Question

I have a virtual shopping cart using sessions (sessions stored in the DB).
I add products to the cart using an AJAX call. This list is also sortable.
The problem I am having is updating the sort position of the products in the cart, given that the shopping cart is virtual. Can anyone help (specifically with the sortable_element :update action). Here is some of the code:

#cart.rb

class Cart
  attr_reader :items   

  def initialize
    @items = []
  end

  def add_product(product
    @items << CartItem.new(product)
  end
end

#cart_item.rb

class CartItem
  attr_reader :product

  def initialize(product)
    @product = product
  end

  def name
    @product.name
  end
end

#cart/index.html.erb

<div id="items">
  <%= render :partial => 'cart', :object => @cart %>
</div>

#cart/_cart.html.erb

<%= render :partial => 'cart_item', :collection => @cart.items %>
<%= sortable_element "items", :url => {:action => :update} %>

#cart/_cart_item.html.erb

<% content_tag_for :li, cart_item do %>
  <p><%= cart_item.name %></p>
<% end %>

#cart_controller.rb

def index
  find_cart
end

def update
  #???? how does I change the sort of @cart?
  render :nothing => true
end

def find_cart
  session[:cart] ||= @cart
end

Answer 1

look at this solution, I think it will do what you need

Sort a list of objects by using their attributes in Ruby