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

Transcript

1. Os truques que o Rails
   não te contou
   

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2. Carlos Antonio
   @cantoniodasilva
   

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4. ~6 anos
   Ruby / Rails
   

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5. Eu já participei em
   vários projetos com
   contextos diferentes
   

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6. Eu já vi código
   

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7. Eu já vi código complexo
   

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8. Eu já vi código duplicado
   

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9. !
   Eu já vi código do Rails
   reimplementado em apps
   

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10. Com que frequência você vê eles?
    Todo o tempo. Eles estão em toda parte.
    

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11. Você se acostuma com o
    código após algum tempo
    

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12. E isso é um grande problema
    As pessoas têm medo de lidar com esse tipo de código.
    

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13. Rails tricks / features
    Não usadas por muitos
    Não muito conhecidas e / ou documentadas
    

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14. Que podem te ajudar a
    refatorar código existente
    ou melhorar sua vida como desenvolvedor um pouquinho.
    

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15. TDD
    IS DEAD
    

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17. Devise
    Rails Summit 2009
    

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20. http://blog.plataformatec.com.br/2014/08/thank-you-carlos-antonio/
    

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21. https://www.enjoei.com.br
    

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23. A Plataformatec usa
    pull requests e code review
    All the f*cking time.
    

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24. E é comum aprender
    coisas novas no processo
    Estamos sempre aprendendo, certo?
    

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30. ಠ_ಠ
    Eu tive que criar este talk depois disso.
    

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31. O que vamos ver:
    Active Record
    Active Model
    Action Mailer
    !
    Action View
    Action Controller
    Bonus Stuff
    

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32. Active Record
    

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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
    

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34. migrations: revert
    class DropAuthorsActive < ActiveRecord::Migration
    def change
    remove_column :authors, :active
    end
    end
    # => ActiveRecord::IrreversibleMigration
    

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35. migrations: revert
    class DropAuthorsActive < ActiveRecord::Migration
    def change
    revert do
    add_column :authors, :active, :boolean, default: true
    end
    end
    end
    

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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
    

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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
    

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38. migrations: change column null
    class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
    def change
    change_column_null :authors, :name, false
    end
    end
    

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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
    

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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
    

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41. migrations: change column default
    class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
    def change
    change_column_default :articles, :status, 'draft'
    end
    end
    # => ActiveRecord::IrreversibleMigration
    

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42. 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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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'
    

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44. Relation#merge
    class Author < ActiveRecord::Base
    has_many :articles
    !
    scope :with_draft_articles, -> {
    uniq.joins(:articles).merge(Article.draft)
    }
    end
    

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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'
    

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46. find_by
    >> Article.where(title: 'ZOMG').first
    => #
    !
    >> Article.find_by(title: 'ZOMG')
    => #
    

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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')
    

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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')
    

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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
    

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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
    

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51. 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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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
    

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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"
    

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54. 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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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)
    

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56. 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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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}
    

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58. pluck
    >> Author.all.map(&:name)
    !
    SELECT "authors".* FROM "authors"
    !
    => ["Author 2", "Author 1"]
    

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59. pluck
    >> Author.select(:name).map(&:name)
    !
    SELECT "authors"."name" FROM "authors"
    !
    => ["Author 2", "Author 1"]
    

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60. pluck
    >> Author.pluck(:name)
    !
    SELECT "authors"."name" FROM "authors"
    !
    => ["Author 2", "Author 1"]
    

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61. pluck: múltiplos atributos
    >> Author.pluck(:name, :active)
    !
    SELECT "authors"."name", "authors"."active"
    FROM "authors"
    !
    => [["Author 2", true], ["Author 1", true]]
    

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62. pluck: valores distintos
    >> Author.distinct.pluck(:name)
    !
    SELECT DISTINCT "authors"."name" FROM "authors"
    !
    => ["Author 2", "Author 1"]
    

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63. exists?/any? vs present?
    <% if @author.articles.exists? %>
    <%= render @author.articles %>
    <% else %>
    No article found.
    <% end %>
    

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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
    

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65. exists?/any? vs present?
    >> author.articles.each {}
    !
    SELECT "articles".* FROM "articles"
    WHERE "articles"."author_id" = ? [["author_id", 1]]
    

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66. exists?/any? vs present?
    >> author = Author.first
    !
    >> author.articles.present?
    !
    SELECT "articles".* FROM "articles"
    WHERE "articles"."author_id" = ? [["author_id", 1]]
    !
    => true
    

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67. exists?/any? vs present?
    >> author.articles.each {}
    !
    # => já carregado, não dispara outra query
    

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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]]
    

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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
    

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70. benchmark
    class Article < ActiveRecord::Base
    def self.expensive_operation
    sleep 2
    'did something very expensive'
    end
    end
    

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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
    

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72. 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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73. benchmark
    class Article < ActiveRecord::Base
    def self.expensive_operation
    benchmark 'SUPER EXPENSIVE OPERATION' do
    sleep 2
    'did something very expensive'
    end
    end
    end
    

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74. Active Model
    

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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
    

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76. ActiveModel::Model
    contact = EmailContact.new
    contact.name = 'Carlos'
    contact.email = 'carlos@example.com'
    contact.message = 'ZOMG'
    contact.deliver
    

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77. ActiveModel::Model
    <%= form_for @email_contact … %>
    !
    <%= render @email_contact %>
    

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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
    

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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
    

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80. ActiveModel::Model
    contact = EmailContact.new(
    name: 'Carlos',
    email: 'carlos@example.com',
    message: 'ZOMG'
    )
    contact.deliver
    

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81. 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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82. Action Mailer
    

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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
    

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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
    

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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
    

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86. Mailer com i18n subject
    en:
    subjects:
    new_article: 'New article just published.'
    

