A New Ruby Toolbox

dry-rb and rom-rb are libraries for Rubyists who are looking for a different set of tools for web app development. Let’s take a walk through how to build an app with these families of gems, and look at some lessons I’ve learnt during my own dry-rb/rom-rb journey.

Transcript

1. A new Ruby toolbox
2. @jojoconstance Icelab
3. !
5. dry-rb rom-rb
6. Functional, object oriented Ruby
8. Let’s learn
9. • Get data and show it • Take data and save it
10. GET request
11. Routes GET /products 1
12. route "products" do |r| r.get do r.view “products.index” end end
13. route "products" do |r| r.get do r.view “products.index” end end
14. route "products" do |r| r.get do r.view "products.index" end end
15. Routes GET /products 1 gem "dry-web-roda"
16. require "dry-web-roda" class App < Dry::Web::Roda::Application route "products" do |r| r.get do r.view "products.index" end end end
17. Views GET /products 2
18. route "products" do |r| r.get do r.view "products.index" end end
19. Views GET /products 2 gem "dry-view"
20. class Index < Dry::View::Controller configure do |config| config.paths = [File.join(__dir__, "templates")] config.layout = "app" config.template = "index" end expose :products end
21. class Index < Dry::View::Controller configure do |config| config.paths = [File.join(__dir__, "templates")] config.layout = "app" config.template = "index" end expose :products end
22. class Index < Dry::View::Controller configure do |config| config.paths = [File.join(__dir__, "templates")] config.layout = "app" config.template = "index" end expose :products end
23. class Index < Dry::View::Controller configure do |config| config.paths = [File.join(__dir__, "templates")] config.layout = "app" config.template = "index" end expose :products end
24. class Index < Dry::View::Controller configure do |config| config.paths = [File.join(__dir__, "templates")] config.layout = "app" config.template = "index" end expose :products end
25. class Index < Dry::View::Controller configure do |config| config.paths = [File.join(__dir__, "templates")] config.layout = "app" config.template = "index" end expose :products end
26. module App class ViewController < Dry::View::Controller configure do |config| config.paths = [File.join(__dir__, "templates")] config.layout = "app" end end end
27. module App class ViewController < Dry::View::Controller configure do |config| config.paths = [File.join(__dir__, "templates")] config.layout = "app" end end end
28. class Index < App::ViewController configure do |config| config.template = "index" end expose :products end
29. class Index < App::ViewController configure do |config| config.template = "index" end expose :products end
30. Views GET /products 2 exposures
31. class Index < App::ViewController configure do |config| config.template = "index" end expose :products end
32. Views GET /products 2 gem "dry-system"
33. App::Container
34. include App::Import["product_repo"]
35. class Index < App::ViewController include App::Import["product_repo"] expose :products do product_repo.listing end end
36. class Index < App::ViewController include App::Import["product_repo"] expose :products do product_repo.listing end end
38. include App::Import["product_repo"] # product_repo becomes available!
39. Persistence GET /products 3 gem "rom-repository"
40. class ProductRepo < App::Repository[:products] def listing(limit: 10) products .order_by_created_at .limit(limit) end end
41. class ProductRepo < App::Repository[:products] def listing(limit: 10) products .order_by_created_at .limit(limit) end end
42. class ProductRepo < App::Repository[:products] def listing(limit: 10) products .order_by_created_at .limit(limit) end end
43. Database GET /products 4 gem "rom-sql"
44. class Products < ROM::Relation[:sql] schema :products, infer: true def order_by_created_at order(self[:created_at].desc) end end
45. class Products < ROM::Relation[:sql] schema :products, infer: true def order_by_created_at order(self[:created_at].desc) end end
46. class Products < ROM::Relation[:sql] schema :products, infer: true def order_by_created_at order(self[:created_at].desc) end end
47. Let’s recap
48. Small gems, small objects
49. dry-web-roda dry-system dry-view
50. rom-repository rom-sql
51. POST request
52. Routes POST /products 1
53. route "products" do |r| r.post do r.resolve "products.create" do |create| create.(r[:product]) do |m| m.success do r.redirect "/success" end m.failure do |result| r.view "error", error: result end end end end end
54. route "products" do |r| r.post do r.resolve "products.create" do |create| create.(r[:product]) do |m| m.success do r.redirect "/success" end m.failure do |result| r.view "error", error: result end end end end end
55. route "products" do |r| r.post do r.resolve "products.create" do |create| create.(r[:product]) do |m| m.success do r.redirect "/success" end m.failure do |result| r.view "error", error: result end end end end end
56. Routes POST /products 1 .() alias .call()
57. route "products" do |r| r.post do r.resolve "products.create" do |create| create.(r[:product]) do |m| m.success do r.redirect "/success" end m.failure do |result| r.view "error", error: result end end end end end
58. route "products" do |r| r.post do r.resolve "products.create" do |create| create.(r[:product]) do |m| m.success do r.redirect "/success" end m.failure do |result| r.view "error", error: result end end end end end
59. route "products" do |r| r.post do r.resolve "products.create" do |create| create.(r[:product]) do |m| m.success do r.redirect "/success" end m.failure do |result| r.view "error", error: result end end end end end
60. Operations POST /products 2 .() alias .call()
61. Surprise!
62. Monads
63. Result matching POST /products 3 gem "dry-matcher"
 gem "dry-monads"
65. class Create < App::Operation include App::Import["product_repo"] def call(input) product = product_repo.create(input) Right(product) end end
66. class Create < App::Operation include App::Import["product_repo"] def call(input) product = product_repo.create(input) Right(product) end end
