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PATTERNS FALACY! Luciano Sousa http://lucianosousa.net twitter: @lucianosousa github: lucianosousa v2

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#WHOAMI?

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#War Feelings

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SOCITRIP.COM

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DISCLAIMER

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Focus on ideas, not examples Think about what you are you doing with your apps Try solve your problems out of the box

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A BRIEF HISTORY OF TIME

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MVC

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MVC FRAMEWORK BASED RAILS

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MVC Definition Model–view–controller (MVC) is a software architecture pattern which separates the representation of information from the user's interaction with it. (...) ! • A controller can send commands to its associated view to change the view's presentation of the model (e.g., by scrolling through a document). It can also send commands to the model to update the model's state (e.g., editing a document). • A model notifies its associated views and controllers when there has been a change in its state. This notification allows the views to produce updated output, and the controllers to change the available set of commands (...). • A view requests from the model the information that it needs to generate an output representation to the user. http://en.wikipedia.org/wiki/Model-view-controller

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LIVE EXAMPLE

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‘PATTERNS’

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Oh, wait... Patterns?

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like...

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R.I.P. OBSERVERS

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https://blog.engineyard.com/2013/rails-4-changes ! http://ruby5.envylabs.com/episodes/331-episode-327- december-4-2012/stories/2882-observers-and-sweepers-were- removed-from-rails ! http://samuelmullen.com/2013/05/the-problem-with-rails-callbacks/ Observers

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SCAFFOLD

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Sloth

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and... not least

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CoffeeScript

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Bad, bad server. No Donut for you

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http://codon.com/the-dhh-problem

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RAILS & RAILS 4

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TestUnit x RSpec

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RSPEC • pending examples <3 • matchers • custom outputs (?) • describe’s • …

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Rails ‘Best’ Practices :%s/Rails/Basecamp/g

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LET’S PRACTICE

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MODELS

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class User < ActiveRecord::Base has_many :posts ! def post_titles posts.map(&:title).join(', ') end end ! class Post < ActiveRecord::Base belongs_to :user end

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config/application.rb class Application < Rails::Application config.autoload_paths += %W(#{config.root}/app/ extensions/) end

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module PostsExtensions def post_titles names = posts.map(&:title) names.join(‘, ‘) end end class User < ActiveRecord::Base include PostsExtensions ! has_many :posts end

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Rails 4 - Concerns

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‘Concerned’ people suggest a different name!!!

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Please

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Controllers

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class UsersController < ApplicationController def index @users = search_users end ! private def search_users filters = [] unless params[:name].blank? filters << [ “name = ?”, params[:name] end ! unless params.[:last_name].blank? filters << [ “last_name = ?”, params[: last_name] end . . . User.where(filters) end end

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config/application.rb class Application < Rails::Application config.autoload_paths += %W(#{config.root}/app/extensions/ #{config.root}/lib/ ) end

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module UsersSearch def search_users filters = [] unless params[:name].blank? filters << [ “name = ?”, params[:name] end ! unless params.[:last_name].blank? filters << [ “last_name = ?”, params[: last_name] end . . . User.where(filters) end end

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class UsersController < ApplicationController ! include UsersSearch ! def index @users = search_users end end

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VIEWS

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Avoid if’s

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<% if @user.citizenship %> <%= some_helper @user.citizenship %> <% else %> <%= content_tag :span, t(‘not_related_citizenship’) %> <% end %>

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DECORATOR

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class PostsList def initialize(posts, user) @posts = posts @user = user end ! def build_posts posts_list = [] @posts do |post| posts_list << OpenStruct.new( title: post.title, description: post.description || ‘Sorry. No text here!’, author_name: @user.full_name ) end ! posts_list end

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Class PostsController < ApplicationController include PostsList ! def index @posts = PostList.new(Post.recent, current_user).build_posts end end

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<% @posts.each do |post| %> <%= post.title %> <%= post. description %> <%= post.author_name %> <% end %>

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OH, WAIT!!!!

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class User < ActiveRecord::Base include PostsExtensions include AvatarsExtensions include PaymentsExtensions include include include include include include include . . . end

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Editor’s problem

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module UsersExtensions def users users.map(&:name) end end

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module UsersExtensions def users users.map(&:name) end end

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class Registrations < ActiveRecord::Base include UsersExtensions ! has_many :users end > r = Registration.first > r.users => [ ‘you’, ‘are dumb’]

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Developer’s problem

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module UsersExtensions def users_name users.map(&:name) end end

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sum = any_hash.map { |k, v| k + v * 10 }

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sum = any_hash.map { |discount, price| discount + price * TAX }

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Bonus

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Just an example (another terrible one)...

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require 'spec_helper' ! describe User do it 'testing create user time' do 100.times { user = create(:user) user.should_not be_nil } end end

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$ time rspec spec/models/user_spec.rb . ! Finished in 6.67 seconds 1 example, 0 failures

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require 'spec_helper' ! describe User do it 'testing create user time' do 100.times { user = double(“User”) user.should_not be_nil } end end

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$ time rspec spec/models/user_spec.rb . ! Finished in 0.02927 seconds 1 example, 0 failures

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RUBY MODULES

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RAILS DEPENDENCY == 0

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#WINS

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FAST RAILS TESTS

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#WINS

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COMPOSITION over INHERITANCE

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#WINS

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CODE ORGANIZATION

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#WINS

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OBRIGADO! Merci! Thanks! Gracias! Cheers Mate! хࢎ