Agile Web Development with Rails, Edition 4

Agile Web Development with Rails, Edition 4

12.2 Iteration G2: Atom Feeds 11.6 Iteration F6: Testing AJAX changes

12.1 Iteration G1: Capturing an Order

Create a model to contain orders

rails generate scaffold Order name:string address:text email:string pay_type:string
      invoke  active_record
      create    db/migrate/20120629163306_create_orders.rb
      create    app/models/order.rb
      invoke    test_unit
      create      test/unit/order_test.rb
      create      test/fixtures/orders.yml
       route  resources :orders
      invoke  scaffold_controller
      create    app/controllers/orders_controller.rb
      invoke    erb
      create      app/views/orders
      create      app/views/orders/index.html.erb
      create      app/views/orders/edit.html.erb
      create      app/views/orders/show.html.erb
      create      app/views/orders/new.html.erb
      create      app/views/orders/_form.html.erb
      invoke    test_unit
      create      test/functional/orders_controller_test.rb
      invoke    helper
      create      app/helpers/orders_helper.rb
      invoke      test_unit
      create        test/unit/helpers/orders_helper_test.rb
      invoke  stylesheets
   identical    public/stylesheets/scaffold.css

Create a migration to add an order_id column to line_items

rails generate migration add_order_id_to_line_item order_id:integer
      invoke  active_record
      create    db/migrate/20120629163309_add_order_id_to_line_item.rb

Apply both migrations

rake db:migrate
mv 20120629163306_create_orders.rb 20110711000007_create_orders.rb
mv 20120629163309_add_order_id_to_line_item.rb 20110711000008_add_order_id_to_line_item.rb
==  CreateOrders: migrating ===================================================
-- create_table(:orders)
   -> 0.0020s
==  CreateOrders: migrated (0.0021s) ==========================================
 
==  AddOrderIdToLineItem: migrating ===========================================
-- add_column(:line_items, :order_id, :integer)
   -> 0.0011s
==  AddOrderIdToLineItem: migrated (0.0012s) ==================================
 

Add a Checkout button to the cart

edit app/views/carts/_cart.html.erb
<div class="cart_title">Your Cart</div>
<table>
  <%= render(cart.line_items) %>
 
  <tr class="total_line">
    <td colspan="2">Total</td>
    <td class="total_cell"><%= number_to_currency(cart.total_price) %></td>
  </tr>
 
</table>
 
<%= button_to "Checkout", new_order_path, :method => :get %>
<%= button_to 'Empty cart', cart, :method => :delete,
    :confirm => 'Are you sure?' %>

Return a notice when checking out an empty cart

edit app/controllers/orders_controller.rb
  def new
    @cart = current_cart
    if @cart.line_items.empty?
      redirect_to store_url, :notice => "Your cart is empty"
      return
    end
 
    @order = Order.new
 
    respond_to do |format|
      format.html # new.html.erb
      format.xml  { render :xml => @order }
    end
  end

Modify tests to ensure that there is an item in the cart

edit test/functional/orders_controller_test.rb
  test "requires item in cart" do
    get :new
    assert_redirected_to store_path
    assert_equal flash[:notice], 'Your cart is empty'
  end
 
  test "should get new" do
    item = LineItem.new
    item.build_cart
    item.product = products(:ruby)
    item.save!
    session[:cart_id] = item.cart.id
 
    get :new
    assert_response :success
  end

Modify the template for new orders

edit app/views/orders/new.html.erb
<div class="depot_form">
  <fieldset>
    <legend>Please Enter Your Details</legend>
    <%= render 'form' %>
  </fieldset>
</div>

Modify the partial used by the template

edit app/views/orders/_form.html.erb
<%= form_for(@order) do |f| %>
  <% if @order.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@order.errors.count, "error") %>
      prohibited this order from being saved:</h2>
 
      <ul>
      <% @order.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
 
  <div class="field">
    <%= f.label :name %><br />
    <%= f.text_field :name, :size => 40 %>
  </div>
  <div class="field">
    <%= f.label :address %><br />
    <%= f.text_area :address, :rows => 3, :cols => 40 %>
  </div>
  <div class="field">
    <%= f.label :email %><br />
    <%= f.email_field :email, :size => 40 %>
  </div>
  <div class="field">
    <%= f.label :pay_type %><br />
    <%= f.select :pay_type, Order::PAYMENT_TYPES,
                  :prompt => 'Select a payment method' %>
  </div>
  <div class="actions">
    <%= f.submit 'Place Order' %>
  </div>
<% end %>

Add payment types to the order

edit app/models/order.rb
class Order < ActiveRecord::Base
  PAYMENT_TYPES = [ "Check", "Credit card", "Purchase order" ]
end

