Question

I don’t understand 5th line in “line_items_controller.rb” :
I notice the code for Rails 3.1 don’t have such line while in code for Rails 3.2 it has such line.
From Java world, It’s hard to tell what kind of magic ruby used here 🙁
I was stuck in understanding Rails document.

e.g.
button_to has signiture button_to(name, options = {}, html_options = {})

But in the code, you can add on parameter like

<%= button_to 'Empty cart', @cart, :method => :delete, :confirm => 'Are you sure?' %>

I suppose @cart shouldn’t be there…

def create
    @cart = current_cart #this is a function method
    product = Product.find(params[:product_id])
    @line_item = @cart.add_product(product.id)
    @line_item.product = product

    respond_to do |format|
      if @line_item.save
        format.html { redirect_to @line_item.cart }
        format.json { render json: @line_item,
          status: :created, location: @line_item }
      else
        format.html { render action: "new" }
        format.json { render json: @line_item.errors,
          status: :unprocessable_entity }
      end
    end
end

Full source code for project here:
https://github.com/ilovejs/depot_i/blob/master/app/controllers/line_items_controller.rb

Answer 1

it seems like @cart.add_product(product.id)if to add a product to the @cart, and @line_item.product = product is also seems like doing the same thing

its little hard to tell without seeing the code of Cart model, however I think

removing the @line_item.product = product line should also work without a problem