Real-world Functional Ruby

RubyConf Malaysia 2017

Transcript

1. Real-world Functional Ruby RubyConf Malaysia 2017
2. @timriley
4. @icelab
5. !
7. @dry_rb @rom_rb
10. “Programmers at work maintaining a Ruby on Rails application” Eero Järnefelt 
 Oil on canvas, 1893
13. user.rb after_save accepts_nested_attributes_for
14. ⏱ DESIGN STAMINA HYPOTHESIS
15. ⏱ DESIGN STAMINA HYPOTHESIS
16. ⏱ DESIGN STAMINA HYPOTHESIS
17. ⏱ DESIGN STAMINA HYPOTHESIS No design
18. ⏱ DESIGN STAMINA HYPOTHESIS No design
19. ⏱ DESIGN STAMINA HYPOTHESIS No design
20. ⏱ DESIGN STAMINA HYPOTHESIS No design Good design
21. ⏱ DESIGN STAMINA HYPOTHESIS No design Good design
22. ⏱ DESIGN STAMINA HYPOTHESIS No design Good design Design payoff line
23. Object-oriented design
24. The gap.
27. Haskell
28. Haskell
29. Haskell
30. Real-world Functional Ruby RubyConf Malaysia 2017 Tim Riley // @timriley
31. Functional Ruby, can!
32. Functional Ruby, can!
33. FP is hot AF
35. App as series of transformations
36. Request → [*] → [*] → Response
37. App as series of transformations
38. App as series of functions
39. Functional objects
40. class ImportProducts def call(feed) import_from(feed) end end
41. class ImportProducts def call(feed) import_from(feed) end end
42. class ImportProducts def call(feed) import_from(feed) end end
43. class ImportProducts def call(feed) import_from(feed) end end
44. Separate data from behaviour
45. Immutable
46. class ImportProducts def call(feed) end end records = download_feed.(feed) records.each do |attrs| products_repo.create(attrs) end
47. class ImportProducts def call(feed) records = download_feed.(feed) records.each do |attrs| products_repo.create(attrs) end end end
48. class ImportProducts def call(feed) records = download_feed.(feed) records.each do |attrs| product_repo.create(attrs) end end end
49. download_feed: product_repo:
50. class ImportProducts attr_reader :download_feed attr_reader :products_repo def initialize(download_feed:, product_repo:) @download_feed = download_feed @products_repo = products_repo end def call(feed) # ... end end
51. class ImportProducts attr_reader :download_feed attr_reader :product_repo def initialize(download_feed:, product_repo:) @download_feed = download_feed @product_repo = product_repo end def call(feed) # ... end end
52. # Initialize once import = ImportProducts.new( download_feed: download, product_repo: repo, ) # Reuse many times import.(:books_feed) import.(:dvds_feed)
53. # Initialize once import = ImportProducts.new( download_feed: download, product_repo: repo, ) # Call many times import.(book_feed) import.(film_feed)
54. Feeds::Create Feeds::Update Feeds::Delete Products::Update
55. Behaviour
56. Data
57. Types
58. Values
59. class Product attr_reader :title, :isbn def initialize(**attrs) @title = attrs[:title] @isbn = attrs[:isbn] end def slug "#{to_slug(title)}-#{isbn}" end end
60. class Product attr_reader :title, :isbn def initialize(**attrs) @title = attrs[:title] @isbn = attrs[:isbn] end def slug "#{to_slug(title)}-#{isbn}" end end
61. Values objects are first-class
62. Values & Functions
63. Values Functions Hold data Operate on data
64. Values Functions Hold data Operate on data
65. Values Functions Hold data Operate on data Inert Active
66. Values Functions Hold data Operate on data Inert Active Content Pipeline
67. Functional design
68. Functional, object-oriented design
69. Functional Ruby yields better
 object-oriented Ruby!
70. RSpec.describe ImportProducts
71. download_feed product_repo
72. let(:download) { double(:download) } let(:repo) { double(:repo) }
73. subject(:import) { ImportProducts.new( download_feed: download, product_repo: repo, ) }
