Models Models Every Where

Models form the backbone of our applications, but what are they and where to they come from? More importantly, do you have enough models or is your application missing some? Chris will show you how to spot missing models as well as create models with all of the goodies you’ve come to expect from Ruby on Rails. Along the way you’ll be introduced to ActiveAttr which makes it easy to construct models.

Transcript

1. Models Models
   Every Where
   The Rime of the ActiveModel
   

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2. SCALE MODEL?
   

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3. MODEL HOME?
   

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4. TYRA BANKS?
   

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5. What are models?
   

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6. app/models
   

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7. ActiveRecord
   

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8. Rails + Merb = 3.0
   

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9. The Great Decoupling
   ActiveRecord
   ActiveResource
   Sequel
   DataMapper
   Mongoid
   MongoMapper
   

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10. Why app/models?
    

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11. MODEL VIEW CONTROLLER (MVC)
    SMALLTALK AT XEROX PARC (1979)
    

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12. GUI Architectures
    Model View Controller
    Model View Adapter
    Model View Presenter
    Model View ViewModel
    Hierarchical Model View Controller
    

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13. Models, models
    every where
    Entities
    Value Objects
    Request Models
    Response Models
    Presentation Models
    

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14. “Model objects are the things in the
    system that you are trying to model.”
    David Heinemeier Hansson, 2004
    

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15. But what are models?
    

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16. MODEL VIEW CONTROLLER (MVC)
    SMALLTALK AT XEROX PARC (1979)
    

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17. MODELS REPRESENT KNOWLEDGE
    MODELS = KNOWLEDGE, KNOWLEDGE = POWER, MODELS = POWER
    

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18. MODELS AREN’T DEFINED BY PERSISTENCE
    THE ELEPHANT IN THE ROOM
    

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19. Examples of
    Models in Rails
    Rack::Request
    Rails::Application
    ActiveModel::Errors
    ActiveResource::Connection
    ActiveRecord::Associations::BelongsToAssociation
    

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20. SPOTTING MISSING MODELS
    

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21. WHERE DO MODELS HIDE?
    UNDER YOUR NOSE
    

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22. MODELS HIDE IN CONTROLLERS
    FAT CONTROLLERS?
    

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23. MODELS HIDE IN VIEWS
    LOGIC LADEN VIEWS?
    

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24. MODELS HIDE IN OTHER MODELS
    MODELS WITH TOO MUCH RESPONSIBILITY
    

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25. MODELS HIDE BITS OF THEMSELVES ALL OVER
    SPREAD IT AROUND
    

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26. SIGNS TO WATCH FOR
    

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27. MODEL VIEW CONTROLLER
    VIEWS AND CONTROLLERS WITHOUT A CLEAR SOURCE OF KNOWLEDGE
    X
    

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28. PRIMITIVE OBSESSION
    USING BUILT-IN TYPES TO DO A CLASS’ JOB
    

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29. LARGE CLASS
    MULTIPLE RESPONSIBILITIES
    

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30. Ideas for Models
    Address
    Contact Form
    Web Service Request/Response
    Presentation/View Model
    

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31. Example
    LoginRequest
    

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32. app/views/sessions/new.html.erb
    <% flash.each do |name, message| %>
    <%= content_tag(:p, message) %>
    <% end %>
    Log In
    <%= form_tag session_path do %>
    
    <%= label_tag 'email' %>
    
    <%= text_field_tag 'email', @email %>
    
    
    <%= label_tag 'password' %>
    
    <%= password_field_tag 'password', nil %>
    
    <%= link_to 'Forgot Password?', password_help_path %>
    
    
    <%= check_box_tag 'remember_me', '1', @remember_me.nil? ? true : @remember_me %>
    <%= label_tag 'remember_me' %>
    
    
    <%= submit_tag 'Log in' %>
    
    <% end %>
    

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33. app/views/sessions/new.html.erb
    <% flash.each do |name, message| %>
    <%= content_tag(:p, message) %>
    <% end %>
    Log In
    <%= form_tag session_path do %>
    <%# … %>
    <% end %>
    

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34. app/views/sessions/new.html.erb
    
    <%= label_tag 'email' %>
    
    <%= text_field_tag 'email', @email %>
    
    

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35. app/views/sessions/new.html.erb
    
