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.

Transcript

1. Poderosas Interfaces
   Rails
   Caike Souza
   RubyConf BR 2012
   

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2. @caike
   

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7. Problemas
   http://www.flickr.com/photos/lianneviau/499003712/sizes/l/in/photostream/
   

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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
   

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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
   

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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
    

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11. Interface
    

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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
    

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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
    

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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
    

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15. Protocolo
    

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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
    

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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
    

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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
    

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19. Granularidade
    

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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
    

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21. Callbacks
    &
    Observers
    if pra
    if ca
    if ralho
    e outras bizarrices
    

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22. As Três Leis das
    Interfaces
    

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23. Os Três Filtros de
    Interfaces
    

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24. fazer aquilo que
    seus métodos
    indicam fazer.
    #1
    

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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
    

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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
    

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27. Payment#save
    vs.
    Payment#place
    

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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
    

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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
    

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30. class Payment < ActiveRecord::Base
    protected :save
    ##
    # Add your comments here.
    # Really.
    ##
    def place
    end
    end
    

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31. deve ser
    eficiente.
    #2
    

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32. Usuários Registrados
    
    
    <% User.recent.paginate(@page).each do |user| %>
    <%= link_to(user.full_name, user) %>
    <% end %>
    
    
    

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33. Registered Users
    
    
    <% User.recent.paginate(@page).each do |user| %>
    <%= link_to(user.full_name, user) %>
    <% end %>
    
    
    

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34. Registered Users
    
    
    <% @users.each do |user| %>
    <%= link_to(user.full_name, user) %>
    <% end %>
    
    
    

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35. Usuários Registrados
    
    
    <% @users.each do |user| %>
    <%= link_to(user.full_name, user) %>
    <% end %>
    
    
    

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36. avisar ao client
    caso haja algum
    erro.
    #3
    

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37. raise "Invalid HTTP request"
    

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38. raise "Invalid HTTP request"
    

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39. raise "Invalid HTTP request"
    vs.
    raise "Erro na autorização do Cartão
    de Crédito"
    

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40. raise "Erro na autorização do Cartão
    de Crédito"
    

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41. raise "Erro na autorização do Cartão
    de Crédito"
    

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42. fazer aquilo que
    seus métodos
    indicam fazer.
    #1
    

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43. deve ser eficiente.
    #2
    

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44. avisar ao client
    caso haja algum
    erro.
    #3
    

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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
    

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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
    

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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
    

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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
    

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49. Factory Method
    

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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
    

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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
    

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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
    

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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
    

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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
    

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55. class PlanSubscriber
    def self.build_for(user)
    end
    def subscribe(payment_info)
    end
    end
    

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56. class PlanSubscriber
    def self.build_for(user)
    end
    def subscribe(payment_info)
    end
    end
    

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57. require 'plan_subscriber'
    describe PlanSubscriber do
    end
    

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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
    

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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
    

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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
    

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61. Models
    !=
    AR::Base
    

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62. Rails não é o seu
    domain
    http://blog.firsthand.ca/2011/10/rails-is-not-your-
    application.html
    

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64. Design by Contract
    

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65. Pre-Conditions
    Post-Conditions
    Invariants
    

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66. Pre-Conditions
    

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67. E-mail deve ser válido.
    Produto deve estar disponível.
    

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68. Pre-Conditions
    Post-Conditions
    

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69. Assento deve estar reservado.
    Novo pagamento deve ser criado.
    

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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
    

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71. Pre-Conditions
    Post-Conditions
    Invariants
    

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72. Usuário deve estar ativado.
    Loja deve estar aberta.
    

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73. Pre-Conditions
    Post-Conditions
    Invariants
    

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75. Pirâmide de complexidade
    de models
    

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76. 0
    1
    2
    Pirâmide de complexidade
    de models
    

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77. 0
    Rails out-of-the-box
    1
    2
    Pirâmide de complexidade
    de models
    

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78. 0
    Rails out-of-the-box
    1
    Não utilizar métodos AR::Base
    nos controllers
    2
    Pirâmide de complexidade
    de models
    

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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
    

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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
    

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82. Mensagens
    

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83. Mensagens
    

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84. Protocolo
    

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85. Os Três Filtros de
    Interfaces
    

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86. Design by Contract
    

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87. Obrigado :)
    

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88. Poderosas Interfaces
    Rails
    Caike Souza
    RubyConf BR 2012
    

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