redis_object.rb

# super-meta object persistence class to Redis
class RedisObject
  include ActiveModel::Serialization

  attr_accessor :attributes, :id
  cattr_writer :namespace

  class << self
    def namespace
      @namespace || self
    end

    def key(id)
      "#{namespace}:%s" % id
    end

    # specifically use the generic initializer to rebuild object
    def find(id)
      return nil unless REDIS_CONNECTION.exists key(id)

      new REDIS_CONNECTION.hgetall(key(id)).to_options
    end

    def last_id
      REDIS_CONNECTION.get key("NEXT_ID")
    end

    def last
      find last_id
    end
  end

  def initialize(params = {})
    @attributes = params
    @id = params[:id] || nil
  end

  def read_attribute_for_validation(key)
    @attributes[key]
  end
  alias :[] :read_attribute_for_validation

  def key(id=@id)
    self.class.key(id)
  end

  # store in redis
  def persist
    @attributes[:id] = @id = incr_key

    REDIS_CONNECTION.hmset key, *serializable_hash.flatten
    REDIS_CONNECTION.expire key, 3.hours.to_i
    self
  end

  def clear
    REDIS_CONNECTION.del key
  end

  private
  def incr_key
    REDIS_CONNECTION.incr key("NEXT_ID")
  end
end

Note, this is a temporary persistence. For our current usage, this object get discarded rather quickly as we use it to simplify passing data around in requests. But it doesn't have to be that way. Just remove the REDIS_CONNECTION.expire key, 3.hours.to_i