Models Models Every Where

Transcript

1. Models Models Every Where The Rime of the ActiveModel

2. SCALE MODEL?

3. MODEL HOME?

4. TYRA BANKS?

5. What are models?

6. app/models

7. ActiveRecord

8. Rails + Merb = 3.0

9. The Great Decoupling ActiveRecord ActiveResource Sequel DataMapper Mongoid MongoMapper

10. Why app/models?

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

12. GUI Architectures Model View Controller Model View Adapter Model View

    Presenter Model View ViewModel Hierarchical Model View Controller

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

    Models Presentation Models

14. “Model objects are the things in the system that you

    are trying to model.” David Heinemeier Hansson, 2004

15. But what are models?

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

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

    = POWER

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

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

20. SPOTTING MISSING MODELS

21. WHERE DO MODELS HIDE? UNDER YOUR NOSE

22. MODELS HIDE IN CONTROLLERS FAT CONTROLLERS?

23. MODELS HIDE IN VIEWS LOGIC LADEN VIEWS?

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

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

26. SIGNS TO WATCH FOR

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

    OF KNOWLEDGE X

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

29. LARGE CLASS MULTIPLE RESPONSIBILITIES

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

    Model

31. Example LoginRequest

32. app/views/sessions/new.html.erb <% flash.each do |name, message| %> <%= content_tag(:p, message)

    %> <% end %> <h1>Log In</h1> <%= form_tag session_path do %> <div class="field"> <%= label_tag 'email' %><br /> <%= text_field_tag 'email', @email %> </div> <div class="field"> <%= label_tag 'password' %><br/> <%= password_field_tag 'password', nil %><br /> <%= link_to 'Forgot Password?', password_help_path %> </div> <div class="field"> <%= check_box_tag 'remember_me', '1', @remember_me.nil? ? true : @remember_me %> <%= label_tag 'remember_me' %> </div> <div class="actions"> <%= submit_tag 'Log in' %> </div> <% end %>

33. app/views/sessions/new.html.erb <% flash.each do |name, message| %> <%= content_tag(:p, message)

    %> <% end %> <h1>Log In</h1> <%= form_tag session_path do %> <%# … %> <% end %>

34. app/views/sessions/new.html.erb <div class="field"> <%= label_tag 'email' %><br /> <%= text_field_tag

    'email', @email %> </div>

35. app/views/sessions/new.html.erb <div class="field"> <%= label_tag 'password' %><br/> <%= password_field_tag 'password',

    nil %><br /> <%= link_to 'Forgot Password?', password_help_path %> </div>

36. app/views/sessions/new.html.erb <div class="field"> <%= check_box_tag 'remember_me', '1', @remember_me.nil? ? true

    : @remember_me %> <%= label_tag 'remember_me' %> </div>

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

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

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

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

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

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

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

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}"

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

46. CODE SMELLS

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

    OF KNOWLEDGE X

48. SCATTERED KNOWLEDGE KNOWLEDGE IN CONTROLLERS AND VIEWS

49. Refactor with Caution Refactor with Tests

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 | [email protected] | 12345 | And I am on the login page

51. features/login.feature Scenario: Login successfully When I fill in "Email" with

    "[email protected]" 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"

52. $ cucumber features/login.feature Using the default profile... ......... 1 scenario

    (1 passed) 7 steps (7 passed) 0m0.971s

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

54. $ cucumber features/login.feature Using the default profile... .................. 2 scenarios

    (2 passed) 16 steps (16 passed) 0m1.157s

55. features/login.feature Scenario: Password too short When I fill in "Email"

    with "[email protected]" 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 '[email protected]'" And the "Password" field should not contain "1234"

56. $ cucumber features/login.feature Using the default profile... .......................... 3 scenarios

    (3 passed) 24 steps (24 passed) 0m1.409s

57. features/login.feature Scenario: Incorrect password When I fill in "Email" with

    "[email protected]" And I fill in "Password" with "54321" And I press "Log in" Then I should see "Couldn't log you in as '[email protected]'" And the "Email" field should contain "[email protected]" And the "Password" field should not contain "54321"

58. $ cucumber features/login.feature Using the default profile... .................................. 4 scenarios

    (4 passed) 32 steps (32 passed) 0m1.563s
59. None

60. A New View On Life <h1>Log In</h1> <%= form_for @login_request,

    :url => session_path do |f| %> <% @login_request.errors.full_messages.each do |message| %> <%= content_tag(:p, message) %> <% end %> <div class="field"> <%= f.label :email %><br /> <%= f.text_field :email %> </div> <div class="field"> <%= f.label :password %><br /> <%= f.password_field :password %><br /> <%= link_to 'Forgot Password?', password_help_path %> </div> <div class="field"> <%= f.check_box :remember_me %> <%= f.label :remember_me %> </div> <div class="actions"> <%= f.submit "Log in" %> </div> <% end %>

61. Before <% flash.each do |name, message| %> <%= content_tag(:p, message)

    %> <% end %> <h1>Log In</h1> <%= form_tag session_path do %> <%# … %> <% end %>

62. After <h1>Log In</h1> <%= form_for @login_request, :url => session_path do

    |f| %> <% @login_request.errors.full_messages.each do |message| %> <%= content_tag(:p, message) %> <% end %> <%# … %> <% end %>

