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Adventures Golden Path Jeff Casimir / Jumpstart Lab / @j3 on the Monday, March 26, 12

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Jumpstart Lab & LivingSocial Monday, March 26, 12

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2005 Back in the year Monday, March 26, 12

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This is no JSP Monday, March 26, 12

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Love? How do you fall in Monday, March 26, 12

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10X Productivity This new world promised Monday, March 26, 12

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“Joy” This new world promised Monday, March 26, 12

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“Beta” Books Monday, March 26, 12

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Rails 1 We can do what you can do. Monday, March 26, 12

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Rails 2 Pushing the state of the art Monday, March 26, 12

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Rails 3 Foundation for the future Monday, March 26, 12

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Rails 4 Back to happiness? Monday, March 26, 12

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Why Rails Works The Golden Path Monday, March 26, 12

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Rounding the Wheel We know better Monday, March 26, 12

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The Router Part 1 Monday, March 26, 12

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“YARR!” That’s not it Monday, March 26, 12

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routes.rb Blog::Application.routes.draw do # The priority is based upon order of creation: # first created -> highest priority. # Sample of regular route: # match 'products/:id' => 'catalog#view' # Keep in mind you can assign values other than :controller and :action # Sample of named route: # match 'products/:id/purchase' => 'catalog#purchase', :as => :purchase # This route can be invoked with purchase_url(:id => product.id) # Sample resource route (maps HTTP verbs to controller actions automatically): # resources :products # Sample resource route with options: # resources :products do # member do # get 'short' Monday, March 26, 12

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Simple routes.rb Blog::Application.routes.draw do # EXAMPLES # resources :products # root :to => 'welcome#index' # MORE INFORMATION # Run "rake routes" to see the routes available # http://guides.rubyonrails.org/routing.html end Monday, March 26, 12

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Route Helpers But wait, there’s more: Monday, March 26, 12

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“I want to link to an article” No problem! Monday, March 26, 12

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articles_path Adding path or url Monday, March 26, 12

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“Where does that method come from?” Uhh...don’t worry about it. Monday, March 26, 12

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“Can I play with routes from the console?” I think so, kinda. Monday, March 26, 12

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This is not OOP Functional View Helpers Monday, March 26, 12

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Route As a singleton class Monday, March 26, 12

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Route.articles Generates the index path Monday, March 26, 12

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Route.article(1) Generates the show path Monday, March 26, 12

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Route.article(1).edit Generates the edit path Monday, March 26, 12

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Route Experiments blog$ rails console Loading development environment 001 > Route.methods(false) => [:articles, :article] 002 > Route.articles => /articles/ 003 > Route.article(1) => /articles/1 004 > Route.article(1).edit => /articles/1/edit <%= link_to "Articles", Route.articles %> Monday, March 26, 12

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“It’s an object system, I know this!” Monday, March 26, 12

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Routing Conclusions •Create a Route object to represent routes in the system •Build routes like ARel builds queries Monday, March 26, 12

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System Level Part 2 Monday, March 26, 12

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“What’s Rake?” It’s “ruby-make,” it’s for doing things with your app from the command line. Monday, March 26, 12

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Let’s generate our first model... “Ok, cool.” Here’s how we do it at the terminal: rails generate model Article Monday, March 26, 12

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“I thought we used rake for manipulating the app?” Ummm...we use both rake and rails, I guess. “???” Monday, March 26, 12

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[:generate, :destroy, :server, :console].each do | command| desc "Proof-of-concept rails CLI proxy for #{command}" task command do system("rails #{command} #{ARGV[1..-1].join(' ')}") exit end end Proof of Concept Monday, March 26, 12

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Rake Everything blog$ rake generate model Article title:string body:string invoke active_record create db/migrate/20120322132256_create_articles.rb create app/models/article.rb ... blog$ rake db:migrate == CreateArticles: migrating ================================================= -- create_table(:articles) ... blog$ rake console Loading development environment 001 > Monday, March 26, 12

