Agile Web Development with Rails, Edition 4

9.4 Playtime 9.2 Iteration D2: Connecting Products to Carts

9.3 Iteration D3: Adding a button

Now we connect the model objects we created to the controller and the view.

Add the button, connecting it to the Line Item Controller, passing the product id.

edit app/views/store/index.html.erb
<p id="notice"><%= notice %></p>
 
<h1>Your Pragmatic Catalog</h1>
 
<% cache ['store', Product.latest] do %>
  <% @products.each do |product| %>
    <% cache ['entry', product] do %>
      <div class="entry">
        <%= image_tag(product.image_url) %>
        <h3><%= product.title %></h3>
        <%= sanitize(product.description) %>
        <div class="price_line">
          <span class="price"><%= number_to_currency(product.price) %></span>
          <%= button_to 'Add to Cart', line_items_path(product_id: product) %>
        </div>
      </div>
    <% end %>
  <% end %>
<% end %>

Add a bit of style to make it show all on one line

edit app/assets/stylesheets/store.css.scss
    p, div.price_line {
      margin-left: 100px;
      margin-top: 0.5em; 
      margin-bottom: 0.8em; 
 
      form, div {
        display: inline;
      }
    }

See the button on the page

get /

Your Pragmatic Catalog

Cs

CoffeeScript

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Ruby

Programming Ruby 1.9 & 2.0

Ruby is the fastest growing and most exciting dynamic language out there. If you need to get working programs delivered fast, you should add Ruby to your toolbox.

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Rtp

Rails Test Prescriptions

Rails Test Prescriptions is a comprehensive guide to testing Rails applications, covering Test-Driven Development from both a theoretical perspective (why to test) and from a practical perspective (how to test effectively). It covers the core Rails testing tools and procedures for Rails 2 and Rails 3, and introduces popular add-ons, including Cucumber, Shoulda, Machinist, Mocha, and Rcov.

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Update the LineItem.new call to use set_cart and the product id. Additionally change the logic so that redirection upon success goes to the cart instead of the line item.

edit app/controllers/line_items_controller.rb
class LineItemsController < ApplicationController
  include CurrentCart
  before_action :set_cart, only: [:create]
  before_action :set_line_item, only: [:show, :edit, :update, :destroy]
 
  # GET /line_items
  #...
end
edit app/controllers/line_items_controller.rb
  def create
    product = Product.find(params[:product_id])
    @line_item = @cart.line_items.build(product: product)
 
    respond_to do |format|
      if @line_item.save
        format.html { redirect_to @line_item.cart,
          notice: 'Line item was successfully created.' }
        format.json { render :show,
          status: :created, location: @line_item }
      else
        format.html { render :new }
        format.json { render json: @line_item.errors,
          status: :unprocessable_entity }
      end
    end
  end

Try it once, and see that the output isn't very useful yet.

get /

Your Pragmatic Catalog

Cs

CoffeeScript

CoffeeScript is JavaScript done right. It provides all of JavaScript's functionality wrapped in a cleaner, more succinct syntax. In the first book on this exciting new language, CoffeeScript guru Trevor Burnham shows you how to hold onto all the power and flexibility of JavaScript while writing clearer, cleaner, and safer code.

$36.00
Ruby

Programming Ruby 1.9 & 2.0

Ruby is the fastest growing and most exciting dynamic language out there. If you need to get working programs delivered fast, you should add Ruby to your toolbox.

$49.95
Rtp

Rails Test Prescriptions

Rails Test Prescriptions is a comprehensive guide to testing Rails applications, covering Test-Driven Development from both a theoretical perspective (why to test) and from a practical perspective (how to test effectively). It covers the core Rails testing tools and procedures for Rails 2 and Rails 3, and introduces popular add-ons, including Cucumber, Shoulda, Machinist, Mocha, and Rcov.

$34.95
post /line_items?product_id=3
You are being redirected.
get http://localhost:3000/carts/1

Line item was successfully created.

Edit | Back

Update the template that shows the Cart.

edit app/views/carts/show.html.erb
<p id="notice"><%= notice %></p>
 
<h2>Your Pragmatic Cart</h2>
<ul>    
  <% @cart.line_items.each do |item| %>
    <li><%= item.product.title %></li>
  <% end %>
</ul>

Try it once again, and see that the products in the cart.

get /

Your Pragmatic Catalog

Cs

CoffeeScript

CoffeeScript is JavaScript done right. It provides all of JavaScript's functionality wrapped in a cleaner, more succinct syntax. In the first book on this exciting new language, CoffeeScript guru Trevor Burnham shows you how to hold onto all the power and flexibility of JavaScript while writing clearer, cleaner, and safer code.

$36.00
Ruby

Programming Ruby 1.9 & 2.0

Ruby is the fastest growing and most exciting dynamic language out there. If you need to get working programs delivered fast, you should add Ruby to your toolbox.

$49.95
Rtp

Rails Test Prescriptions

Rails Test Prescriptions is a comprehensive guide to testing Rails applications, covering Test-Driven Development from both a theoretical perspective (why to test) and from a practical perspective (how to test effectively). It covers the core Rails testing tools and procedures for Rails 2 and Rails 3, and introduces popular add-ons, including Cucumber, Shoulda, Machinist, Mocha, and Rcov.

$34.95
post /line_items?product_id=3
You are being redirected.
get http://localhost:3000/carts/1

Line item was successfully created.

Your Pragmatic Cart

  • Programming Ruby 1.9 & 2.0
  • Programming Ruby 1.9 & 2.0

9.4 Playtime 9.2 Iteration D2: Connecting Products to Carts