Your application is not your framework

Talk given at CAS 2015 in Madrid

Transcript

1. Enrique Comba Riepenhausen YOUR APPLICATION IS NOT YOUR FRAMEWORK
2. Your application is not your framework @ecomba
3. Frameworks!
4. Why do we use them? • Convention • Configuration • Standardisation • Speed of development
5. Convention 40%–80% of the lifetime cost of a piece of software goes to maintenance.
6. Convention Hardly any software is maintained for its whole life by the original author.
7. Convention [Code] conventions improve the readability of the software, allowing engineers to understand new code more quickly and thoroughly.
8. Convention If you ship your source code as a product, you need to make sure it is as well packaged and clean as any other product you create.
9. Configuration Convention over "As a general rule we don't want to invent an enormous java.beans.everything class that people have to inherit from. Instead we'd like the JavaBeans runtimes to provide default behaviour for 'normal' objects, but to allow objects to override a given piece of default behaviour by inheriting from some specific java.beans.something interface."
10. Concrete examples Ruby on Rails (why? Because it’s easier to read)
11. Ruby on Rails • Model, View, Controller (MVC) • ActiveRecord • Convention over configuration
12. # app/models class Post < ActiveRecord::Base # Magic methods will be inherited by ActiveRecord::Base end
13. # app/controllers class BlogController < ApplicationController def list @posts = Post.all end def show @post = Post.find(params[:id]) end end
14. <!— app/views/blog —> <!— “list” —> <section class=“posts”> <% @posts.each do |post| %> <article class=“post” id=“<%= post.id %>”> <header> <h1> <%= link_to post_show_path(post), post.title %> </h1>
 </header> </article> <% end %> </section>
15. # app/controllers class BlogController < ApplicationController def list @posts = Post.all end def show @post = Post.find(params[:id]) end end
16. <!— app/views/blog —> <!— “show” —> <article class=“post” id=“<%= @post.id %>”> <header> <h1><%= @post.title %></h1>
 </header> <p><%= @post.body %></p> </article>
17. <!— app/views/blog —> <!— “show with comments” —> <article class=“post” id=“<%= @post.id %>”> <header> <h1><%= @post.title %></h1>
 </header> <p><%= @post.body %></p> <aside> <% @post.comments.each do |comment| %> … <% end %> </aside> </article>
18. # app/controllers class BlogController < ApplicationController def list @posts = Post.all end def show @post = Post.find(params[:id]) @comments = Post.comments end end
19. # app/controllers class BlogController < ApplicationController def list @posts = Post.all end def show @post = Post.find(params[:id]) end end
20. Our applications are more complex!
21. Big projects anyone?
23. Is there a better way?
24. # app/controllers class PurchaseOrderController < ApplicationController def show @contract = Contract.find(params[:contract_id]) @purchase_order = PurchaseOrder.find(params[:id]) end end
25. <!— app/views/purchase_order —> <article class=“purchase-order”> <header> <h1>Purchase Order No.: <%= @purchase_order.number %></h1>
 </header> <table> <th>…</th> <% @purchase_order.line_items.each do |item| %> … <% end %> </table> <aside> <!— extracting info about the @contract </aside> </article>
39. # app/controllers class PurchaseOrderController < ApplicationController def show @contract = Contract.find(params[:contract_id]) @purchase_order = PurchaseOrder.find(params[:id]) end end
40. # lib/orders module CasApp model Orders class PurchaseOrderForContract attr_reader :contact, :purchase_order def using(params) @contract = Contract.find(params[:contract_id]) @purchase_order = PurchaseOrder.find(params[:id]) end end end end
41. # app/controllers class PurchaseOrderController < ApplicationController def show order = CasApp::Orders::PurchaseOrderForContract.using(params) @contract = order.contract @purchase_order = order.purchase_order end end
42. # lib/orders module CasApp model Orders class PurchaseOrderPresenter def initialize(order) # … end end end end
43. # app/controllers class PurchaseOrderController < ApplicationController def show order = CasApp::Orders::PurchaseOrderForContract.using(params) @presenter = CasApp::Orders::PurchaseOrderPresenter.new(order) end end
44. Benefits • Logical separation of concerns • Speed of testing • Clarity in Application Purpose • Clarity in Application Structure
45. Your application is not your framework Questions?
46. Remember!