Nacre - Create class for resources, then subclass each resource

gistfile1.rb

module Nacre
  module API
    class ProductServiceResource # Abstract Class
      def self.api
          Nacre::Api.global_instance
      end

      def self.all
          search
      end

      def self.search(params = nil)
        results = []
        response = nil

        begin
          response = api.connection.get("#{search_url}#{params}")
        rescue
          raise "Error in response: #{response.body.inspect}\n#{api.inspect}"
        end

        hash = JSON.parse response.body
        hash['response']['results'].each do |result|
          model = self.new(result)
          results << model
        end
        return results
      end

    private

      def self.service_url
        "/product-service"
      end

      def self.url
        raise NotImplementedError.new("Child class must implement #{method_name}")
      end

      def self.search_url
        raise NotImplementedError.new("Child class must implement #{method_name}")
      end

    end
  end
end



module Nacre
    module API
        class Product < ProductServiceResource
            @@fields = [ :product_id, :product_name, :sku, :ean, :upc, :isbn,
                :stock_tracked, :sales_channel, :created, :updated,
                :bp_category, :product_group ]

            @@fields.each do |attr|
                attr_accessor attr
            end



            # is this a hash or array of fields??
            def initialize(hash = nil)
                load_values(hash)
                self  # is this necessary?
            end

            private

            def self.url
                service_url + "/product"
            end

            def self.search_url
                service_url + '/product-search'
            end

            def fields
                @@fields
            end

            #move this to the parent class
            def load_values(hash)
                self.fields.each do |field|
                    self.public_send "#{field.to_s}=", hash[field]
                end
            end
        end
    end
end