Dynamic keys for MongoMapper

dynamic_keys_example.rb

class AnalysisItem
  include MongoMapper::EmbeddedDocument

  key :name, String
  key :value, String
end

class Record
  include MongoMapper::Document  

  many :anaylsis_items

  def items
    @items ||= AnalysisItemProxy.new(analysis_items)
  end
end

class AnalysisItemProxy
  def intialize(items)
    items.each do |i|
      self.class.send(:define_method, i.name.downcase) { i.value }
      self.class.send(:define_method, "#{i.name.downcase}=") do |v|
        i.value = v
        i.save
      end
    end
  end
end

a1 = AnaylsisItem.create(:name => "Mongo", :value => "Sweet")
a2 = AnaylsisItem.create(:name => "Foo", :value => "Bar")
r = Record.new
r.analysis_items << a1
r.analysis_items << a2
r.save

r.items.mongo
#=> "Sweet"

r.items.foo
#=> "Bar"

r.items.foo = "Baz"
r.items.foo
#=> "Baz"