hstore_mapping.rb

module Models::HstoreMap

  def convert_hstore_to(to_type, *methods)
    methods.each do |meth|
      alias_method :"old_#{meth}", meth
      define_method meth do
        send(:"old_#{meth}").try(to_type)
      end
    end
  end

  def convert_hstore_to_decimal(*methods)
    convert_hstore_to(:to_d, *methods)
  end

  def convert_hstore_to_time(*methods)
    convert_hstore_to(:to_time, *methods)
  end

  def convert_hstore_to_timezone(*methods)
    methods.each do |meth|
      alias_method :"old_#{meth}", meth
      class_eval <<-CODE, __FILE__, __LINE__ + 1
        def #{meth}
          return old_#{meth}  if old_#{meth}.is_a?(Time)
          Time.zone.parse(old_#{meth})
        rescue
          nil
        end
      CODE
    end
  end

  def convert_hstore_to_date(*methods)
    convert_hstore_to(:to_date, *methods)
  end

  def convert_hstore_to_integer(*methods)
    convert_hstore_to(:to_i, *methods)
  end

  def convert_hstore_to_boolean(*methods)
    methods.each do |meth|
      alias_method :"old_#{meth}", meth
      define_method :"#{meth}" do
        if %w{true false}.include? send(:"old_#{meth}")
          send(:"old_#{meth}") == "true" ? true : false
        else
          send(:"old_#{meth}")
        end
      end

      define_method :"#{meth}?" do
        !!send(meth)
      end
    end
  end
end


class Expense < ActiveRecord::Base

  # Store
  EXTRA_COLUMNS = %i(bill_number gross_total original_total balance_inventory nuller_datetime null_reason approver_datetime delivered discounted devolution no_inventory).freeze
  store_accessor( *([:extras] + EXTRA_COLUMNS))

  # Extra methods defined for Hstore
  extend Models::HstoreMap
  convert_hstore_to_boolean :devolution, :delivered, :discounted, :no_inventory
  convert_hstore_to_decimal :gross_total, :original_total, :balance_inventory
  convert_hstore_to_timezone :nuller_datetime, :approver_datetime
end