    <%= label_tag 'password' %>
    
    <%= password_field_tag 'password', nil
    %>
    
    <%= link_to 'Forgot Password?',
    password_help_path %>
    
    

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36. app/views/sessions/new.html.erb
    
    <%= check_box_tag 'remember_me', '1',
    @remember_me.nil? ? true : @remember_me %>
    <%= label_tag 'remember_me' %>
    
    

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37. app/views/sessions/new.html.erb
    
    <%= submit_tag 'Log in' %>
    
    

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38. app/controllers/sessions_controller.rb
    class SessionsController < ApplicationController
    def new
    end
    def create
    logout_keeping_session!
    user = User.authenticate(params[:email], params[:password])
    if user
    self.current_user = user
    handle_remember_cookie! (params[:remember_me] == "1")
    flash[:notice] = "Logged in successfully."
    redirect_back_or_default root_url
    else
    errors = []
    errors << "Email can't be blank" if params[:email].blank?
    errors << "Password can't be blank" if params[:password].blank?
    errors << "Password is too short (minimum is 5 characters)" if params[:password].present? &&
    params[:password].length < 5
    flash.now[:error] = errors.any? ? errors.join(" ") : "Couldn't log you in as '#{params[:email]}'"
    logger.warn "Failed signin for '#{params[:email]}' at #{Time.now.utc}"
    @email = params[:email]
    @remember_me = !!params[:remember_me]
    render :new
    end
    end
    end
    

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39. app/controllers/sessions_controller.rb
    def new
    end
    

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40. app/controllers/sessions_controller.rb
    def create
    logout_keeping_session!
    

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41. app/controllers/sessions_controller.rb
    user = User.authenticate(params[:email],
    params[:password])
    

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42. app/controllers/sessions_controller.rb
    if user
    self.current_user = user
    handle_remember_cookie!
    (params[:remember_me] == "1")
    flash[:notice] = "Logged in
    successfully."
    redirect_back_or_default root_url
    else
    

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43. app/controllers/sessions_controller.rb
    errors = []
    errors << "Email can't be blank" if
    params[:email].blank?
    errors << "Password can't be blank" if
    params[:password].blank?
    errors << "Password is too short (minimum
    is 5 characters)" if
    params[:password].present? &&
    params[:password].length < 5
    

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44. app/controllers/sessions_controller.rb
    flash.now[:error] = errors.any? ?
    errors.join(" ") : "Couldn't log you in
    as '#{params[:email]}'"
    logger.warn "Failed signin for
    '#{params[:email]}' at #{Time.now.utc}"
    

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45. app/controllers/sessions_controller.rb
    @email = params[:email]
    @remember_me = !!params[:remember_me]
    render :new
    

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46. CODE SMELLS
    

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47. MODEL VIEW CONTROLLER
    VIEWS AND CONTROLLERS WITHOUT A CLEAR SOURCE OF KNOWLEDGE
    X
    

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48. SCATTERED KNOWLEDGE
    KNOWLEDGE IN CONTROLLERS AND VIEWS
    

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49. Refactor
    with Caution
    Refactor with Tests
    

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50. features/login.feature
    Feature: Logging in
    As an anonymous user with an account
    I want to log in to my account
    So that I can be myself
    Background:
    Given the following user exists:
    | first_name | last_name | email | password |
    | President | Skroob | skroob@spaceball1.com | 12345 |
    And I am on the login page
    

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51. features/login.feature
    Scenario: Login successfully
    When I fill in "Email" with
    "skroob@spaceball1.com"
    And I fill in "Password" with "12345"
    And the "Remember me" checkbox should be checked
    And I press "Log in"
    Then I should see "Logged in successfully"
    

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52. $ cucumber features/login.feature
    Using the default profile...
    .........
    1 scenario (1 passed)
    7 steps (7 passed)
    0m0.971s
    

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53. features/login.feature
    Scenario: Submit blank form
    When I uncheck "Remember me"
    And I press "Log in"
    Then I should see "Email can't be blank"
    And I should see "Password can't be blank"
    And I should not see "Couldn't log you in"
    And I should not see "Password is too
    short"
    And the "Remember me" checkbox should not
    be checked
    

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54. $ cucumber features/login.feature
    Using the default profile...
    ..................
    2 scenarios (2 passed)
    16 steps (16 passed)
    0m1.157s
    

