redis_object.rb

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

  attr_accessor :attributes, :id
  class_attribute :namespace
  class_attribute :redis

  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.exists key(id)

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

    def last_id
      redis.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.hmset key, *serializable_hash.flatten
    self
  end

  def clear
    redis.del key
  end

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

RedisObject.redis = REDIS_CONNECTION

temp_redis_object.rb

class TempRedisObject < RedisObject
  class_attribute :expires_in

  def persist
    super.tap do
      redis.expire key, expires_in
    end
  end
end

TempRedisObject.expires_in = 3.hours.to_i