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
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 | skroob@spaceball1.com | 12345 | And I am on the login page
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"
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 "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"
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 "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"
58. $ cucumber features/login.feature Using the default profile... .................................. 4 scenarios (4 passed) 32 steps (32 passed) 0m1.563s
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 'skroob@spaceball1.com'"
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.