Caching database objects in memory

mem_store.rb

class MemStore
  def get(klass, id)
    Rails.cache.fetch("#{cachize(klass)}_#{id}") do
      klass.find(id)
    end
  end
  def remove(klass, id)
    Rails.cache.delete("#{cachize(klass)}_#{id}")
  end
  
  private
  def cachize(klass)
    klass.name.titleize.parameterize('_')
  end
end

module Cacheable
  extend ActiveSupport::Concern
  included do
    after_save :clear_cache
    after_destroy :clear_cache
  end
  private
  def clear_cache
    MemStore.remove(self.class, id)
  end
end
  
class DBObject
  include Mongoid::Document
  include Cacheable
end

obj = MemStore.get(DBObject, "523abc757b0059153f000091") # retrieved from db
obj = MemStore.get(DBObject, "523abc757b0059153f000091") # retrieved from memory

# change some obj attributes
obj.save # cache for obj cleared
obj = MemStore.get(DBObject, "523abc757b0059153f000091") # retrieved from db

obj.destroy # cache for obj cleared
obj = MemStore.get(DBObject, "523abc757b0059153f000091") # raies Mongoid::Errors::DocumentNotFound