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55. features/login.feature
    Scenario: Password too short
    When I fill in "Email" with
    "skroob@spaceball1.com"
    And I fill in "Password" with "1234"
    And I press "Log in"
    Then I should see "Password is too short
    (minimum is 5 characters)"
    And I should not see "Couldn't log you in
    as 'skroob@spaceball1.com'"
    And the "Password" field should not
    contain "1234"
    

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56. $ cucumber features/login.feature
    Using the default profile...
    ..........................
    3 scenarios (3 passed)
    24 steps (24 passed)
    0m1.409s
    

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57. features/login.feature
    Scenario: Incorrect password
    When I fill in "Email" with
    "skroob@spaceball1.com"
    And I fill in "Password" with "54321"
    And I press "Log in"
    Then I should see "Couldn't log you in as
    'skroob@spaceball1.com'"
    And the "Email" field should contain
    "skroob@spaceball1.com"
    And the "Password" field should not
    contain "54321"
    

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58. $ cucumber features/login.feature
    Using the default profile...
    ..................................
    4 scenarios (4 passed)
    32 steps (32 passed)
    0m1.563s
    

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59. View Slide

60. A New View On Life
    Log In
    <%= form_for @login_request, :url => session_path do |f| %>
    <% @login_request.errors.full_messages.each do |message| %>
    <%= content_tag(:p, message) %>
    <% end %>
    
    <%= f.label :email %>
    
    <%= f.text_field :email %>
    
    
    <%= f.label :password %>
    
    <%= f.password_field :password %>
    
    <%= link_to 'Forgot Password?', password_help_path %>
    
    
    <%= f.check_box :remember_me %>
    <%= f.label :remember_me %>
    
    
    <%= f.submit "Log in" %>
    
    <% end %>
    

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61. Before
    <% flash.each do |name, message| %>
    <%= content_tag(:p, message) %>
    <% end %>
    Log In
    <%= form_tag session_path do %>
    <%# … %>
    <% end %>
    

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62. After
    Log In
    <%= form_for @login_request, :url =>
    session_path do |f| %>
    <% @login_request.errors.full_messages.each
    do |message| %>
    <%= content_tag(:p, message) %>
    <% end %>
    <%# … %>
    <% end %>
    

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63. Before
    
    <%= label_tag 'email' %>
    
    <%= text_field_tag 'email', @email %>
    
    

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64. After
    
    <%= f.label :email %>
    
    <%= f.text_field :email %>
    
    

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65. Before
    
    <%= label_tag 'password' %>
    
    <%= password_field_tag 'password', nil
    %>
    
    <%= link_to 'Forgot Password?',
    password_help_path %>
    
    

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66. After
    
    <%= f.label :password %>
    
    <%= f.password_field :password %>
    
    <%= link_to 'Forgot Password?',
    password_help_path %>
    
    

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67. Before
    
    <%= check_box_tag 'remember_me', '1',
    @remember_me.nil? ? true : @remember_me %>
    <%= label_tag 'remember_me' %>
    
    

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68. After
    
    <%= f.check_box :remember_me %>
    <%= f.label :remember_me %>
    
    

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69. Before
    
    <%= submit_tag 'Log in' %>
    
    

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70. After
    
    <%= f.submit "Log in" %>
    
    

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71. Regaining Control
    class SessionsController < ApplicationController
    def new
    @login_request = LoginRequest.new
    end
    def create
    logout_keeping_session!
    @login_request = LoginRequest.new(params[:login_request])
    if @login_request.authenticate
    self.current_user = @login_request.user
    handle_remember_cookie! @login_request.remember_me?
    flash[:notice] = "Logged in successfully."
    redirect_back_or_default root_url
    else
    render :new
    end
    end
    end
    

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72. Before
    def new
    end
    

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73. After
    def new
    @login_request = LoginRequest.new
    end
    

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74. Before & After
    def create
    logout_keeping_session!
    

