Polaroid Preview/Example.

organizer_fundraising_tips.rb

class Emails::OrganizerFundraisingTips
  include Polaroid.new(:rsvp_deadline, :meal_page_url)

  attr_reader :event

  def initialize(event)
    @event = event
  end


  def rsvp_deadline
    event.rsvp_confirmation_deadline.to_s :written_date
  end


  def meal_page_url
    event.public_url
  end

end

polaroid.rb

class Polaroid < Module

  def initialize(*messages)
    @messages = messages
    @polaroid_struct_class = ImmutableStruct.new(*messages)
    define_capture_method
    freeze
  end


  def included(base)
    base.const_set(:Snapshot, @polaroid_struct_class)
    base.extend(ClassMethods)
  end


private #######################################################################

  def define_capture_method
    messages = @messages

    define_method(:take_snapshot) do ||
      self.class::Snapshot.new(*(messages.map { |msg| self.send(msg) })).to_h
    end
  end

  module ClassMethods
    def build_from_snapshot(snapshot_hash)
      self::Snapshot.new(snapshot_hash)
    end
  end

end

somewhere_else.rb

email_viewmodel = Emails::OrganizerFundraisingTips.new(some_event)

# Capture the object' publicly-observable snapshot
snapshot = email_viewmodel.take_snapshot
# => {:rsvp_deadline=>"June 25, 2013", :meal_page_url=>"http://www.groupraise.com/events/1159"} 

# Do a lot of stuff.
# Maybe somewhere far away, maybe in a background job:

viewmodel_snapshot = Emails::OrganizerFundraisingTips.build_from_snapshot(snapshot)
# => #<struct Emails::OrganizerFundraisingTips::Snapshot rsvp_deadline="June 25, 2013", meal_page_url="http://www.groupraise.com/events/1159">