Example of how an action which returns JSON response should look like in Rails.

orders_controller.rb

  def additemtoorder
    @result = Hash.new
    @result['status'] = true
    @result['error_messages'] = []
    @result['success_messages'] = []

    @order = Order.find(params[:id])
    @product = Product.find(params[:productid])

    @skus = ProductSku.where(:product_id=>@product.id).where(:purpose=>'primary')
    if @skus.length > 0
      @orderitem = OrderItem.new
      @orderitem.price = params[:price]
      @orderitem.qty = params[:qty]
      @orderitem.row_total = params[:price].to_f * params[:qty].to_f
      @orderitem.sku = @skus.first.sku
      @order.order_items << @orderitem

      if !@order.save
        @result['status'] &= false
        @result['error_messages'].push("Adding item to order failed")
      else
        @result['success_messages'].pushd("Added item to order successfully")
      end
    else
        @result['status'] &= false
        @result['error_messages'].push("Could not find any SKU with product id:"+@productid)
    end

    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @result }
    end
  end