Question

So I have a Carts model which has_many Items. When I’m on the Carts#show page I want to have a link to an action that removes an item from that cart, in other words something that will find the item and set its cart_id to nil.

What should I name this action? Which controller should it be in — CartsController or ItemsController? And lastly… how do I specify this route in my routes.rb (CODE PLEASE FOR THIS ONE)

Edit

I should be a bit more explicit: I don’t want to destroy an item when I remove it from a person’s cart. Each item is unique, and thus destroying it would destroy the listing… which is undesirable. Note that this also implies that this isn’t a HABTM relationship… items can’t belong to more than one cart.

Answer 1

Route:

resources :carts do
  resources :items
end

This generates the following routes:

cart_items GET    /carts/:cart_id/items(.:format)          items#index
               POST   /carts/:cart_id/items(.:format)          items#create
 new_cart_item GET    /carts/:cart_id/items/new(.:format)      items#new
edit_cart_item GET    /carts/:cart_id/items/:id/edit(.:format) items#edit
     cart_item GET    /carts/:cart_id/items/:id(.:format)      items#show
               PUT    /carts/:cart_id/items/:id(.:format)      items#update
               DELETE /carts/:cart_id/items/:id(.:format)      items#destroy
         carts GET    /carts(.:format)                         carts#index
               POST   /carts(.:format)                         carts#create
      new_cart GET    /carts/new(.:format)                     carts#new
     edit_cart GET    /carts/:id/edit(.:format)                carts#edit
          cart GET    /carts/:id(.:format)                     carts#show
               PUT    /carts/:id(.:format)                     carts#update
               DELETE /carts/:id(.:format)                     carts#destroy

So you’re really explicit in describing items – carts relationship.

You use your controllers like you normally would.

I don’t know why would you want to set the cart_id to nil instead of removing it, but this is how you would do it:

# in items_controller.rb

def destroy
    @item = Item.find(params[:id])
    @item.update_attributes(:cart_id => params[:cart_id])

    respond_to do |format|
      format.html { redirect_to items_url }
      format.json { head :no_content }
    end
end