74. let(:feed) { Feed.new(…) } before do allow(download_feed) .to receive(:call) .with(feed) .and_return(books_data) end
75. let(:feed) { Feed.new(…) } before do allow(download) .to receive(:call) .with(feed) .and_return(BOOKS_DATA) end
76. it "creates the products" do expect(repo) .to receive(:create).with(title: "…") import.(feed) end
77. Import
 Products download_feed product_repo
78. Dependencies
79. App as graph
82. Good design makes change easier
83. Functional design makes change easier
84. Real developers hate him! He’s idealistic He’s making too many .rb files He found a #method to build better apps. Learn the one WEIRD trick to his stunning results! GET FUNCTIONAL NOW
86. A real-world functional Ruby ecosystem
87. dry-rb
89. Dependency management
90. dry-system & dry-auto_inject
91. # lib/my_app/import_products.rb MyApp::Container[“import_products"] #<MyApp::ImportProducts>
92. # lib/my_app/import_products.rb MyApp::Container["import_products"] #<MyApp::ImportProducts>
93. class ImportProducts include MyApp::Import[ "products.download_feed", "product_repo", ] def call(feed) # ... end end
94. # lib/my_app/import_products.rb MyApp::Container["import_products"] #<MyApp::ImportProducts>
95. # lib/my_app/import_products.rb MyApp::Container["import_products"] #<MyApp::ImportProducts download_feed=#<DownloadFeed> product_repo=#<ProductRepo>>
96. ImportProducts.new( download_feed: double(:download) ) #<ImportProducts download_feed=#<Double :download> product_repo=#<ProductRepo>>
97. ImportProducts.new( download_feed: double(:download) ) #<ImportProducts download_feed=#<Double :download> product_repo=#<ProductRepo>>
98. Result handling
99. dry-monads & dry-matcher
100. # Successful result Right(imported_products) # Failed result Left(error)
101. import_products.() do |m| m.success do |imported_products| # … end m.failure do |error| # … end end
102. Data & types
103. dry-validation
104. Dry::Validation.Schema do required(:name).filled required(:url).filled(format?: /…/) required(:active).filled(:bool?) end
105. dry-types & dry-struct
106. ISBN = Strict::String .constrained(format: /…/)
107. class Product < Dry::Struct attribute :title, Types::Strict::String attribute :isbn, Types::ISBN end
108. View rendering
109. dry-view
110. expose :product do |slug:| product_repo.by_slug(slug) end
111. HTTP & routing
112. dry-web-roda
113. $ dry-web-roda new my_app
114. . ├── Gemfile ├── README.md ├── Rakefile ├── apps │ └── main │ ├── lib │ │ └── main │ │ └── views │ │ └── welcome.rb │ ├── system │ │ ├── boot │ │ │ └── view.rb │ │ ├── boot.rb │ │ └── main │ │ ├── application.rb │ │ ├── container.rb │ │ ├── import.rb │ │ ├── transactions.rb │ │ ├── view_context.rb │ │ └── view_controller.rb
115. │ │ └── relations │ └── types.rb ├── log ├── spec │ ├── app_helper.rb │ ├── db_helper.rb │ ├── spec_helper.rb │ └── support │ ├── db │ │ └── test_factories.rb │ └── test_helpers.rb └── system ├── blog │ ├── application.rb │ ├── container.rb │ ├── import.rb │ └── settings.rb ├── boot │ └── rom.rb └── boot.rb 28 directories, 37 files
116. Persistence
117. rom-rb
118. Dependency management Result handling Data validation & types Views Routing & HTTP Database persistence
120. A functional Ruby movement
123. hanami
124. RailsClub 2017 // @jodosha Functional Web with Hanami
125. Ruby is ready
126. There is nothing more powerful than an idea whose time has come. — Victor Hugo
127. Bridging the gap for Ruby
128. Real-world Functional Ruby
129. FP + OO = Win!
130. FP + OO + Community = Win!
131. Functional Ruby is supported
132. Functional Ruby is practical
133. Functional Ruby is worth a try!
134. dry-rb/dry-web-blog
135. Thank you! @timriley dry-rb/dry-web-blog bit.ly/rubyconfmy-fp-ruby