %{title}.'
91. Mailer com i18n subject en: notifier: new_article: subject: 'New article %{title}.'
92. 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
93. Action View
94. content_tag_for <%= content_tag_for :article, @articles do |article| %> <h2><%= article.title %></h2> <%= simple_format article.body %> <% end %>
95. content_tag_for <article class="article" id="article_281110143"> <h2>Rails 4.2.0 is going to be more Adequate</h2> <p>Rails 4.2.0 is going to be made more Adequate by Tenderlove and Gorby Puff</p> </article> <article class="article" id="article_298486374"> <h2>Rails 4.1.0 Released</h2> <p>Rails 4.1.0 was just released before RailsConf</p> </article>
96. content_tag_for <%= content_tag_for :section, @author do |author| %> <h1><%= author.name %></h1> … <% end %>
97. content_tag_for <section class="author" id="author_298486374"> <h1>Author 2</h1> … </section>
98. render com coleções vazias <% if author.articles.exists? %> <%= render author.articles %> <% else %> <p>No article found.</p> <% end %>
99. render com coleções vazias <%= render(author.articles) || content_tag(:p, 'No article found.') %>
100. truncar textos <%= truncate article.body do %> <%= link_to 'read more...', article %> <% end %> ! ! Rails 4.2.0 is going to be ... <a href="/articles/281110143-rails-4-2-0-is"> read more… </a>
101. I18n + html <%= link_to t('read_more'), article %> ! en: read_more: 'read more…' ! ! <a href="/articles/281110143-rails-4-2-0-is"> read more… </a>
102. I18n + html <%= link_to t('read_more'), article %> ! en: read_more: 'read <b>more</b>…' ! ! <a href="/articles/281110143-rails-4-2-0-is"> read &lt;b&gt;more&lt;/b&gt;… </a>
103. I18n + html <%= link_to raw(t('read_more')), article %> ! en: read_more: 'read <b>more</b>…' ! ! <a href="/articles/281110143-rails-4-2-0-is"> read <b>more</b>… </a>
104. I18n + html <%= link_to t(‘read_more_html'), article %> ! en: read_more_html: 'read <b>more</b>…' ! ! <a href="/articles/281110143-rails-4-2-0-is"> read <b>more</b>… </a>
105. benchmark <% benchmark 'Rendering articles' do %> <%= sleep(2); render author.articles %> <% end %> ! ! # logger Rendering articles (2005.1ms)
106. Action Controller
107. redirects com parâmetros get '/articles/:id' => redirect('/articles/%{id}/edit')
108. tratamento de exceções $ ls public/*.html ! 404.html 422.html 500.html
109. tratamento de exceções # config/application.rb ! # Use the app's own router to display error pages. config.exceptions_app = self.routes
110. tratamento de exceções # config/routes.rb ! get "/404", to: "errors#not_found" get "/422", to: "errors#unprocessable_entity" get "/500", to: "errors#server_error"
111. tratamento de exceções class ErrorsController < ApplicationController layout "error" ! def not_found render status: :not_found end ! … end
112. tratamento de exceções app/views/ errors/ not_found.html.erb server_error.html.erb unprocessable_entity.html.erb layouts/ error.html.erb
113. Console
114. 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
115. helper >> helper.time_ago_in_words 30.days.ago => "about 1 month" ! >> helper.hello_ruby_conf => "Hello RubyConfBR 2014!" ! >> helper.class => ActionView::Base
116. console helpers da aplicação # lib/console_helpers.rb module ConsoleHelpers def a(id) Article.find(id) end end
117. console helpers da aplicação # config/application.rb module RubyConf2014 class Application < Rails::Application console do require 'console_helpers' Rails::ConsoleMethods.send :include, ConsoleHelpers end end end
118. console helpers da aplicação >> a(113629430) Article Load (0.1ms) SELECT "articles".* FROM "articles" WHERE "articles"."id" = ? LIMIT 1 [["id", 113629430]] ! => #<Article id: 113629430, …>
119. console sandbox $ rails runner 'puts Article.count' 4 ! $ rails console --sandbox >> Article.create! title: 'I will be rolled back' => #<Article id: 980190968, title: "I will be rolled back", …> >> Article.count => 5 ! $ rails runner 'puts Article.count' 4
120. console sandbox $ rails console --sandbox … Any modifications you make will be rolled back on exit ! ! ! >> exit rollback transaction
121. Atualizando Rails
122. rails update gem 'rails', '4.1.0' ! ! $ bundle update …
123. 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 …
124. rails update $ git status On branch master Changes not staged for commit: (use "git add <file>..." to update what will be committed) (use "git checkout -- <file>..." 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 <file>..." to include in what will be committed) ! config/initializers/cookies_serializer.rb config/secrets.yml
125. Cada parte do Rails tem seus truques escondidos
126. Eles são às vezes difíceis de achar
127. Mas eles podem te deixar muito mais produtivo
128. Então toda vez que você começar algo novo
129. Antes mesmo de considerar usar o pattern X, Y ou Z
130. Pergunte-se: Como o Rails pode me ajudar?
131. Pesquise API Guidelines Google Stack Overflow …
132. Pergunte Stack Overflow Rails Talk mailing list IRC …
133. Siga Changelogs Release Notes Upgrading Guides Commits (se puder)
134. E se você encontrar algum truque, lembre-se…
136. Compartilhe Tweet Blog post Diga aos seus amigos …
137. Contribua De volta para o Rails
138. E por favor me avise! :) ! @cantoniodasilva
139. Carlos Antonio https://speakerdeck.com/carlosantoniodasilva @cantoniodasilva Os truques que o Rails não te contou carlosantoniodasilva@gmail.com