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87. Mailer com i18n subject
    en:
    notifier:
    new_article:
    subject: 'New article just published.'
    

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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
    

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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
    

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90. Mailer com i18n subject
    en:
    subjects:
    new_article: 'New article: %{title}.'
    

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91. Mailer com i18n subject
    en:
    notifier:
    new_article:
    subject: 'New article %{title}.'
    

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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
    

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93. Action View
    

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94. content_tag_for
    <%= content_tag_for :article, @articles do |article| %>
    <%= article.title %>
    <%= simple_format article.body %>
    <% end %>
    

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95. 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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96. content_tag_for
    <%= content_tag_for :section, @author do |author| %>
    <%= author.name %>
    …
    <% end %>
    

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97. content_tag_for
    
    Author 2
    …
    
    

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98. render com coleções vazias
    <% if author.articles.exists? %>
    <%= render author.articles %>
    <% else %>
    No article found.
    <% end %>
    

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99. render com coleções vazias
    <%= render(author.articles) ||
    content_tag(:p, 'No article found.') %>
    

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100. truncar textos
     <%= truncate article.body do %>
     <%= link_to 'read more...', article %>
     <% end %>
     !
     !
     Rails 4.2.0 is going to be ...
     
     read more…
     
     

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101. I18n + html
     <%= link_to t('read_more'), article %>
     !
     en:
     read_more: 'read more…'
     !
     !
     
     read more…
     
     

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102. I18n + html
     <%= link_to t('read_more'), article %>
     !
     en:
     read_more: 'read more…'
     !
     !
     
     read <b>more</b>…
     
     

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103. I18n + html
     <%= link_to raw(t('read_more')), article %>
     !
     en:
     read_more: 'read more…'
     !
     !
     
     read more…
     
     

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104. I18n + html
     <%= link_to t(‘read_more_html'), article %>
     !
     en:
     read_more_html: 'read more…'
     !
     !
     
     read more…
     
     

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105. benchmark
     <% benchmark 'Rendering articles' do %>
     <%= sleep(2); render author.articles %>
     <% end %>
     !
     !
     # logger
     Rendering articles (2005.1ms)
     

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106. Action Controller
     

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107. redirects com parâmetros
     get '/articles/:id' => redirect('/articles/%{id}/edit')
     

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108. tratamento de exceções
     $ ls public/*.html
     !
     404.html 422.html 500.html
     

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109. 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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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"
     

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111. tratamento de exceções
     class ErrorsController < ApplicationController
     layout "error"
     !
     def not_found
     render status: :not_found
     end
     !
     …
     end
     

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112. 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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113. Console
     

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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
     

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115. helper
     >> helper.time_ago_in_words 30.days.ago
     => "about 1 month"
     !
     >> helper.hello_ruby_conf
     => "Hello RubyConfBR 2014!"
     !
     >> helper.class
     => ActionView::Base
     

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116. console helpers da aplicação
     # lib/console_helpers.rb
     module ConsoleHelpers
     def a(id)
     Article.find(id)
     end
     end
     

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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
     

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118. console helpers da aplicação
     >> a(113629430)
     Article Load (0.1ms) SELECT "articles".* FROM "articles" WHERE
     "articles"."id" = ? LIMIT 1 [["id", 113629430]]
     !
     => #
     

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119. console sandbox
     $ rails runner 'puts Article.count'
     4
     !
     $ rails console --sandbox
     >> Article.create! title: 'I will be rolled back'
     => #
     >> Article.count
     => 5
     !
     $ rails runner 'puts Article.count'
     4
     

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120. console sandbox
     $ rails console --sandbox
     …
     Any modifications you make will be rolled back on exit
     !
     !
     !
     >> exit
     rollback transaction
     

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121. Atualizando Rails
     

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122. rails update
     gem 'rails', '4.1.0'
     !
     !
     $ bundle update
     …
     

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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
     …
     

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124. 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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125. Cada parte do Rails tem
     seus truques escondidos
     

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126. Eles são às vezes
     difíceis de achar
     

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127. Mas eles podem te deixar
     muito mais produtivo
     

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128. Então toda vez que você
     começar algo novo
     

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129. Antes mesmo de considerar
     usar o pattern X, Y ou Z
     

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130. Pergunte-se: Como o Rails
     pode me ajudar?
     

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131. Pesquise
     API
     Guidelines
     Google
     Stack Overflow
     …
     

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132. Pergunte
     Stack Overflow
     Rails Talk mailing list
     IRC
     …
     

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133. Siga
     Changelogs
     Release Notes
     Upgrading Guides
     Commits (se puder)
     

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134. E se você encontrar algum
     truque, lembre-se…
     

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135. View Slide

136. Compartilhe
     Tweet
     Blog post
     Diga aos seus amigos
     …
     

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137. Contribua
     De volta para o Rails
     

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138. E por favor me avise! :)
     !
     @cantoniodasilva
     

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139. Carlos Antonio
     https://speakerdeck.com/carlosantoniodasilva
     @cantoniodasilva
     Os truques que o
     Rails não te contou
     carlosantoniodasilva@gmail.com
     

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