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System-Level Conclusions •Generate apps using rails •Then everything else happens through rake Monday, March 26, 12

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Models Part 3 Monday, March 26, 12

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Let’s check out the model we generated... Monday, March 26, 12

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class Article < ActiveRecord::Base end article.rb Monday, March 26, 12

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“Is the model important?” The most important! “So why is it blank?” ... Monday, March 26, 12

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Mass-Assignment Monday, March 26, 12

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Remember the h helper? Monday, March 26, 12

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Safe by Default class Article < ActiveRecord::Base # Enable mass-assignment for attributes with # attr_accessible :title, :body end module Blog class Application < Rails::Application # Block all model attributes from mass assignment # unless attr_accessible is used config.attributes_protected_by_default = true #... end end Monday, March 26, 12

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Proof of Concept ActiveRecord::Base.class_eval if Application.config.attributes_protected_by_default attr_accessible end end blog$ rake console Loading development environment 001 > Article.create(:title => "Hello, world") ActiveModel::MassAssignmentSecurity::Error: Can't mass-assign protected attributes: title Monday, March 26, 12

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“So the model is just a Ruby object?” Yep! “But I thought Ruby prefers composition over inheritance?” Uhh... Monday, March 26, 12

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class Article include ActiveRecord::Base # Enable mass-assignment for ... # attr_accessible :title, :body end “That makes more sense, but what is a ‘Base’?” Monday, March 26, 12

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class Article include ActiveRecord::Record # Enable mass-assignment for ... # attr_accesible :title, :body end “Oh, it’s a Record!” Monday, March 26, 12

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“What does a model do, anyway?” It’s responsible for persistence and business logic “Did you just say and?” Monday, March 26, 12

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Persistence Monday, March 26, 12

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Single Responsibility module ArticlePersistence include ActiveRecord::Record has_many :comments belongs_to :author end class Article include ArticlePersistence end Monday, March 26, 12

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“Why doesn’t Rails do that by default?” It should! Monday, March 26, 12

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blog$ rake generate model Comment body:text article_id:integer invoke active_record create db/migrate/20120322142641_create_com... create app/models/comment.rb create app/persistence/comment_persistence.rb invoke test_unit create test/unit/comment_test.rb create test/unit/comment_persistence_test.rb create test/fixtures/comments.yml blog$ In the Generators Monday, March 26, 12

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Model Layer Conclusions •Add attr_accessible to generated models •Utilize ActiveRecord via module inclusion •Break persistence/logic into two components Monday, March 26, 12

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Controllers & Views Part 4 Monday, March 26, 12

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Let’s check out the controller action to list articles: class ArticlesController < ApplicationController def index @articles = Article.all end end “Why is that an instance variable?” Monday, March 26, 12

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That’s how we get it over to the view template. “So they share state? I thought MVC was three components?” ...it’s complicated. Monday, March 26, 12

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Status Quo

Articles

<% @articles.each do |article| %>
  • <%= link_to article.title, article_path(article) %> <% end %> Monday, March 26, 12

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    Accessor Method

    Articles

    <% articles.each do |article| %>
  • <%= link_to article.title, Route.article(article) %> <% end %> Monday, March 26, 12

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    class ArticlesController < ApplicationController attr_viewable :articles def index self.articles = Article.all end In the Controller Monday, March 26, 12

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    Proof of Concept module AttributeViewer def attr_viewable(*names) names.each do |name| attr_accessor name helper_method name private "#{name}=".to_sym end end end class ApplicationController < ActionController::Base protect_from_forgery include AttributeViewable end Monday, March 26, 12

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    Controller/View Conclusions •Instance variables are a code smell •Use helper methods to expose data to the view template Monday, March 26, 12

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    • Wrap the router into an object • Unify the system-level with rake • attr_accessible by default • Break logic from persistence • Eliminate instance vars from views Adventures on the Golden Path Jeff Casimir / Jumpstart Lab / @j3 Monday, March 26, 12