Patterns Falacy v2

My second talk about 'patterns' on rails community. Some of them should be updated to avoid scale problems and others stuffs.

Transcript

1. PATTERNS FALACY! Luciano Sousa http://lucianosousa.net twitter: @lucianosousa github: lucianosousa v2
2. #WHOAMI?
4. #War Feelings
5. SOCITRIP.COM
6. DISCLAIMER
7. Focus on ideas, not examples Think about what you are you doing with your apps Try solve your problems out of the box
8. A BRIEF HISTORY OF TIME
9. MVC
10. MVC FRAMEWORK BASED RAILS
11. 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
13. LIVE EXAMPLE
14. ‘PATTERNS’
15. Oh, wait... Patterns?
16. like...
17. R.I.P. OBSERVERS
18. 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
19. SCAFFOLD
20. Sloth
21. and... not least
22. CoffeeScript
23. Bad, bad server. No Donut for you
24. http://codon.com/the-dhh-problem
25. RAILS & RAILS 4
28. TestUnit x RSpec
29. RSPEC • pending examples <3 • matchers • custom outputs (?) • describe’s • …
30. Rails ‘Best’ Practices :%s/Rails/Basecamp/g
31. LET’S PRACTICE
32. MODELS
33. class User < ActiveRecord::Base has_many :posts ! def post_titles posts.map(&:title).join(', ') end end ! class Post < ActiveRecord::Base belongs_to :user end
34. config/application.rb class Application < Rails::Application config.autoload_paths += %W(#{config.root}/app/ extensions/) end
35. module PostsExtensions def post_titles names = posts.map(&:title) names.join(‘, ‘) end end class User < ActiveRecord::Base include PostsExtensions ! has_many :posts end
36. Rails 4 - Concerns
37. ‘Concerned’ people suggest a different name!!!
38. Please
39. Controllers
40. 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
41. config/application.rb class Application < Rails::Application config.autoload_paths += %W(#{config.root}/app/extensions/ #{config.root}/lib/ ) end
42. 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
43. class UsersController < ApplicationController ! include UsersSearch ! def index @users = search_users end end
44. VIEWS
45. Avoid if’s
46. <% if @user.citizenship %> <%= some_helper @user.citizenship %> <% else %> <%= content_tag :span, t(‘not_related_citizenship’) %> <% end %>
47. DECORATOR
48. 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
49. Class PostsController < ApplicationController include PostsList ! def index @posts = PostList.new(Post.recent, current_user).build_posts end end
50. <% @posts.each do |post| %> <%= post.title %> <%= post. description %> <%= post.author_name %> <% end %>
51. OH, WAIT!!!!
52. class User < ActiveRecord::Base include PostsExtensions include AvatarsExtensions include PaymentsExtensions include include include include include include include . . . end
53. Editor’s problem
54. module UsersExtensions def users users.map(&:name) end end
55. module UsersExtensions def users users.map(&:name) end end
56. class Registrations < ActiveRecord::Base include UsersExtensions ! has_many :users end > r = Registration.first > r.users => [ ‘you’, ‘are dumb’]
57. Developer’s problem
58. module UsersExtensions def users_name users.map(&:name) end end
59. sum = any_hash.map { |k, v| k + v * 10 }
60. sum = any_hash.map { |discount, price| discount + price * TAX }
61. Bonus
62. Just an example (another terrible one)...
63. require 'spec_helper' ! describe User do it 'testing create user time' do 100.times { user = create(:user) user.should_not be_nil } end end
64. $ time rspec spec/models/user_spec.rb . ! Finished in 6.67 seconds 1 example, 0 failures
65. require 'spec_helper' ! describe User do it 'testing create user time' do 100.times { user = double(“User”) user.should_not be_nil } end end
66. $ time rspec spec/models/user_spec.rb . ! Finished in 0.02927 seconds 1 example, 0 failures
67. RUBY MODULES
68. RAILS DEPENDENCY == 0
69. #WINS
70. FAST RAILS TESTS
71. #WINS
72. COMPOSITION over INHERITANCE
73. #WINS
74. CODE ORGANIZATION
75. #WINS
77. OBRIGADO! Merci! Thanks! Gracias! Cheers Mate! хࢎ