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75. Before
    user = User.authenticate(params[:email],
    params[:password])
    

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76. After
    @login_request =
    LoginRequest.new(params[:login_request])
    

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77. Before
    if user
    self.current_user = user
    handle_remember_cookie!
    (params[:remember_me] == "1")
    flash[:notice] = "Logged in
    successfully."
    redirect_back_or_default root_url
    else
    

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78. After
    if @login_request.authenticate
    self.current_user = @login_request.user
    handle_remember_cookie!
    @login_request.remember_me?
    flash[:notice] = "Logged in
    successfully."
    redirect_back_or_default root_url
    else
    

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79. Before Part 1
    errors = []
    errors << "Email can't be blank" if
    params[:email].blank?
    errors << "Password can't be blank" if
    params[:password].blank?
    errors << "Password is too short (minimum
    is 5 characters)" if
    params[:password].present? &&
    params[:password].length < 5
    

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80. Before Part 2
    flash.now[:error] = errors.any? ?
    errors.join(" ") : "Couldn't log you in
    as '#{params[:email]}'"
    logger.warn "Failed signin for
    '#{params[:email]}' at #{Time.now.utc}"
    

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81. Before Part 3
    @email = params[:email]
    @remember_me = !!params[:remember_me]
    render :new
    

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82. After
    render :new
    

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83. NOW WE LET THE TESTS TAKE THE WHEEL
    TEST DRIVEN DEVELOPMENT
    

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84. $ cucumber features/login.feature
    Using the default profile...
    .F.F------------------------------
    (::) failed steps (::)
    uninitialized constant
    SessionsController::LoginRequest
    (NameError)
    

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85. app/models/login_request.rb
    class LoginRequest
    end
    

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86. $ cucumber features/login.feature
    Using the default profile...
    .F.F------------------------------
    (::) failed steps (::)
    undefined method `model_name' for
    LoginRequest:Class
    (ActionView::Template::Error
    

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87. The ActiveModel API
    #to_model
    

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88. ActiveModel API
    #persisted?
    #valid?
    #errors
    #[]
    #full_messages
    #to_key
    #to_param
    #to_partial_path
    .model_name
    #human
    #singular
    #plural
    

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89. When does a model need
    to be an ActiveModel?
    Railties
    ActiveSupport
    ActiveRecord
    ActiveResource
    ActiveModel
    ActionMailer
    

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90. ActiveModel API
    is for ActionPack
    

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91. When does ActionPack
    need an ActiveModel?
    Polymorphic Routes (url_for)
    Partial Rendering (render)
    Record Identification (dom_class, dom_id)
    Form Building (form_for)
    

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92. ActiveModel::Lint::Tests
    

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93. $ rspec spec/models/
    login_request_spec.rb
    FFFFFFF
    Failures:
    1) LoginRequest it should behave like
    ActiveModel test model naming
    Failure/Error: send test
    Test::Unit::AssertionFailedError:
    The object should respond_to
    to_model.
    is not true.
    

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94. app/models/login_request.rb
    class LoginRequest
    def to_model
    self
    end
    end
    

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95. $ rspec spec/models/
    login_request_spec.rb
    FFFFFFF
    Failures:
    1) LoginRequest it should behave like
    ActiveModel test model naming
    Failure/Error: send test
    Test::Unit::AssertionFailedError:
    The object should respond_to
    model_name.
    is not true.
    

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96. The ActiveModel Library
    gem install activemodel
    

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97. ActiveModel::Naming
    .model_name
    #human
    #singular
    #plural
    

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98. app/models/login_request.rb
    class LoginRequest
    extend ActiveModel::Naming
    def to_model
    self
    end
    end
    

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99. $ rspec spec/models/
    login_request_spec.rb
    .FFFFFF
    Failures:
    1) LoginRequest it should behave like
    ActiveModel test to param
    Failure/Error: send test
    Test::Unit::AssertionFailedError:
    to_param should return nil when
    `persisted?` returns false.
    is not true.
    

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100. ActiveModel::Conversion
     #to_model
     #to_key
     #to_param
     

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101. app/models/login_request.rb
     class LoginRequest
     extend ActiveModel::Naming
     include ActiveModel::Conversion
     end
     

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102. $ rspec spec/models/
     login_request_spec.rb
     ...FFFF
     Failures:
     1) LoginRequest it should behave like
     ActiveModel test valid?
     Failure/Error: send test
     Test::Unit::AssertionFailedError:
     The model should respond to valid?.
     is not true.
     

