Real-world functional Ruby

Transcript

1. Real-world Functional Ruby Southeast Ruby 2017
2. @timriley
4. @icelab
5. !
7. @dry_rb @rom_rb
10. PODCASTERS
11. “TBA”
14. “Programmers at work maintaining a Ruby on Rails application” Eero Järnefelt 
 Oil on canvas, 1893
17. user.rb after_save accepts_nested_attributes_for
18. ⏱ DESIGN STAMINA HYPOTHESIS
19. ⏱ DESIGN STAMINA HYPOTHESIS
20. ⏱ DESIGN STAMINA HYPOTHESIS
21. ⏱ DESIGN STAMINA HYPOTHESIS No design
22. ⏱ DESIGN STAMINA HYPOTHESIS No design
23. ⏱ DESIGN STAMINA HYPOTHESIS No design
24. ⏱ DESIGN STAMINA HYPOTHESIS No design Good design
25. ⏱ DESIGN STAMINA HYPOTHESIS No design Good design
26. ⏱ DESIGN STAMINA HYPOTHESIS No design Good design Design payoff line
27. Object-oriented design
28. The gap.
31. Haskell
32. Haskell
33. Haskell
34. Real-world Functional Ruby Southeast Ruby 2017 Tim Riley // @timriley
35. FP is hot AF
37. App as series of transformations
38. Request → [*] → [*] → Response
39. App as series of transformations
40. App as series of functions
41. Functional objects
42. class ImportProducts def call(feed) import_from(feed) end end
43. class ImportProducts def call(feed) import_from(feed) end end
44. class ImportProducts def call(feed) import_from(feed) end end
45. class ImportProducts def call(feed) import_from(feed) end end
46. Separate data from behaviour
47. Immutable
48. class ImportProducts def call(feed) end end records = download_feed.(feed) records.each do |attrs| products_repo.create(attrs) end
49. class ImportProducts def call(feed) records = download_feed.(feed) records.each do |attrs| products_repo.create(attrs) end end end
50. class ImportProducts def call(feed) records = download_feed.(feed) records.each do |attrs| product_repo.create(attrs) end end end
51. download_feed: product_repo:
52. 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
53. 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
54. # Initialize once import = ImportProducts.new( download_feed: download, product_repo: repo, ) # Reuse many times import.(:books_feed) import.(:dvds_feed)
55. # Initialize once import = ImportProducts.new( download_feed: download, product_repo: repo, ) # Call many times import.(book_feed) import.(film_feed)
56. Feeds::Create Feeds::Update Feeds::Delete Products::Update
57. Behaviour
58. Data
59. Types
60. Values
61. class Product attr_reader :title, :isbn def initialize(**attrs) @title = attrs[:title] @isbn = attrs[:isbn] end def slug "#{to_slug(title)}-#{isbn}" end end
62. class Product attr_reader :title, :isbn def initialize(**attrs) @title = attrs[:title] @isbn = attrs[:isbn] end def slug "#{to_slug(title)}-#{isbn}" end end
63. Values objects are first-class
64. Values & Functions
65. Values Functions Hold data Operate on data
66. Values Functions Hold data Operate on data
67. Values Functions Hold data Operate on data Inert Active
68. Values Functions Hold data Operate on data Inert Active Content Pipeline
69. Functional design
70. Functional, object-oriented design
71. Functional Ruby yields better
 object-oriented Ruby!
72. RSpec.describe ImportProducts
73. download_feed product_repo
74. let(:download) { double(:download) } let(:repo) { double(:repo) }
75. subject(:import) { ImportProducts.new( download_feed: download, product_repo: repo, ) }
76. let(:feed) { Feed.new(…) } before do allow(download_feed) .to receive(:call) .with(feed) .and_return(books_data) end
77. let(:feed) { Feed.new(…) } before do allow(download) .to receive(:call) .with(feed) .and_return(BOOKS_DATA) end
78. it "creates the products" do expect(repo) .to receive(:create).with(title: "…") import.(feed) end
79. Import
 Products download_feed product_repo
80. Dependencies
81. App as graph
84. Good design makes change easier
85. Functional design makes change easier
86. 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
88. A real-world functional Ruby ecosystem
89. dry-rb
92. Dependency management
93. dry-system & dry-auto_inject
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>
96. class ImportProducts include MyApp::Import[ "products.download_feed", "product_repo", ] def call(feed) # ... end end
97. # lib/my_app/import_products.rb MyApp::Container["import_products"] #<MyApp::ImportProducts>
98. # lib/my_app/import_products.rb MyApp::Container["import_products"] #<MyApp::ImportProducts download_feed=#<DownloadFeed> product_repo=#<ProductRepo>>
99. ImportProducts.new( download_feed: double(:download) ) #<ImportProducts download_feed=#<Double :download> product_repo=#<ProductRepo>>
100. ImportProducts.new( download_feed: double(:download) ) #<ImportProducts download_feed=#<Double :download> product_repo=#<ProductRepo>>
101. Result handling
102. dry-monads & dry-matcher
103. # age, or nil Maybe(age) # successful import results Right(imported_products)
104. # age, or nil Maybe(age) Maybe(33) => Some(33) # successful import results Right(imported_products)
105. # age, or nil Maybe(age) Maybe(33) => Some(33) Maybe(nil) => None
106. # Successful import result Right(imported_products)
107. import_products.() do |m| m.success do |imported_products| # … end m.failure do |error| # … end end
108. Data & types
109. dry-validation
110. Dry::Validation.Schema do required(:name).filled required(:url).filled(format?: /…/) required(:active).filled(:bool?) end
111. dry-types & dry-struct
112. ISBN = Strict::String .constrained(format: /…/)
113. class Product < Dry::Struct attribute :title, Types::Strict::String attribute :isbn, Types::ISBN end
114. View rendering
115. dry-view
116. expose :product do |slug:| product_repo.by_slug(slug) end
117. HTTP & routing
118. dry-web-roda
119. $ dry-web-roda new my_app
120. . ├── 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
121. │ │ └── 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
122. Persistence
123. rom-rb
124. Dependency management Result handling Data validation & types Views Routing & HTTP Database persistence
126. A functional Ruby movement
129. hanami
130. RailsClub 2017 // @jodosha Functional Web with Hanami
131. Ruby is ready
132. There is nothing more powerful than an idea whose time has come. — Victor Hugo
133. Bridging the gap for Ruby
134. Real-world Functional Ruby
135. FP + OO = Win!
136. FP + OO + Community = Win!
137. Functional Ruby is supported
138. Functional Ruby is practical
139. Functional Ruby is worth a try!
140. dry-rb/dry-web-blog
141. Thank you! @timriley dry-rb/dry-web-blog bit.ly/se-functional-ruby