67. class Create < App::Operation include App::Import["product_repo"] def call(input) product = product_repo.create(input) Right(product) end end
68. class Create < App::Operation include App::Import["product_repo"] def call(input) product = product_repo.create(input) Right(product) end end
69. class Create < App::Operation include App::Import["product_repo"] def call(input) product = product_repo.create(input) Right(product) end end
70. class Create < App::Operation include App::Import["product_repo"] def call(input) if valid? product = product_repo.create(input) Right(product) else Left("Invalid input”) end end end
71. route "products" do |r| r.post do r.resolve "products.create" do |create| create.(r[:product]) do |m| m.success do r.redirect "/success" end m.failure do |result| r.view "error", error: result end end end end end
72. Validation POST /products 4 gem "dry-validation"
73. schema = Dry::Validation.Form do required(:title).filled(:str?)
 required(:published_at).filled(:date?) required(:stock_level).maybe(:int?, gt?: 1) end
74. schema = Dry::Validation.Form do required(:title).filled(:str?)
 required(:published_at).filled(:date?) required(:stock_level).maybe(:int?, gt?: 1) end
75. schema = Dry::Validation.Form do required(:title).filled(:str?)
 required(:published_at).filled(:date?) required(:stock_level).maybe(:int?, gt?: 1) end
76. result = schema.( 'title' => 'A Lion in the Meadow’, 'published_at' => '1995-05-25', 'stock_level' => '' ) puts result.to_h { :title=>"A Lion in the Meadow", :published_at=>#<Date: 1995-05-25>, :stock_level=>nil }
77. result = schema.( 'title' => 'A Lion in the Meadow’, 'published_at' => '1995-05-25', 'stock_level' => '' ) puts result.to_h { :title=>"A Lion in the Meadow", :published_at=>#<Date: 1995-05-25>, :stock_level=>nil }
78. result = schema.( 'title' => '', 'published_at' => '', 'stock_level' => '0' ) puts result.errors { :title=>["must be filled"], :published_at=>["must be filled"], :stock_level=>["must be greater than 1"] }
79. result = schema.( 'title' => '', 'published_at' => '', 'stock_level' => '0' ) puts result.errors { :title=>["must be filled"], :published_at=>["must be filled"], :stock_level=>["must be greater than 1"] }
80. class Create < App::Operation include App::Import["product_repo"] def call(input) validation = schema.(input) if validation.success? product = product_repo.create(validation.to_h) Right(product) else Left(validation) end end end
81. class Create < App::Operation include App::Import["product_repo"] def call(input) validation = schema.(input) if validation.success? product = product_repo.create(validation.to_h) Right(product) else Left(validation) end end end
82. class Create < App::Operation include App::Import["product_repo"] def call(input) validation = schema.(input) if validation.success? product = product_repo.create(input) Right(product) else Left(validation) end end end
83. Commands POST /products 5
84. class Products < App::Repository[:products] commands :create, update: :by_pk, delete: :by_pk 
 def listing(limit: 10) # … end end
85. class Products < App::Repository[:products] commands :create, update: :by_pk, delete: :by_pk 
 def listing(limit: 10) # … end end
86. products_repo.create( title: "Where the Wild Things Are", published_at: #<Date: 1963-04-09>, stock_level: 4 )
 => #<ROM::Struct[Product] id=1 title="Where the Wild Things Are" published_at=#<Date: 1963-04-09> stock_level=4>
87. products_repo.create( title: "Where the Wild Things Are", published_at: #<Date: 1963-04-09>, stock_level: 4 )
 => #<ROM::Struct[Product] id=1 title="Where the Wild Things Are" published_at=#<Date: 1963-04-09> stock_level=4>
88. products_repo.update( product.id, title: "Wild Things" ) => #<ROM::Struct[Product] id=1 name="Wild Things" published_at=#<Date: 1963-04-09> stock_level=4> products_repo.delete(product.id)
89. products_repo.update( product.id, title: "Wild Things" ) => #<ROM::Struct[Product] id=1 name="Wild Things" published_at=#<Date: 1963-04-09> stock_level=4> products_repo.delete(product.id)
90. products_repo.update( product.id, title: "Wild Things" ) => #<ROM::Struct[Product] id=1 name="Wild Things" published_at=#<Date: 1963-04-09> stock_level=4> products_repo.delete(product.id)
91. Let’s recap
92. Operations do one thing
93. dry-matcher dry-monads dry-validation
94. CRUD is easy
95. &
96. &
97. What does it make possible?
98. .() everywhere
99. Request -> f(x) -> f(x) -> Response
100. Objects as functions
101. Separate data from behaviour
102. dry-transaction
103. App::Transactions.define do |t| t.define "transactions.create_product" do step :create, with: "products.operations.create" enqueue :index, with: "search.operations.index_product" enqueue :notify, with: "products.operations.notify" end end
104. App::Transactions.define do |t| t.define "transactions.create_product" do step :create, with: "products.operations.create" enqueue :index, with: "search.operations.index_product" enqueue :notify, with: "products.operations.notify" end end
105. App::Transactions.define do |t| t.define "transactions.create_product" do step :create, with: "products.operations.create" enqueue :index, with: "search.operations.index_product" enqueue :notify, with: "products.operations.notify" end end
106. App::Transactions.define do |t| t.define "transactions.create_product" do step :create, with: "products.operations.create" enqueue :index, with: "search.operations.index_product" enqueue :notify, with: "products.operations.notify" end end
107. FP FTW!
108. Makes you think
109. Views deserve good design too!
110. A good template is a simple one
111. Love your database ❤
112. app != database
113. Good decisions in both places
115. Good decisions give us confidence )
116. Good decisions give us power *
117. HA HA! BUSINESS!
118. Want to try it out?
119. > gem install dry-web-roda > dry-web-roda new your_app
120. Thank you! @jojoconstance dry-rb/dry-web-blog More resources at:
 http://josephinehall.github.io/