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103. ActiveModel::Validations
     #valid?
     #errors
     .validates_acceptance_of
     .validates_confirmation_of
     .validates_exclusion_of
     .validates_format_of
     .validates_inclusion_of
     .validates_length_of
     .validates_numericality_of
     .validates_presence_of
     

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104. app/models/login_request.rb
     class LoginRequest
     extend ActiveModel::Naming
     include ActiveModel::Conversion
     include ActiveModel::Validations
     end
     

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105. $ rspec spec/models/
     login_request_spec.rb
     ......F
     Failures:
     1) LoginRequest it should behave like
     ActiveModel test persisted?
     Failure/Error: send test
     Test::Unit::AssertionFailedError:
     The model should respond to
     persisted?.
     is not true.
     

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106. app/models/login_request.rb
     class LoginRequest
     extend ActiveModel::Naming
     include ActiveModel::Conversion
     include ActiveModel::Validations
     def persisted?
     false
     end
     end
     

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107. $ rspec spec/models/
     login_request_spec.rb
     .......
     Finished in 0.00835 seconds
     7 examples, 0 failures
     

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108. $ cucumber features/login.feature
     Using the default profile...
     .F.F------------------------------
     (::) failed steps (::)
     undefined method `email' for
     #
     (ActionView::Template::Error)
     

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109. app/models/login_request.rb
     attr_accessor :email, :password,
     :remember_me
     

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110. $ cucumber features/login.feature
     Using the default profile...
     ......F--...F-----....F---....F---
     (::) failed steps (::)
     expected false to be true
     features/login.feature:15:in `And the
     "Remember me" checkbox should be
     checked'
     

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111. app/models/login_request.rb
     def initialize
     self.remember_me = true
     end
     

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112. $ cucumber features/login.feature
     Using the default profile...
     .......F-...F-----....F---....F---
     (::) failed steps (::)
     wrong number of arguments (1 for 0)
     (ArgumentError)
     ./app/controllers/
     sessions_controller.rb:10:in
     `initialize'
     

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113. app/controllers/sessions_controller.rb
     @login_request =
     LoginRequest.new(params[:login_request])
     

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114. app/models/login_request.rb
     def initialize(new_attributes={})
     self.remember_me = true
     new_attributes.each do |attribute, value|
     if respond_to?("#{attribute}=")
     send("#{attribute}=", value)
     end
     end
     end
     

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115. $ cucumber features/login.feature
     Using the default profile...
     .......F-...F-----....F---....F---
     (::) failed steps (::)
     undefined method `authenticate' for
     #
     (NoMethodError)
     ./app/controllers/
     sessions_controller.rb:12:in `create'
     

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116. app/models/login_request.rb
     def authenticate
     success = valid?
     logger.warn "Failed signin for
     #{email.inspect}" unless success
     success
     end
     def logger
     Rails.logger
     end
     

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117. $ cucumber features/login.feature
     Using the default profile...
     .......F-...F-----....F---....F---
     (::) failed steps (::)
     undefined method `user' for
     #
     (NoMethodError)
     ./app/controllers/
     sessions_controller.rb:13:in `create'
     

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118. app/models/login_request.rb
     def user
     return @user if
     instance_variable_defined? "@user"
     @user = User.authenticate(email,
     password)
     end
     

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119. $ cucumber features/login.feature
     Using the default profile...
     .......F-...F-----....F---....F---
     (::) failed steps (::)
     undefined method `remember_me?' for
     #
     (NoMethodError)
     ./app/controllers/
     sessions_controller.rb:14:in `create'
     

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120. app/models/login_request.rb
     def remember_me?
     remember_me.present?
     end
     

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121. $ cucumber features/login.feature
     Using the default profile...
     .............F----.....F--.....F--
     (::) failed steps (::)
     expected there to be content "Email
     can't be blank"
     

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122. app/models/login_request.rb
     validates_presence_of :email, :password
     validates_length_of :password,
     :minimum => 5, :allow_blank => true
     

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123. $ cucumber features/login.feature
     Using the default profile...
     ...............................F--
     (::) failed steps (::)
     expected there to be content
     "Couldn't log you in as
     'skroob@spaceball1.com'"
     

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124. app/models/login_request.rb
     validate do
     if errors.empty? && user.blank?
     errors.add :base, "Couldn't log you in
     as '#{email}'"
     end
     end
     

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125. $ cucumber features/login.feature
     Using the default profile...
     ..................................
     4 scenarios (4 passed)
     32 steps (32 passed)
     0m1.599s
     