Add some CSS

edit public/stylesheets/depot.css
/* Styles for order form */
 
.depot_form fieldset {
  background: #efe;
}
 
.depot_form legend {
  color: #dfd;
  background: #141;
  font-family: sans-serif;
  padding: 0.2em 1em;
}
 
.depot_form label {
  width: 5em;
  float: left;
  text-align: right;
  padding-top: 0.2em;
  margin-right: 0.1em;
  display: block;
}
 
.depot_form select, .depot_form textarea, .depot_form input {
  margin-left: 0.5em;
}
 
.depot_form .submit {
  margin-left: 4em;
}
 
.depot_form div {
  margin: 0.5em 0;
}

Validate name and pay_type

edit app/models/order.rb
class Order < ActiveRecord::Base
  # ...
  validates :name, :address, :email, :presence => true
  validates :pay_type, :inclusion => PAYMENT_TYPES
end

Update the test data in the orders fixture

edit test/fixtures/orders.yml
# Read about fixtures at http://ar.rubyonrails.org/classes/Fixtures.html
 
one:
  name: Dave Thomas
  address: MyText
  email: dave@example.org
  pay_type: Check
 
two:
  name: MyString
  address: MyText
  email: MyString
  pay_type: MyString

Move a line item from a cart to an order

edit test/fixtures/line_items.yml
# Read about fixtures at http://ar.rubyonrails.org/classes/Fixtures.html
 
one:
  product: ruby
  order: one
 
two:
  product: ruby
  cart: one

Define a relationship from the line item to the order

edit app/models/line_item.rb
class LineItem < ActiveRecord::Base
  belongs_to :order
  belongs_to :product
  belongs_to :cart
 
  def total_price
    product.price * quantity
  end
end

Define a relationship from the order to the line item

edit app/models/order.rb
class Order < ActiveRecord::Base
  has_many :line_items, :dependent => :destroy
  # ...
end

Add line item to order, destroy cart, and redisplay catalog page

edit app/controllers/orders_controller.rb
  def create
    @order = Order.new(params[:order])
    @order.add_line_items_from_cart(current_cart)
 
    respond_to do |format|
      if @order.save
        Cart.destroy(session[:cart_id])
        session[:cart_id] = nil
        format.html { redirect_to(store_url, :notice => 
          'Thank you for your order.') }
        format.xml  { render :xml => @order, :status => :created,
          :location => @order }
      else
        @cart = current_cart
        format.html { render :action => "new" }
        format.xml  { render :xml => @order.errors,
          :status => :unprocessable_entity }
      end
    end
  end

Implement add_line_items_from_cart

edit app/models/order.rb
class Order < ActiveRecord::Base
  # ...
  def add_line_items_from_cart(cart)
    cart.line_items.each do |item|
      item.cart_id = nil
      line_items << item
    end
  end
end

Modify the test to reflect the new redirect

edit test/functional/orders_controller_test.rb
  test "should create order" do
    assert_difference('Order.count') do
      post :create, :order => @order.attributes
    end
 
    assert_redirected_to store_path
  end

take a look at the validation errors

get /orders/new
Your Cart
CoffeeScript $36.00
Total $36.00
Please Enter Your Details




post /orders
Your Cart
CoffeeScript $36.00
Total $36.00
Please Enter Your Details

4 errors prohibited this order from being saved:

  • Name can't be blank
  • Address can't be blank
  • Email can't be blank
  • Pay type is not included in the list




process an order

get /orders/new
Your Cart
CoffeeScript $36.00
Total $36.00
Please Enter Your Details




post /orders
You are being redirected.
get http://localhost:3000/

Thank you for your order.

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look at the underlying database

sqlite3> select * from orders
        id = 1
      name = Dave Thomas
   address = 123 Main St
     email = customer@example.com
  pay_type = Check
created_at = 2012-06-29 16:33:20.129171
updated_at = 2012-06-29 16:33:20.129171
sqlite3> select * from line_items
        id = 10
product_id = 2
   cart_id = 
created_at = 2012-06-29 16:32:51.217550
updated_at = 2012-06-29 16:33:20.132978
  quantity = 1
     price = 36
  order_id = 1

hide the notice when adding items to the cart

edit app/views/line_items/create.js.rjs
page.select("#notice").each { |notice| notice.hide }
 
page.replace_html('cart', render(@cart))
 
page[:cart].visual_effect :blind_down if @cart.total_items == 1
 
page[:current_item].visual_effect :highlight,
                                  :startcolor => "#88ff88",
                                  :endcolor => "#114411"

12.2 Iteration G2: Atom Feeds 11.6 Iteration F6: Testing AJAX changes