gistfile1.rb

module NameIdCache
  def self.included(base)
    m = Module.new
    base.all.each do |record|
      m.__send__(:define_method, record.name) do
        record.record_id # using #record_id because OpenStruct is iffy about #id
      end
    end
    base.extend(m)
  end
end

# class DeliveryState < ActiveRecord::Base
#   include NameIdCache
# end

# For demonstration
class DeliveryState
  require "ostruct"
  
  def self.all
    [ # using #record_id because OpenStruct is iffy about #id
     { :record_id => 1, :name => "queued" },
     { :record_id => 2, :name => "downloading" },
    ].map { |r| OpenStruct.new(r) }
  end
  
  # included late because it has to be after #all, with AR this wouldn't be an issue
  include NameIdCache
end

puts DeliveryState.all.inspect
puts DeliveryState.queued.inspect
puts DeliveryState.downloading.inspect