[RailsConf 2023 Opening Keynote] The Magic of Rails

Eileen M. Uchitelle

April 24, 2023

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Transcript

1. The Magic of Rails exploring the principles & techniques behind

   the framework
2. None

3. Hello RailsConf! I'm Eileen M. Uchitelle @eileencodes @[email protected]

4. None
5. None

6. The Magic of Rails exploring the principles & techniques behind

   the framework

7. What is Ruby on Rails?

8. Rails is modular, but 
 not fractured

9. Rails is designed to have agnostic interfaces

10. Rails is extracted from applications

11. Rails is made of 
 simple and aesthetic APIs

12. Rails is a framework that takes on complexity to empower

    you

13. How Rails components are structured

14. RUBY ON RAILS Active Record Active Support Active Model Active

    Job Active Storage Action Mailer Action Pack Action View Action Cable Action Text Action Mailbox Railties

15. Naming Convention Active vs Action

16. Active Record Active Support Active Model Active Job Active Storage

    BACKEND NAMING CONVENTION

17. USER FACING Active Record Active Support Active Model Active Job

    Active Storage BACKEND NAMING CONVENTION Action Mailer Action Pack Action View Action Cable Action Text Action Mailbox USER FACING

18. Active Record Active Support Active Model Active Job Active Storage

    Action Mailer Action Pack Action View Action Cable Action Text Action Mailbox BACKEND USER FACING Railties GLUE NAMING CONVENTION

19. Architeture & Patterns of Rails components

20. Architecture & Patterns the role of Railties

21. 👩💻 Application

22. 👩💻 Application Register hooks

23. 👩💻 Application Register hooks Load components

24. 👩💻 Application Register hooks Load components Run hooks

25. # railtie.rb initializer "initializer.name" do # do something at initialization

    end

26. # railties/lib/rails/application.rb def initializer(name, opts = {}, &block) self.class.initializer(name, opts,

    &block) end

27. # railtie.rb initializer "initializer.name" do |app| app.do_something app.config.do_something end

28. # railtie.rb initializer "initializer.name" do ActiveSupport.on_load(:active_record) do # do something

    at initialization end end

29. # activerecord/lib/active_record/railtie.rb initializer "active_record.initialize_database" do ActiveSupport.on_load(:active_record) do self.configurations = Rails.application.config.database_configuration

    establish_connection end end

30. # activerecord/lib/active_record/railtie.rb initializer "active_record.initialize_database" do ActiveSupport.on_load(:active_record) do self.configurations = Rails.application.config.database_configuration

    establish_connection end end

31. # activerecord/lib/active_record/railtie.rb initializer "active_record.initialize_database" do ActiveSupport.on_load(:active_record) do self.configurations = Rails.application.config.database_configuration

    establish_connection end end

32. # activejob/lib/active_job/railtie.rb initializer "active_job.logger" do ActiveSupport.on_load(:active_job) { self.logger = ::Rails.logger

    } end

33. # activejob/lib/active_job/railtie.rb initializer "active_model.deprecator", before: :load_environment_config do |app| app.deprecators[:active_model] =

    ActiveModel.deprecator end

34. # activejob/lib/active_job/railtie.rb initializer "active_model.deprecator", before: :load_environment_config do |app| app.deprecators[:active_model] =

    ActiveModel.deprecator end

35. • Railties are the core of the framework

36. • Railties are the core of the framework • Railties

    control load order and when hooks should be run

37. • Railties are the core of the framework • Railties

    control load order and when hooks should be run • Enables components to work together without adding dependencies

38. Architecture & Patterns Agnostic interfaces

39. if connection.is_a?(PostgresqlAdapter) # ... elsif connection.is_a?(Mysql2Adapter) # ... elsif connection.is_?(Sqlite3Adapter)

    # ... else # ... end

40. if connection.is_a?(PostgresqlAdapter) # ... elsif connection.is_a?(Mysql2Adapter) # ... elsif connection.is_?(Sqlite3Adapter)

    # ... else # ... end ❌

41. module ActiveRecord module ConnectionAdapters class AbstractAdapter # define interface end

    end end

42. module ActiveRecord module ConnectionAdapters class AbstractAdapter # define interface end

    end end module ActiveRecord module ConnectionAdapters class PostgresqlAdapter < AbstractAdapter # inherit or redefine interface end end end

43. connection.supports_foreign_keys? => true

44. class AbstractAdapter def supports_foreign_keys? false end end

45. class AbstractAdapter def supports_foreign_keys? false end end class PostgresqlAdapter <

