Tricks that Rails didn't tell you about @ RailsConf 2014

Transcript

1. Tricks that Rails didn’t tell you about
2. Carlos Antonio @cantoniodasilva
3. ~6 years on Rails
4. I’ve participated in several projects with different contexts
5. I’ve seen code
6. I’ve seen complex code
7. I’ve seen duplicated code
8. I’ve seen Rails code reimplemented in apps
9. How often do you see them? All the time. They're everywhere.
10. You get used to it after some time
11. And that’s a big problem People are afraid to deal with code like that.
12. Rails tricks / features
13. That might help you refactor existing code or improve your developer life a bit
16. Web Development Consultancy Mainly focused in Ruby and Rails Based in São Paulo - Brazil
18. ❤️
19. plataformatec/devise
20. plataformatec/simple_form
21. elixir-lang/elixir
22. Rails Core Team ! Carlos Antonio
23. Rails Core Team José Valim Carlos Antonio Rafael França
24. We use pull requests and code review All the f*cking time.
25. We do cross project code review Sometimes, when the time allows us.
26. And it’s usual to learn new things in the process We’re always learning, right?
32. ಠ_ಠ I had to do this talk after this look of disapproval
33. Rails tricks / features Not used by many Not very well known and / or documented
34. What we will see: Active Record Active Model Action Mailer Action View Action Controller Bonus Stuff
35. Active Record
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 :authors, :name, :string, null: false end end # => ActiveRecord::IrreversibleMigration ! 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 :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
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. group counting >> Article.group(:status).count ! SELECT COUNT(*) AS count_all, status AS status FROM "articles" GROUP BY status ! => {"draft"=>7, "published"=>2}
47. group counting: multiple attrs >> 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}
48. first! relation = Article.where(title: 'UNKNOWN') ! relation.first or raise(ActiveRecord::RecordNotFound, 'ZOMG not found') # => ZOMG Article found (ActiveRecord::RecordNotFound) ! relation.first! # => ActiveRecord::RecordNotFound
49. last! relation = Article.where(title: 'UNKNOWN') ! relation.last or raise(ActiveRecord::RecordNotFound, 'ZOMG not found') # => ZOMG Article found (ActiveRecord::RecordNotFound) ! relation.last! # => ActiveRecord::RecordNotFound
50. 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')
51. 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')
52. eager load strategies >> Article.includes(:author) ! SELECT "articles".* FROM "articles" ! SELECT "authors".* FROM "authors" WHERE "authors"."id" IN (980190962, 298486374)
53. eager load strategies >> 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
54. eager load strategies >> 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"
55. eager load strategies >> Article.preload(:author) ! SELECT "articles".* FROM “articles" ! SELECT "authors".* FROM “authors" WHERE "authors"."id" IN (980190962, 298486374)
56. eager load strategies >> 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)
57. 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
58. 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
59. pluck >> Author.all.map(&:name) ! SELECT "authors".* FROM "authors" ! => ["Author 2", "Author 1"]
60. pluck >> Author.select(:name).map(&:name) ! SELECT "authors"."name" FROM "authors" ! => ["Author 2", "Author 1"]
61. pluck >> Author.pluck(:name) ! SELECT "authors"."name" FROM "authors" ! => ["Author 2", "Author 1"]
62. pluck: multiple attrs >> Author.pluck(:name, :active) ! SELECT "authors"."name", "authors"."active" FROM "authors" ! => [["Author 2", true], ["Author 1", true]]
63. pluck: distinct values >> Author.distinct.pluck(:name) ! SELECT DISTINCT "authors"."name" FROM "authors" ! => ["Author 2", "Author 1"]
64. to_param class Article < ActiveRecord::Base def to_param "#{id}-#{title.parameterize}" end end ! >> Article.all.map(&:to_param) => ["113629430-autoload", "281110143-rails-4-2-0-is-going-to-be-more-adequate", "298486374-rails-4-1-0-released", "980190962-rails-tricks"]
65. to_param class Article < ActiveRecord::Base to_param :title end ! ! ! >> Article.all.map(&:to_param) => ["113629430-autoload", "281110143-rails-4-2-0-is", "298486374-rails-4-1-0-released", "980190962-rails-tricks"]
66. exists?/any? vs present? <% if @author.articles.exists? %> <%= render @author.articles %> <% else %> <p>No article found.</p> <% end %>
67. exists?/any? vs present? >> author = Author.first ! >> author.articles.exists? ! SELECT 1 AS one FROM "articles" WHERE "articles"."author_id" = ? LIMIT 1 [["author_id", 298486374]] ! => true ! >> author.articles.each {} ! SELECT "articles".* FROM "articles" WHERE "articles"."author_id" = ? [["author_id", 298486374]]
68. exists?/any? vs present? >> author = Author.first ! >> author.articles.present? ! SELECT "articles".* FROM "articles" WHERE "articles"."author_id" = ? [["author_id", 298486374]] ! => true ! >> author.articles.each {} ! # => already loaded, so no query
69. benchmark class Article < ActiveRecord::Base def self.expensive_operation sleep 2 'did something very expensive' end end
70. 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
71. benchmark >> ActiveRecord::Base.benchmark 'SUPER EXPENSIVE OPERATION' do ?> Article.expensive_operation >> end SUPER EXPENSIVE OPERATION (2000.9ms) => "did something very expensive"
72. benchmark class Article < ActiveRecord::Base def self.expensive_operation benchmark 'SUPER EXPENSIVE OPERATION' do sleep 2 'did something very expensive' end end end
74. http://railsgirlssummerofcode.org/campaign/ And I got a free hug!
