Conversion using marshaling and JSON load

setting.rb

# To store the application settings in a key value pair
# Type will store the data type so that the conversion can be
# done within the model before send

class Temp
  include DataMapper::Resource

  # Primary (serial) key
  property :id, Serial

  # Non-key columns
  property :name, String, required: true, unique: true
  property :value, Text
  property :conversion, ExtendedEnum[:json, :marshal], labels: ["json", "marshal"], index: true, default: :json

  # Hook
  before :save, :change_spaces_to_underscores

  def change_spaces_to_underscores
    self.name = self.name.downcase.gsub(' ','_')
  end


  class <<self

    # To retrieve data
    # Setting['organization_name']
    def [](key)
      data = self.first(name:key)
      return nil unless data
      if data.conversion == :json 
        JSON.load(data.value)['value']
      else
        Marshal::load(data.value)
      end
    end

    # To store data
    # Setting['organization_name']='support sages'
    def []=(key,object)
      class_names = [Symbol, Fixnum, String, Float]
      symbol = nil
      if object.class == Array then
        object.each do |item|
          raise "Invalid Data format stored to Model Hash" unless class_names.include?(item.class)
          symbol = true if item.class == Symbol
        end
        if symbol
          save_as_marshal key, object
        else
          save_as_json key, object
        end
      else
        raise "Invalid Data format stored to Model Hash" unless class_names.include?(object.class)
        return save_as_marshal(key, object) if object.class == Symbol
        save_as_json key, object
      end
    end

    private 
      def save_as_marshal key, object
          self.update_or_create({name:key}, {name:key, value:Marshal::dump(object), conversion: :marshal })
      end

      def save_as_json key, object
        json_data = Hash.new
        json_data[:value] = object
        self.update_or_create({name:key}, {name:key, value:json_data.to_json, conversion: :json})
      end

    protected
    def update_or_create(conditions = {}, attributes = {}, merger = true)
      begin
        if (row = first(conditions))
          row.update(attributes)
          row
        else
          create(merger ? (conditions.merge(attributes)) : attributes )
        end
      rescue
        false
      end
    end
  end

end