Agile Web Development with Rails, Edition 4

11.2 Iteration F2: Creating an AJAX-Based Cart

Add remote: true to the Add to Cart button

edit app/views/store/index.html.erb

<p id="notice"><%= notice %></p>

<h1>Your Pragmatic Catalog</h1>

<% cache @products do %>

  <% @products.each do |product| %>

    <% cache @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),

            remote: true %>

        </div>

      </div>

    <% end %>

  <% end %>

<% end %>

Enable a the controller to respond to js requests

edit app/controllers/line_items_controller.rb

  def create

    product = Product.find(params[:product_id])

    @line_item = @cart.add_product(product)

    respond_to do |format|

      if @line_item.save

        format.html { redirect_to store_index_url }

        format.js

        format.json { render action: 'show',

          status: :created, location: @line_item }

      else

        format.html { render action: 'new' }

        format.json { render json: @line_item.errors,

          status: :unprocessable_entity }

end

end

end

Use JavaScript to replace the cart with a new rendering

edit app/views/line_items/create.js.erb

$('#cart').html("<%=j render(@cart) %>");

rake test

rake aborted!

ActiveRecord::PendingMigrationError: Migrations are pending; run 'bin/rake db:migrate RAILS_ENV=test' to resolve this issue.

/home/rubys/git/rails/activerecord/lib/active_record/migration.rb:383:in `check_pending!'

/home/rubys/git/awdwr/edition4/work-225-40/depot/test/test_helper.rb:6:in `<class:TestCase>'

/home/rubys/git/awdwr/edition4/work-225-40/depot/test/test_helper.rb:5:in `<top (required)>'

/home/rubys/git/rails/activesupport/lib/active_support/dependencies.rb:229:in `require'

/home/rubys/git/rails/activesupport/lib/active_support/dependencies.rb:229:in `block in require'

/home/rubys/git/rails/activesupport/lib/active_support/dependencies.rb:214:in `load_dependency'

/home/rubys/git/rails/activesupport/lib/active_support/dependencies.rb:229:in `require'

/home/rubys/git/awdwr/edition4/work-225-40/depot/test/helpers/carts_helper_test.rb:1:in `<top (required)>'

/home/rubys/git/rails/activesupport/lib/active_support/dependencies.rb:229:in `require'

/home/rubys/git/rails/activesupport/lib/active_support/dependencies.rb:229:in `block in require'

/home/rubys/git/rails/activesupport/lib/active_support/dependencies.rb:214:in `load_dependency'

/home/rubys/git/rails/activesupport/lib/active_support/dependencies.rb:229:in `require'

/home/rubys/git/rails/railties/lib/rails/test_unit/sub_test_task.rb:73:in `block (3 levels) in define'

/home/rubys/git/rails/railties/lib/rails/test_unit/sub_test_task.rb:73:in `each'

/home/rubys/git/rails/railties/lib/rails/test_unit/sub_test_task.rb:73:in `block (2 levels) in define'

/home/rubys/git/rails/railties/lib/rails/test_unit/sub_test_task.rb:72:in `each'

/home/rubys/git/rails/railties/lib/rails/test_unit/sub_test_task.rb:72:in `block in define'

/home/rubys/git/rails/railties/lib/rails/test_unit/testing.rake:61:in `block in <top (required)>'

/home/rubys/.rvm/gems/ruby-2.2.5/gems/rake-11.2.1/exe/rake:27:in `<top (required)>'

/home/rubys/.rvm/gems/ruby-2.2.5/bin/ruby_executable_hooks:15:in `eval'

/home/rubys/.rvm/gems/ruby-2.2.5/bin/ruby_executable_hooks:15:in `<main>'

Tasks: TOP => test:run => test:units

(See full trace by running task with --trace)

Run options: --seed 40049

# Running tests:

Finished tests in 0.000718s, 0.0000 tests/s, 0.0000 assertions/s.

0 tests, 0 assertions, 0 failures, 0 errors, 0 skips