75. Active Model
76. ActiveModel::Model class EmailContact attr_accessor :name, :email, :message ! def deliver if name.present? && email.present? && message.present? puts 'deliver email' end end end
77. ActiveModel::Model contact = EmailContact.new contact.name = 'Carlos' contact.email = 'carlos@example.com' contact.message = 'ZOMG' contact.deliver
78. ActiveModel::Model <%= form_for @email_contact … %> ! <%= render @email_contact %>
79. 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
80. 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
81. ActiveModel::Model contact = EmailContact.new( name: 'Carlos', email: 'carlos@example.com', message: 'ZOMG' ) contact.deliver
82. 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"
83. Action Mailer
84. Mailer with 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
85. Mailer with 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 with i18n subject en: subjects: new_article: 'New article just published.'
87. Mailer with i18n subject en: notifier: new_article: subject: 'New article just published.'
88. Mailer with 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 with 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 with i18n subject en: subjects: new_article: 'New article: %{title}.'
91. Mailer with i18n subject en: notifier: new_article: subject: 'New article %{title}.'
92. Mailer with 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 empty collections <% if author.articles.exists? %> <%= render author.articles %> <% else %> <p>No article found.</p> <% end %>
99. render empty collections <%= render(author.articles) || content_tag(:p, 'No article found.') %>
100. partial locals <%= render article, full: true %> <%= render author.articles, full: false %> ! # article partial <%= content_tag_for :article, article do |article| %> <h2><%= article.title %></h2> ! <% if full %> <%= simple_format article.body %> <% else %> <%= truncate article.body %> <% end %> <% end %>
101. partial locals <%= render article, full: true %> <%= render author.articles %> ! # article partial <%= content_tag_for :article, article do |article| %> <h2><%= article.title %></h2> ! <% if local_assigns[:full] %> <%= simple_format article.body %> <% else %> <%= truncate article.body %> <% end %> <% end %>
102. truncate text <%= 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>
103. I18n + html <%= link_to I18n.t('read_more'), article %> ! ! en: read_more: 'read more…' ! ! <a href="/articles/281110143-rails-4-2-0-is"> read more… </a>
104. I18n + html <%= link_to I18n.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>
105. I18n + html <%= link_to raw(I18n.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>
106. I18n + html <%= link_to I18n.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>
107. benchmark <% benchmark 'Rendering articles' do %> <%= sleep(2); render author.articles %> <% end %> ! ! # logger Rendering articles (2005.1ms)
108. Action Controller
109. redirects with params get '/articles/:id' => redirect('/articles/%{id}/edit')
110. exceptions handling $ ls public/*.html ! 404.html 422.html 500.html
111. exceptions handling # config/application.rb ! # Use the app's own router to display error pages. config.exceptions_app = self.routes
112. exceptions handling # config/routes.rb ! get "/404", to: "errors#not_found" get "/422", to: "errors#unprocessable_entity" get "/500", to: "errors#server_error"
113. exceptions handling 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
114. exceptions handling app/views/ errors/ not_found.html.erb server_error.html.erb unprocessable_entity.html.erb layouts/ error.html.erb
115. Bonus Time!
116. Console
117. 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
118. helper >> helper.time_ago_in_words 30.days.ago => "about 1 month" ! >> helper.hello_rails_conf => "Hello RailsConf 2014!" ! >> helper.class => ActionView::Base
119. application console helpers # lib/console_helpers.rb module ConsoleHelpers def a(id) Article.find(id) end end
120. application console helpers # config/application.rb module RailsConf2014 class Application < Rails::Application console do require 'console_helpers' Rails::ConsoleMethods.send :include, ConsoleHelpers end end end
121. application console helpers >> a(113629430) Article Load (0.1ms) SELECT "articles".* FROM "articles" WHERE "articles"."id" = ? LIMIT 1 [["id", 113629430]] ! => #<Article id: 113629430, …>
122. console sandbox $ rails console >> 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 console >> Article.count => 4
123. console sandbox $ rails console --sandbox … Any modifications you make will be rolled back on exit ! ! ! >> exit rollback transaction
124. Annotations
125. annotations class Author < ActiveRecord::Base # TODO: create inactive scope scope :active, -> { where active: true } end ! class Article < ActiveRecord::Base # FIXME: Fix for RailsConf scope :published, -> { where status: 'published' } end ! class AuthorsController < ApplicationController # OPTIMIZE: eager load stuff def show @author = Author.find(params[:id]) end end
126. annotations $ rake notes ! app/controllers/authors_controller.rb: * [2] [OPTIMIZE] eager load stuff ! app/models/article.rb: * [9] [FIXME] Fix for RailsConf ! app/models/author.rb: * [4] [TODO] create inactive scope
127. custom annotations class Notifier < ActionMailer::Base # RAILSCONF: Hello! def new_article end end
128. custom annotations $ rake notes:custom ANNOTATION=RAILSCONF ! app/mailers/notifier.rb: * [4] Hello!
129. Updating Rails
130. rails update gem 'rails', '4.1.0' ! ! $ bundle update …
131. 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 …
132. 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
133. Every single part of Rails has hidden tricks
134. They are sometimes hard to spot
135. But they can make you much more productive
136. So every time you start something new
137. Before ever considering about pattern X, Y or Z
138. Ask yourself: How Rails can help me?
139. Search API Guidelines Google Stack Overflow …
140. Ask Stack Overflow Rails Talk mailing list IRC …
141. Follow Changelogs Release Notes Upgrading Guides Commits (if you can)
142. And if you do find some hidden trick, remember…
143. With great moustache! ! ! ! comes great responsibility
144. Share Tweet Blog post Tell your friends …
145. Contribute Back to Rails
146. And please ping me too! ! @cantoniodasilva
147. Thank you ❤️
148. Stickers! @plataformatec
149. Questions? Get one of these mugs (5 only :D)
150. Tricks that Rails! didn’t tell you about Carlos Antonio - @cantoniodasilva