rails decorators

Implementing decorator pattern using draper

Transcript

1. Rails Decorators @mribica, Sarajevo Ruby Meetup
2. Problem sa MVC-om
4. <h1> <%= @product.title %> </h1> ! <label> Boja: </label> <% unless @product.color.empty? %> <span> <%= @product.color %> </span> <% else %> <span> Nema opcije </span> <% end %> ! <label> Size: </label> <% unless @product.size.empty? %> <span> <%= @product.size %> </span> <% else %> <span> Nema opcije </span> <% end %>
5. <h1> <%= @product.title %> </h1> ! <label> Boja: </label> <% unless @product.color.empty? %> <span> <%= @product.color %> </span> <% else %> <span> Nema opcije </span> <% end %> ! <label> Size: </label> <% unless @product.size.empty? %> <span> <%= @product.size %> </span> <% else %> <span> Nema opcije </span> <% end %>
6. <h1> <%= @product.title %> </h1> ! <label> Boja: </label> <% unless @product.color.empty? %> <span> <%= @product.color %> </span> <% else %> <span> Nema opcije </span> <% end %> ! <label> Size: </label> <% unless @product.size.empty? %> <span> <%= @product.size %> </span> <% else %> <span> Nema opcije </span> <% end %>
7. <p> <%= @product.retail_price %> </p> ! <p> <%= @product.price %> </p> ! <% if @product.retail_price %> <label> Usredite: </label> <p> <%= @product_retail_price - @product.price%> </p> <% end %> ! <% if @product.product_images.count > 0 %> <%= image_tag @product.product_images.first.image_url(:cover) %> <% else %> <%= image_tag ‘fallback/default_cover.png’%> </end>
8. <p> <%= @product.retail_price %> </p> ! <p> <%= @product.price %> </p> ! <% if @product.retail_price %> <label> Usredite: </label> <p> <%= @product_retail_price - @product.price%> </p> <% end %> ! <% if @product.product_images.count > 0 %> <%= image_tag @product.product_images.first.image_url(:cover) %> <% else %> <%= image_tag ‘fallback/default_cover.png’%> </end>
9. <p> <%= @product.retail_price %> </p> ! <p> <%= @product.price %> </p> ! <% if @product.retail_price %> <label> Ustedite: </label> <p> <%= @product_retail_price - @product.price%> </p> <% end %> ! <% if @product.product_images.count > 0 %> <%= image_tag @product.product_images.first.image_url(:cover) %> <% else %> <%= image_tag ‘fallback/default_cover.png’%> </end>
10. <p> <%= @product.retail_price %> </p> ! <p> <%= @product.price %> </p> ! <% if @product.retail_price %> <label> Ustedite: </label> <p> <%= @product_retail_price - @product.price%> </p> <% end %> ! <% if @product.product_images.count > 0 %> <%= image_tag @product.product_images.first.image_url(:cover) %> <% else %> <%= image_tag ‘fallback/default_cover.png’%> </end>
11. <h1> <%= @product.title %> </h1> ! <label> Boja: </label> <% unless @product.color.empty? %> <span> <%= @product.color %> </span> <% else %> <span> Nema opcije </span> <% end %> ! <label> Size: </label> <% unless @product.size.empty? %> <span> <%= @product.size %> </span> <% else %> <span> Nema opcije </span> <% end %> ! <p> <%= @product.retail_price %> </p> ! <p> <%= @product.price %> </p> ! <% if @product.retail_price %> <label> Usredite: </label> <p> <%= @product_retail_price - @product.price%> </p> <% end %> ! <% if @product.product_images.count > 0 %> <%= image_tag @product.product_images.first.image_url(:cover) %> <% else %> <%= image_tag ‘fallback/default_cover.png’%> </end>
12. #app/helpers/product_helper.rb ! module ProductHelper def cover_image(product) first_image = product.product_images.try(:first) ! if first_image h.content_tag :img, first_image.url(:cover) else h.content_tag :img, ‘fallback/default_cover.png’ end end end ! #app/views/products/show.html.erb ! <%= cover_image(@product) %>
13. Model View Controller
14. Model View Controller Decorator
15. gem ‘draper’
16. Generisanje dekoratora $ rails g decorator Product # app/decorators/product_decorator.rb
17. # app/decorators/product_decorator.rb ! class ProductDecorator < Draper::Decorator def size unless object.size.empty? h.content_tag :span, object.size else h.content_tag :span, ‘Nema opcije za velicinu’ end end end Implemetacija
18. # app/controllers/products_controller.rb ! class ProductsController < ApplicationController decorate_assigned :product ! def show @product = Product.find(params[:id]) end end Dekorisanje
19. # app/views/product/show.html.erb ! <%= product.size %> Koristenje Dekoratora
20. # app/decorators/product_decorator.rb ! class ProductDecorator < Draper::Decorator … def color unless object.color.empty? h.content_tag :span, object.color else h.content_tag :span, ‘Nema opcije za boju’ end end end
21. # app/decorators/product_decorator.rb ! class ProductDecorator < Draper::Decorator … def cover_image first_image = object.images.try(:first) if first_image h.image_tag first_image.image_url(:cover) else h.image_tag ‘fallback/cover_image.png’ end end end
22. # app/decorators/product_decorator.rb ! class ProductDecorator < Draper::Decorator … ! def discount if object.retail_price h.content_tag :span, object.retail_price - object.price end end end
23. <h1> <%= @product.title %> </h1> ! <label> Boja: </label> <% unless @product.color.empty? %> <span> <%= @product.color %> </span> <% else %> <span> Nema opcije </span> <% end %> ! <label> Size: </label> <% unless @product.size.empty? %> <span> <%= @product.size %> </span> <% else %> <span> Nema opcije </span> <% end %> ! <p> <%= @product.retail_price %> </p> ! <p> <%= @product.price %> </p> ! <% if @product.retail_price %> <label> Usredite: </label> <p> <%= @product_retail_price - @product.price%> </p> <% end %> ! <% if @product.product_images.count > 0 %> <%= image_tag @product.product_images.first.image_url(:cover) %> <% else %> <%= image_tag ‘fallback/default_cover.png’%> </end>
24. <h1> <%= @product.title %> </h1> ! <label> Boja: </label> <%= product.color %> ! <label> Size: </label> <%= product.size %> ! <p> <%= @product.retail_price %> </p> <p> <%= @product.price %> </p> ! <%= product.discount %> <%= product.cover_image %>
25. Pitanja?