Next-generation Ruby web apps with dry-rb, rom-rb, and Roda

If you’ve ever yearned for more than the Rails way, come along and learn how a small set of tools and techniques can bring joy to your Ruby web app development, from the smallest beginnings through to the most complex of codebases. Discover how concepts like functional programming, immutability, strict typing, dependency injection and object composition can actually be easy and natural in Ruby (yes, really!), and how they will make your web app a pleasure to build, test and extend.

Transcript

1. @timriley @dry_rb @icelab @rom_rb
2. “Programmers at work maintaining a Ruby on Rails application” Eero Järnefelt, Oil on canvas, 1893 classicprogrammerpaintings.com
3. Next-generation web apps with dry-rb, rom-rb, and Roda
4. dry-rb rom-rb roda
5. Functional Ruby ➡
6. Functions as values Immutability Avoid side-effects
7. Functional objects
8. class CreateArticle def call(input) end end
9. class CreateArticle def call(input) output = some_action output end end
10. Separate data
 from behaviour
11. class CreateArticle attr_reader :repo def initialize(repo) @repo = repo end def call(input) repo.create(input) end end
12. # Initialize once create_article = CreateArticle.new(repo) # Reuse many times create_article.(title: "Hello World") create_article.(title: "Hello Singapore")
13. 14 gems,
 20 minutes,
 1 app ⏱
14. GET /articles
15. Routing & HTTP Object dependency management Views Database queries Data modelling 1 2 3 4 5
16. Routing & HTTP dry-web & roda GET /articles 1
17. > gem install dry-web-roda > dry-web-roda new blog
18. class Blog < Dry::Web::Application route do |r| r.get "articles" do r.view "articles.index" end end end
19. Object dependency management dry-component &
 dry-container GET /articles 2
20. r.view "articles.index" Blog::Container["views.articles.index"] #<Views::Article::Index> # lib/views/articles/index.rb
21. require $LOAD_PATH
22. Views dry-view GET /articles 3
23. class Index < Blog::View configure do |config| config.template = "articles/index" end def locals(options = {}) {} end end
24. Object dependency management dry-auto_inject GET /articles 2
25. class Index < Blog::View configure do |config| config.template = "articles/index" end def locals(options = {}) {} end end
26. class Index < Blog::View configure do |config| config.template = "articles/index" end include Blog::Import["blog.repositories.articles"] def locals(options = {}) super.merge(articles: articles.listing) end end
27. Database queries rom &
 rom-repository GET /articles 4
28. Define a boundary
29. module Articles class Repository < ROM::Repository[:articles] def listing articles.published.to_a end end end
30. Database queries rom-sql GET /articles 4
31. module Relations class Articles < ROM::Relation[:sql] def published where(published: true) end end end
32. module Articles class Repository < ROM::Repository[:articles] def listing articles.published.to_a end end end
33. module Articles class Repository < ROM::Repository[:articles] def listing articles.published.as(Article).to_a end end end
34. Data modelling dry-types GET /articles 5
35. class Article < Dry::Types::Struct attribute :title, Types::Strict::String attribute :body, Types::Strict::String attribute :published_at, Types::Strict::Time end
36. class Index < Blog::View configure do |config| config.template = "articles/index" end include Blog::Import["blog.repositories.articles"] def locals(options = {}) super.merge(articles: articles.listing) end end
37. ol - articles.each do |article| li = article.title Blog::Container["views.articles.index"].() <ol> <li>Hello Singapore</li> <li>Hello World</li> </ol>
38. class Blog < Dry::Web::Application route do |r| r.get "articles" do r.view "articles.index" end end end
39. GET /articles
40. Routing & HTTP dry-web & roda Object dependency management dry-component, -container & -auto_inject Views dry-view Database queries rom, rom-sql & rom-repository Data modelling dry-types 1 2 3 4 5
41. POST /articles
42. Validation Database commands Success & error handling 1 2 3
