Agile Web Development with Rails, Edition 4

12.2 Iteration G2: Atom Feeds

Demonstrate various respond_to/format options, as well as "through" relations and basic authentication.

Define a "who_bought" member action

edit app/controllers/products_controller.rb

  def who_bought

    @product = Product.find(params[:id])

    respond_to do |format|

      format.atom

end

end

Define an Atom view (using the Atom builder)

edit app/views/products/who_bought.atom.builder

atom_feed do |feed|

  feed.title "Who bought #{@product.title}"

  latest_order = @product.orders.sort_by(&:updated_at).last

  feed.updated( latest_order && latest_order.updated_at )

  @product.orders.each do |order|

    feed.entry(order) do |entry|

      entry.title "Order #{order.id}"

      entry.summary type: 'xhtml' do |xhtml|

        xhtml.p "Shipped to #{order.address}"

        xhtml.table do

          xhtml.tr do

            xhtml.th 'Product'

            xhtml.th 'Quantity'

            xhtml.th 'Total Price'

end

          order.line_items.each do |item|

            xhtml.tr do

              xhtml.td item.product.title

              xhtml.td item.quantity

              xhtml.td number_to_currency item.total_price

end

end

          xhtml.tr do

            xhtml.th 'total', colspan: 2

            xhtml.th number_to_currency \

              order.line_items.map(&:total_price).sum

end

end

        xhtml.p "Paid by #{order.pay_type}"

end

      entry.author do |author|

        entry.name order.name

        entry.email order.email

end

end

end

end

Add "orders" to the Product class

edit app/models/product.rb

class Product < ActiveRecord::Base

  has_many :line_items

  has_many :orders, through: :line_items

  #...

end

Add to the routes

edit config/routes.rb

Depot::Application.routes.draw do

  resources :orders

  resources :line_items

  resources :carts

  get "store/index"

  resources :products do

    get :who_bought, on: :member

end

  # ...

  # You can have the root of your site routed with "root"

  # just remember to delete public/index.html.

  # root :to => 'welcome#index'

  root to: 'store#index', as: 'store'

  # ...

end

Fetch the Atom feed

curl --silent --user dave:secret http://localhost:3000/products/2/who_bought.atom

<?xml version="1.0" encoding="UTF-8"?>

<feed xml:lang="en-US" xmlns="http://www.w3.org/2005/Atom">

  <id>tag:localhost,2005:/products/2/who_bought</id>

  <link rel="alternate" type="text/html" href="http://localhost:3000"/>

  <link rel="self" type="application/atom+xml" href="http://localhost:3000/products/2/who_bought.atom"/>

  <title>Who bought CoffeeScript</title>

  <updated>2011-10-29T07:18:31Z</updated>

  <entry>

    <id>tag:localhost,2005:Order/1</id>

    <published>2011-10-29T07:18:31Z</published>

    <updated>2011-10-29T07:18:31Z</updated>

    <link rel="alternate" type="text/html" href="http://localhost:3000/orders/1"/>

    <title>Order 1</title>

    <summary type="xhtml">

      <div xmlns="http://www.w3.org/1999/xhtml">

        <p>Shipped to 123 Main St</p>

        <table>

          <tr>

            <th>Product</th>

            <th>Quantity</th>

            <th>Total Price</th>

          </tr>

          <tr>

            <td>CoffeeScript</td>

            <td>1</td>

            <td>$36.00</td>

          </tr>

          <tr>

            <th colspan="2">total</th>

            <th>$36.00</th>

          </tr>

        </table>

        <p>Paid by Check</p>

      </div>

    </summary>

    <author>

      <name>Dave Thomas</name>

      <email>customer@example.com</email>

    </author>

  </entry>

</feed>