    AbstractAdapter def supports_foreign_keys? true end end

46. # activestorage/lib/active_storage/service.rb module ActiveStorage class Service def delete(key) raise NotImplementedError

    end end end

47. # activestorage/lib/active_storage/service/gcs_service.rb class ActiveStorage class Service::GCSService < Service def delete(key)

    instrument :delete, key: key do file_for(key).delete rescue Google::Cloud::NotFoundError # Ignore files already deleted end end end end

48. @service.delete(key)

49. • Consistent interface for all supported libraries

50. • Consistent interface for all supported libraries • Simpli fi

    es Rails code to avoid using `is_a?`

51. • Consistent interface for all supported libraries • Simpli fi

    es Rails code to avoid using `is_a?` • Makes it easy for apps to swap out adapters / services

52. • Consistent interface for all supported libraries • Simpli fi

    es Rails code to avoid using `is_a?` • Makes it easy for apps to swap out adapters / services • Lowers the maintenance burden

53. Migrating Shopify's Core Rails Monolith to Trilogy Adrianna Chang Monday,

    April 24 @ 3pm

54. Architecture & Patterns Metaprogramming

55. class Post < ApplicationRecord has_many :comments end class Comment <

    ApplicationRecord belongs_to :post end

56. post = Post.first post.comments => [#<Comment:0x000000010e353838...>, #<Comment:0x000000010e3530e0>]

57. post = Post.first post.method(:comments).source_location

58. post = Post.first post.method(:comments).source_location => ["rails/activerecord/lib/ active_record/associations/builder/ association.rb", 103]

59. # activerecord/lib/active_record/associations/builder/ association.rb class ActiveRecord::Associations::Builder class Association def self.define_readers(mixin, name)

    mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1 def #{name} association(:#{name}).reader end CODE end end end

60. # activerecord/lib/active_record/associations/builder/ association.rb class ActiveRecord::Associations::Builder class Association def self.define_readers(mixin, name)

    mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1 def #{name} association(:#{name}).reader end CODE end end end

61. # activerecord/lib/active_record/associations/builder/ association.rb class ActiveRecord::Associations::Builder class Association def self.define_readers(mixin, name)

    mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1 def #{name} association(:#{name}).reader end CODE end end end

62. Post::GeneratedAssociationMethods

63. # activerecord/lib/active_record/associations/builder/ association.rb class ActiveRecord::Associations::Builder class Association def self.define_readers(mixin, name)

    mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1 def #{name} association(:#{name}).reader end CODE end end end

64. # activerecord/lib/active_record/associations/builder/ association.rb class ActiveRecord::Associations::Builder class Association def self.define_writers(mixin, name)

    mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1 def #{name}=(value) association(:#{name}).writer(value) end CODE end end end

65. # activerecord/lib/active_record/associations/builder/ association.rb class ActiveRecord::Associations::Builder class Association def self.define_writers(mixin, name)

    mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1 def #{name}=(value) association(:#{name}).writer(value) end CODE end end end

66. • Powerful tool that enables us to build beautiful, simple

    APIs

67. • Powerful tool that enables us to build beautiful, simple

    APIs • Hides complexity from your application

68. • Powerful tool that enables us to build beautiful, simple

    APIs • Hides complexity from your application • Where "Rails Magic" comes from

69. Maintaining Rails Why I work on it

70. 2010 Introduced to Rails

71. 2010 Introduced to Rails 2011 Big Nerd Ranch

72. 2010 Introduced to Rails 2011 Big Nerd Ranch 2014 1st

    conference 1st contribution

73. 2010 Introduced to Rails 2011 Big Nerd Ranch 2014 1st

    conference 1st contribution 2015 First RailsConf

74. 2010 Introduced to Rails 2011 Big Nerd Ranch 2014 1st

    conference 1st contribution 2015 First RailsConf 2017 Join Rails Core

75. 2010 Introduced to Rails 2011 Big Nerd Ranch 2014 1st

    conference 1st contribution 2015 First RailsConf 2017 Join Rails Core 2023 This RailsConf

76. I work on Rails to advance the framework

77. I work on Rails to ensure applications can stay on

    Rails

78. I work on Rails to build a stronger community

79. I work on Rails to have an impact on the

    future

80. Rails is so much more than just a framework

81. Rails is inspiring

82. Rails is empowering

83. Rails is imperfect

84. Rails is the applications we build

85. Rails is the team behind it

86. Rails is the community

87. Rails is magic

88. Thank You!