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126. class LoginRequest
     extend ActiveModel::Naming
     include ActiveModel::Conversion
     include ActiveModel::Validations
     def persisted?
     false
     end
     attr_accessor :email, :password, :remember_me
     def initialize(new_attributes={})
     self.remember_me = true
     new_attributes.each do |attribute, value|
     if respond_to?("#{attribute}=")
     send("#{attribute}=", value)
     end
     end
     end
     def authenticate
     success = valid?
     logger.warn "Failed signin for #{email.inspect}" unless success
     success
     end
     def logger
     Rails.logger
     end
     def user
     return @user if instance_variable_defined? "@user"
     @user = User.authenticate(email, password)
     end
     def remember_me?
     remember_me.present?
     end
     validates_presence_of :email, :password
     validates_length_of :password, :minimum => 5, :allow_blank => true
     validate do
     if errors.empty? && user.blank?
     errors.add :base, "Couldn't log you in as '#{email}'"
     end
     end
     end
     

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127. ActiveAttr
     What ActiveModel Left Out
     

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128. Rocket Fuel
     For your models
     

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129. BasicModel
     class Person
     include ActiveAttr::BasicModel
     end
     Person.model_name.plural #=> "people"
     person = Person.new
     person.valid? #=> true
     person.errors.full_messages #=> []
     

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130. Before
     extend ActiveModel::Naming
     include ActiveModel::Conversion
     include ActiveModel::Validations
     def persisted?
     false
     end
     

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131. After
     include ActiveAttr::BasicModel
     

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132. Attributes
     class Person
     include ActiveAttr::Attributes
     attribute :first_name
     attribute :last_name
     end
     person = Person.new
     person.first_name = "Chris"
     person.last_name = "Griego"
     person.attributes #=> {"first_name"=>"Chris",
     "last_name"=>"Griego"}
     

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133. Before
     attr_accessor :email, :password,
     :remember_me
     

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134. After
     include ActiveAttr::Attributes
     attribute :email
     attribute :password
     attribute :remember_me
     

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135. QueryAttributes
     class Person
     include ActiveAttr::QueryAttributes
     attribute :first_name
     attribute :last_name
     end
     person = Person.new
     person.first_name = "Chris"
     person.first_name? #=> true
     person.last_name? #=> false
     

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136. Before
     def remember_me?
     remember_me.present?
     end
     

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137. After
     include ActiveAttr::QueryAttributes
     

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138. AttributeDefaults
     class Person
     include ActiveAttr::AttributeDefaults
     attribute :first_name, :default => "John"
     attribute :last_name, :default => "Doe"
     end
     person = Person.new
     person.first_name #=> "John"
     person.last_name #=> "Doe"
     

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139. Before
     attribute :remember_me
     def initialize(new_attributes={})
     self.remember_me = true
     new_attributes.each do |attribute, value|
     if respond_to?("#{attribute}=")
     send("#{attribute}=", value)
     end
     end
     end
     

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140. After
     include ActiveAttr::AttributeDefaults
     attribute :remember_me, :default => true
     def initialize(new_attributes={})
     new_attributes.each do |attribute, value|
     if respond_to?("#{attribute}=")
     send("#{attribute}=", value)
     end
     end
     end
     

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141. MassAssignment
     class Person
     include ActiveAttr::MassAssignment
     attr_accessor :first_name, :last_name
     end
     person = Person.new(:first_name => "Chris")
     person.attributes = { :last_name => "Griego" }
     person.first_name #=> "Chris"
     person.last_name #=> "Griego"
     

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142. Before
     def initialize(new_attributes={})
     new_attributes.each do |attribute, value|
     if respond_to?("#{attribute}=")
     send("#{attribute}=", value)
     end
     end
     end
     

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143. After
     include ActiveAttr::MassAssignment
     

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144. Logger
     class Person
     include ActiveAttr::Logger
     end
     Person.logger = Logger.new(STDOUT)
     Person.logger? #=> true
     Person.logger.info "Logging an informational message"
     person = Person.new
     person.logger? #=> true
     person.logger = Logger.new(STDERR)
     person.logger.warn "Logging a warning message"
     

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145. Before
     def logger
     Rails.logger
     end
     

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146. After
     include ActiveAttr::Logger
     

