Paperclip stored Redis

paperclip_radis.rb

# @see https://gist.github.com/basgys/5712426#gistcomment-1274422
class UploadFile
  include ActiveModel::Model
  include Paperclip::Glue

  # Paperclip required callbacks
  define_model_callbacks :save, only: [:after]
  define_model_callbacks :commit, only: [:after]
  define_model_callbacks :destroy, only: [:before, :after]

  def self.attributes
    [
      :id,
      :file_file_name,
      :file_content_type,
      :file_file_size,
      :file_updated_at,
      :file_fingerprint,
      :file_meta,
    ]
  end

  attr_accessor *attributes

  FinguerPrintHashFunc = Digest::SHA256

  has_attached_file :file,
    adapter_options: { hash_digest: FinguerPrintHashFunc }

  do_not_validate_attachment_file_type :file

  class << self
    def redis_key(sub_key)
      sub_key = sub_key.join(':') if sub_key.is_a? Array
      "#{Rails.application.class.parent_name}:#{name}:#{sub_key}"
    end

    def redis
      Redis.current
    end

    def redis_record_key(id)
      redis_key [:record, id]
    end

    def find(id)
      id = redis_record_key(id)
      raise ActiveRecord::RecordNotFound, id unless redis.exists(id)
      result = redis.hmget(id, attributes)
      result = result.map &JSON.method(:load)
      result = attributes.zip result
      result = Hash[result]
      new(result)
    end
  end

  def redis_record_key
    self.class.redis_record_key(id)
  end

  def attributes
    self.class.attributes.reduce({}) do |memo, attr|
      memo[attr.to_s] = public_send(attr)
      memo
    end
  end

  def file_updated_at=(value)
    @file_updated_at = Time.zone.parse(value.to_s)
  end

  def inspect
    attrs = attributes.map { |(k, v)| [k, v.inspect].join(': ') }.join(",\n ")
    "#<#{self.class.name}:#{object_id} \n #{attrs}>"
  end

  def new_record?
    id.nil?
  end

  def save
    return false unless valid?

    run_callbacks :save do
      self.id = SecureRandom.uuid if new_record?
      attr = attributes.map do |(key, value)|
        [key, JSON.dump(value)]
      end
      self.class.redis.hmset(redis_record_key, *attr.flatten)
      self.class.redis.expire(redis_record_key, 10)
    end

    run_callbacks :commit

    true
  end

  def save!
    validate!
    save
    self
  end

  def destroy
    run_callbacks :destroy do
      self.class.redis.del self.redis_record_key
    end
    run_callbacks :commit
  end
end