Poderosas Interfaces Rails

Esta palestra aborda boas práticas na modelagem de aplicações Rails. São apresentadas algumas técnicas que auxiliam na criação de componentes de baixo acoplamento, facilitando o desenvolvimento e manutenção destes componentes, diminuindo o tempo de execução de seus testes unitários e proporcionando uma experiência mais prazerosa no desenvolvimento de aplicações complexas utilizando Ruby e Rails.

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1. Poderosas Interfaces Rails Caike Souza RubyConf BR 2012
2. @caike
7. Problemas http://www.flickr.com/photos/lianneviau/499003712/sizes/l/in/photostream/
8. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end
9. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end Client
10. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end Client Interface
11. Interface
12. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end Client
13. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end
14. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end
15. Protocolo
16. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end
17. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment,success: 'You are now subscribed!') else render :index end end end
18. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment,success: 'You are now subscribed!') else render :index end end end Baixa Granularidade
19. Granularidade
20. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment,success: 'You are now subscribed!') else render :index end end end
21. Callbacks & Observers if pra if ca if ralho e outras bizarrices
22. As Três Leis das Interfaces
23. Os Três Filtros de Interfaces
24. fazer aquilo que seus métodos indicam fazer. #1
25. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end
26. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end
27. Payment#save vs. Payment#place
28. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end
29. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.place redirect_to(payment, success:'You are now subscribed!') else render :index end end end
30. class Payment < ActiveRecord::Base protected :save ## # Add your comments here. # Really. ## def place end end
31. deve ser eficiente. #2
32. <h2>Usuários Registrados</h2> <div class="users"> <ul> <% User.recent.paginate(@page).each do |user| %> <li><%= link_to(user.full_name, user) %></li> <% end %> </ul> </div>
33. <h2>Registered Users</h2> <div class="users"> <ul> <% User.recent.paginate(@page).each do |user| %> <li><%= link_to(user.full_name, user) %></li> <% end %> </ul> </div>
34. <h2>Registered Users</h2> <div class="users"> <ul> <% @users.each do |user| %> <li><%= link_to(user.full_name, user) %></li> <% end %> </ul> </div>
35. <h2>Usuários Registrados</h2> <div class="users"> <ul> <% @users.each do |user| %> <li><%= link_to(user.full_name, user) %></li> <% end %> </ul> </div>
36. avisar ao client caso haja algum erro. #3
37. raise "Invalid HTTP request"
38. raise "Invalid HTTP request"
39. raise "Invalid HTTP request" vs. raise "Erro na autorização do Cartão de Crédito"
40. raise "Erro na autorização do Cartão de Crédito"
41. raise "Erro na autorização do Cartão de Crédito"
42. fazer aquilo que seus métodos indicam fazer. #1
43. deve ser eficiente. #2
44. avisar ao client caso haja algum erro. #3
45. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment, success:'You are now subscribed!') else render :index end end end
46. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.save redirect_to(payment,success: 'You are now subscribed!') else render :index end end end
47. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.place redirect_to(payment,success: 'You are now subscribed!') else render :index end end end
48. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.place redirect_to(payment,success: 'You are now subscribed!') else render :index end end end fazendo muita coisa
49. Factory Method
50. class PaymentsController < ApplicationController def create payment = Payment.new(params[:payment]) if payment.place redirect_to(payment,success: 'You are now subscribed!') else render :index end end end
51. class PaymentsController < ApplicationController def create payment = Payment.build_with(params[:payment]) if payment.place redirect_to(payment,success: 'You are now subscribed!') else render :index end end end
52. class PaymentsController < ApplicationController def create payment = Payment.build_with(params[:payment]) if payment.place redirect_to(payment, success:'You are now subscribed!') else render :index end end end
53. class PaymentsController < ApplicationController def create payment = Payment.build_with(params[:payment]) if payment.place redirect_to(payment, success:'You are now subscribed!') else render :index end end end
54. class PaymentsController < ApplicationController def create payment = Payment.build_with(params[:payment]) if payment.place redirect_to(payment, success:'You are now subscribed!') else render :index end end end
55. class PlanSubscriber def self.build_for(user) end def subscribe(payment_info) end end
56. class PlanSubscriber def self.build_for(user) end def subscribe(payment_info) end end
57. require 'plan_subscriber' describe PlanSubscriber do end
58. class PaymentsController < ApplicationController def create payment = Payment.build_with(params[:payment]) if payment.place redirect_to(payment, success:'You are now subscribed!') else render :index end end end
59. class PaymentsController < ApplicationController def create payment = Payment.build_with(params[:payment]) if payment.place redirect_to(payment, success:'You are now subscribed!') else render :index end end end
60. class PaymentsController < ApplicationController def create plan_subscriber = PlanSubscriber.build_for(current_user) if plan_subscriber.subscribe(params[:payment]) payment = plan_subscriber.payment redirect_to(payment, success:'You are now subscribed!') else render :index end end end
61. Models != AR::Base
62. Rails não é o seu domain http://blog.firsthand.ca/2011/10/rails-is-not-your- application.html
64. Design by Contract
65. Pre-Conditions Post-Conditions Invariants
66. Pre-Conditions
67. E-mail deve ser válido. Produto deve estar disponível.
68. Pre-Conditions Post-Conditions
69. Assento deve estar reservado. Novo pagamento deve ser criado.
70. class PaymentsController < ApplicationController def create plan_subscriber = PlanSubscriber.build_for(current_user) if plan_subscriber.subscribe(params[:payment]) payment = plan_subscriber.payment redirect_to(payment, success:'You are now subscribed!') else render :index end end end
71. Pre-Conditions Post-Conditions Invariants
72. Usuário deve estar ativado. Loja deve estar aberta.
73. Pre-Conditions Post-Conditions Invariants
75. Pirâmide de complexidade de models
76. 0 1 2 Pirâmide de complexidade de models
77. 0 Rails out-of-the-box 1 2 Pirâmide de complexidade de models
78. 0 Rails out-of-the-box 1 Não utilizar métodos AR::Base nos controllers 2 Pirâmide de complexidade de models
79. 0 2 Rails out-of-the-box Não utilizar classes AR::Base nos controllers 1 Não utilizar métodos AR::Base nos controllers Pirâmide de complexidade de models
81. "Bons sistemas orientados a objeto focam em como as suas diferentes partes se comunicam, e não nas propriedades internas e comportamento dessas partes." Alan Kay
82. Mensagens
83. Mensagens
84. Protocolo
85. Os Três Filtros de Interfaces
86. Design by Contract
87. Obrigado :)
88. Poderosas Interfaces Rails Caike Souza RubyConf BR 2012