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147. Model
     class Person
     include ActiveAttr::Model
     end
     

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148. Before
     include ActiveAttr::BasicModel
     include ActiveAttr::Attributes
     include ActiveAttr::QueryAttributes
     include ActiveAttr::AttributeDefaults
     include ActiveAttr::MassAssignment
     include ActiveAttr::Logger
     

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149. After
     include ActiveAttr::Model
     

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150. class LoginRequest
     include ActiveAttr::Model
     attribute :email
     attribute :password
     attribute :remember_me, :default => true
     def authenticate
     success = valid?
     logger.warn "Failed signin for #{email.inspect}" unless success
     success
     end
     def user
     return @user if instance_variable_defined? "@user"
     @user = User.authenticate(email, password)
     end
     validates_presence_of :email, :password
     validates_length_of :password, :minimum => 5, :allow_blank => true
     validate do
     if errors.empty? && user.blank?
     errors.add :base, "Couldn't log you in as '#{email}'"
     end
     end
     end
     

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151. $ cucumber features/login.feature
     Using the default profile...
     ..................................
     4 scenarios (4 passed)
     32 steps (32 passed)
     0m1.731s
     

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152. $ rspec spec/models/
     login_request_spec.rb
     ..................................
     Finished in 0.09344 seconds
     34 examples, 0 failures
     

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153. MassAssignmentSecurity
     class Person
     include ActiveAttr::MassAssignmentSecurity
     attr_accessor :first_name, :last_name
     attr_protected :last_name
     end
     person = Person.new(:first_name => "Chris", :last_name =>
     "Griego")
     person.first_name #=> "Chris"
     person.last_name #=> nil
     

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154. BlockInitialization
     class Person
     include ActiveAttr::BlockInitialization
     attr_accessor :first_name, :last_name
     end
     person = Person.new do |p|
     p.first_name = "Chris"
     p.last_name = "Griego"
     end
     person.first_name #=> "Chris"
     person.last_name #=> "Griego"
     

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155. TypecastedAttributes
     class Person
     include ActiveAttr::TypecastedAttributes
     attribute :age, :type => Integer
     end
     person = Person.new
     person.age = "29"
     person.age #=> 29
     

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156. Rails Integration
     gem "active_attr"
     

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157. RSpec Integration
     require "active_attr/rspec"
     describe Person do
     it { should
     have_attribute(:first_name).with_default_value_of("John") }
     end
     

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158. ActiveAttr Roadmap
     Multi-parameter Attributes
     Non-nullable Attributes
     Rails Generators
     Associations
     Nested Attributes
     

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159. Image Credits
     The Elephant in the Room by Bit Boy http://www.flickr.com/photos/bitboy/246805948/
     Binoculars by Evan Long http://www.flickr.com/photos/clover_1/1200447508/
     Hiding by Susan Sermoneta http://www.flickr.com/photos/en321/33868864/
     PS3 Controller by Mauro Monti http://www.flickr.com/photos/kilamdil/393406895/
     Xbox Controller by Alexa Booth http://www.flickr.com/photos/xabooth/2208511222/
     Nintendo Gamecube Controller by Andy Zeigert http://www.flickr.com/photos/andyz/40676384/
     View and Rooftops by C.J. Peters http://www.flickr.com/photos/conlawprof/266890004/
     Glittering City View by William Cho http://www.flickr.com/photos/adforce1/3876421475/
     Korean Signs by Taylor Sloan http://www.flickr.com/photos/taylorsloan/4477937283/
     Flint Knapper by Wessex Archaeology http://www.flickr.com/photos/wessexarchaeology/56515302/
     Hat Collection by lokarta http://www.flickr.com/photos/lokar/4071667927/
     Caution Men by Alyson Hurt http://www.flickr.com/photos/alykat/2930096885/
     Smells by Larissa http://www.flickr.com/photos/lara68/3492153226/
     Wheel Building by Andrew Schwab http://www.flickr.com/photos/aschwab/3621428436/
     Socony Gas Can by BEV Norton http://www.flickr.com/photos/catchesthelight/2225634867/
     Statue of the Ancient Mariner Photo by pshab http://www.flickr.com/photos/pshab/460051997/
     

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160. He went like one that hath
     been stunned,
     And is of sense forlorn:
     A sadder and a wiser man,
     He rose the morrow morn.
     

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