hstorable.rb

module Hstorable
  extend ActiveSupport::Concern

  module ClassMethods
    private

    def hstore_accessor(hstore, *names)
      store_accessor hstore, names

      names.each do |name|
        hstore_predicate(hstore, name)
      end
    end

    def typed_hstore_accessor(hstore, names = {})
      names.each do |name, type|
        scope "has_#{name}",
              ->(value) { where("#{hstore} @> hstore(?, ?)", name, value.to_s) }

        case type
        when :float then float_hstore_accessor(hstore, name)
        when :integer then integer_hstore_accessor(hstore, name)
        when :boolean then boolean_hstore_accessor(hstore, name)
        else string_hstore_accessor(hstore, name)
        end
      end
    end

    def hstore_predicate(hstore, name)
      define_method("#{name}?") do
        read_store_attribute(hstore, name).present?
      end
    end

    def float_hstore_accessor(hstore, name)
      hstore_predicate(hstore, name)

      define_method(name) do
        (val = read_store_attribute(hstore, name)) && Float(val)
      end

      define_method("#{name}=") do |value|
        write_store_attribute(hstore, name, Float(value))
      end
    end

    def integer_hstore_accessor(hstore, name)
      hstore_predicate(hstore, name)

      define_method(name) do
        (val = read_store_attribute(hstore, name)) && Integer(val)
      end

      define_method("#{name}=") do |value|
        write_store_attribute(hstore, name, Integer(value))
      end
    end

    def boolean_hstore_accessor(hstore, name)
      hstore_predicate(hstore, name)

      define_method(name) do
        val = read_store_attribute(hstore, name)
        return val == 'true' if %w(true false).include?(val)
        val
      end

      define_method("#{name}=") do |value|
        write_store_attribute(hstore, name, value ? 'true' : 'false')
      end
    end

    def string_hstore_accessor(hstore, name)
      hstore_predicate(hstore, name)
      store_accessor(hstore, name)
    end
  end
end