43. class MyApp < Dry::Web::Application route do |r| r.post "articles" do r.resolve "operations.create_article" do |create| create.(r[:article]) end end end end
44. r.resolve "operations.create_article" Blog::Container["operations.create_article"] #<Operations::CreateArticle> # lib/operations/create_article.rb
45. class CreateArticle def call(input) result = Validation::ArticleSchema.(input) end end
46. Validation dry-validation POST /articles 1
47. module Validation ArticleSchema = Dry::Validation.Form do required(:title).filled(min_size?: 3) required(:body).filled required(:published).filled(:bool?) required(:published_at).filled(:time?) end end
48. input = { "published" => "1", "published_at" => "2016-05-24 16:30" } ArticleSchema.(input).to_h { published: true, published_at: 2016-05-24 16:30:00 +1000 }
49. ArticleSchema.("published" => "1").messages { :title => [ "is missing", "size cannot be less than 5"], :body => ["is missing"], :published_at => ["is missing"] }
50. class CreateArticle include Blog::Import["repositories.articles"] def call(input) result = Validation::ArticleSchema.(input) if result.success? articles.create(result) end end end
51. class CreateArticle include Blog::Import["repositories.articles"] def call(input) result = Validation::ArticleSchema.(input) if result.success? articles.create(result) end end end
52. Database commands rom, rom-repository POST /articles 2
53. module Relations class Articles < ROM::Relation[:sql] schema(:articles) do attribute :id, Types::Serial attribute :title, Types::String attribute :body, Types::String attribute :published, Types::Bool attribute :published_at, Types::Time end end end
54. module Articles class Repository < ROM::Repository[:articles] commands :create end end
55. def call(input) result = Validation::ArticleSchema.(input) if result.success? attrs = articles.create(validation) Article.new(attrs) end end
56. Success & failure handling dry-monads &
 dry-result_matcher POST /articles 3
57. include Dry::Monads::Either::Mixin include Dry::ResultMatcher.for(:call) def call(input) validation = Validation::ArticleSchema.(input) if validation.success? result = articles.create(validation) Right(Article.new(result)) else Left(validation) end end
58. r.post do r.resolve "operations.create_article" do |create| create.(r[:article]) do |m| m.success do r.redirect "/articles" end m.failure do |validation| r.view "articles.new", validation: validation end end end end
59. r.post do r.resolve "operations.create_article" do |create| create.(r[:article]) do |m| m.success do r.redirect "/articles" end m.failure do |validation| r.view "articles.new", validation: validation end end end end
60. POST /articles
61. Validation dry-validation Database commands rom, rom-sql, rom-repository Success & error handling dry-monads & dry-result_matcher 1 2 3
62. Change
63. New article form
 for admins
64. Isolated testing
65. Fast testing!
66. Email articles to subscribers
67. c llbacks
68. dry-transaction
69. Blog::Transactions.define do |t| t.define "transactions.create_article" do step :create, with: "operations.create_article" step :notify, with: "operations.notify_subscribers" end end
70. Blog::Transactions.define do |t| t.define "transactions.create_article" do step :create, with: "operations.create_article" step :notify, with: "operations.notify_subscribers" end end
71. Blog::Transactions.define do |t| t.define "transactions.create_article" do step :create, with: "operations.create_article" step :notify, with: "operations.notify_subscribers" end end
72. create_article.(r[:article]) do |m| m.success do r.redirect "/articles" end m.failure :create do |errors| r.view "articles.new", validation: errors end m.failure :notify do |error| # ... end end
73. Founded on simplicity
74. Small components, single focus Easy to understand, reuse, test
75. Designed for
 the domain
76. A change-positive architecture
77. A change-positive app is maintainable
78. A change-positive app is sustainable
79. A change-positive app is joyful
80. An investment
 in Ruby
81. Jeremy Evans and many more! ❤ Andy Holland Piotr Solnica
82. hanami trailblazer
83. bit.ly / dry-rdrc