gistfile1.txt

# This works alright, I wouldn't use it without testing first though.
module KeepsCachedRecords

  def self.included(base)
    base.extend ClassMethods
    class << base
      alias_method_chain :find_one, :cached_records
      alias_method_chain :find_some, :cached_records
      alias_method_chain :find_every, :cached_records
    end
  end

  module ClassMethods
    def find_every_with_cached_records(options = {}, &block)
      if use_cached_records?(options)
        cached_records
      else
        find_every_without_cached_records(options, &block)
      end
    end

    def find_one_with_cached_records(id, options = {}, &block)
      if use_cached_records?(options)
        cached_records.find {|record| id == record.id }
      else
        find_one_without_cached_records(id, options, &block)
      end
    end

    def find_some_with_cached_records(ids, options = {}, &block)
      if use_cached_records?(options)
        cached_records.select {|record| ids.include?(record.id) }
      else
        find_some_without_cached_records(ids, options, &block)
      end
    end

    protected

      # retrieve cached records. returns nil unless
      # keeps_cached_records is called in the class
      attr_accessor :cached_records

      def use_cached_records?(options)
        options.values.compact.blank? && !cached_records.blank?
      end

      def keeps_cached_records
        @cached_records = Array(all)
      end
  end
end

ActiveRecord::Base.send :include, KeepsCachedRecords