63. Before <div class="field"> <%= label_tag 'email' %><br /> <%= text_field_tag

    'email', @email %> </div>

64. After <div class="field"> <%= f.label :email %><br /> <%= f.text_field

    :email %> </div>

65. Before <div class="field"> <%= label_tag 'password' %><br/> <%= password_field_tag 'password',

    nil %><br /> <%= link_to 'Forgot Password?', password_help_path %> </div>

66. After <div class="field"> <%= f.label :password %><br /> <%= f.password_field

    :password %><br /> <%= link_to 'Forgot Password?', password_help_path %> </div>

67. Before <div class="field"> <%= check_box_tag 'remember_me', '1', @remember_me.nil? ? true

    : @remember_me %> <%= label_tag 'remember_me' %> </div>

68. After <div class="field"> <%= f.check_box :remember_me %> <%= f.label :remember_me

    %> </div>

69. Before <div class="actions"> <%= submit_tag 'Log in' %> </div>

70. After <div class="actions"> <%= f.submit "Log in" %> </div>

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

72. Before def new end

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

74. Before & After def create logout_keeping_session!

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

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

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

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

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

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}"

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

    :new

82. After render :new

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

    DEVELOPMENT

84. $ cucumber features/login.feature Using the default profile... .F.F------------------------------ (::) failed

    steps (::) uninitialized constant SessionsController::LoginRequest (NameError)

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

86. $ cucumber features/login.feature Using the default profile... .F.F------------------------------ (::) failed

    steps (::) undefined method `model_name' for LoginRequest:Class (ActionView::Template::Error

87. The ActiveModel API #to_model

88. ActiveModel API #persisted? #valid? #errors #[] #full_messages #to_key #to_param #to_partial_path

    .model_name #human #singular #plural

89. When does a model need to be an ActiveModel? Railties

    ActiveSupport ActiveRecord ActiveResource ActiveModel ActionMailer

90. ActiveModel API is for ActionPack

91. When does ActionPack need an ActiveModel? Polymorphic Routes (url_for) Partial

    Rendering (render) Record Identification (dom_class, dom_id) Form Building (form_for)

92. ActiveModel::Lint::Tests

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. <false> is not true.

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

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. <false> is not true.

96. The ActiveModel Library gem install activemodel

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

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

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. <false> is not true.

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

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

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?. <false> is not true.

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

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

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?. <false> is not true.

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

     persisted? false end end

107. $ rspec spec/models/ login_request_spec.rb ....... Finished in 0.00835 seconds 7

     examples, 0 failures

108. $ cucumber features/login.feature Using the default profile... .F.F------------------------------ (::) failed

     steps (::) undefined method `email' for #<LoginRequest:0x104c55fd0> (ActionView::Template::Error)

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

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'

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

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'

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

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

115. $ cucumber features/login.feature Using the default profile... .......F-...F-----....F---....F--- (::) failed

     steps (::) undefined method `authenticate' for #<LoginRequest:0x1178886b0> (NoMethodError) ./app/controllers/ sessions_controller.rb:12:in `create'

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

117. $ cucumber features/login.feature Using the default profile... .......F-...F-----....F---....F--- (::) failed

     steps (::) undefined method `user' for #<LoginRequest:0x107bd64f8> (NoMethodError) ./app/controllers/ sessions_controller.rb:13:in `create'

118. app/models/login_request.rb def user return @user if instance_variable_defined? "@user" @user =

     User.authenticate(email, password) end

119. $ cucumber features/login.feature Using the default profile... .......F-...F-----....F---....F--- (::) failed

     steps (::) undefined method `remember_me?' for #<LoginRequest:0x111efadf0> (NoMethodError) ./app/controllers/ sessions_controller.rb:14:in `create'

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

121. $ cucumber features/login.feature Using the default profile... .............F----.....F--.....F-- (::) failed

     steps (::) expected there to be content "Email can't be blank"

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

     => true

123. $ cucumber features/login.feature Using the default profile... ...............................F-- (::) failed

     steps (::) expected there to be content "Couldn't log you in as '[email protected]'"

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

125. $ cucumber features/login.feature Using the default profile... .................................. 4 scenarios

     (4 passed) 32 steps (32 passed) 0m1.599s

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

127. ActiveAttr What ActiveModel Left Out

128. Rocket Fuel For your models

129. BasicModel class Person include ActiveAttr::BasicModel end Person.model_name.plural #=> "people" person

     = Person.new person.valid? #=> true person.errors.full_messages #=> []

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

     end

131. After include ActiveAttr::BasicModel

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"}

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

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

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

136. Before def remember_me? remember_me.present? end

137. After include ActiveAttr::QueryAttributes

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"

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

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

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"

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

     value) end end end

143. After include ActiveAttr::MassAssignment

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"

145. Before def logger Rails.logger end

146. After include ActiveAttr::Logger

147. Model class Person include ActiveAttr::Model end

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

     ActiveAttr::MassAssignment include ActiveAttr::Logger

149. After include ActiveAttr::Model

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

151. $ cucumber features/login.feature Using the default profile... .................................. 4 scenarios

     (4 passed) 32 steps (32 passed) 0m1.731s

152. $ rspec spec/models/ login_request_spec.rb .................................. Finished in 0.09344 seconds 34

     examples, 0 failures

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

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"

155. TypecastedAttributes class Person include ActiveAttr::TypecastedAttributes attribute :age, :type => Integer

     end person = Person.new person.age = "29" person.age #=> 29

156. Rails Integration gem "active_attr"

157. RSpec Integration require "active_attr/rspec" describe Person do it { should

     have_attribute(:first_name).with_default_value_of("John") } end

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

     Attributes

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/

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.