```ruby
# Schema: id, token, filename, content_type, metadata, byte_size, digest, created_at
class ActiveFile::Blob < ActiveRecord::Base
  self.table_name = "rails_active_file_blobs"

  store :metadata, coder: JSON
  has_secure_token

  class_attribute :verifier, default: -> { Rails.application.message_verifier('ActiveFile') }
  class_attribute :storage

  class << self
    def find_verified(signed_id)
      find(verifier.verify(signed_id))
    end

    def build_after_upload(data:, filename:, content_type: nil, metadata: nil)
      new.tap do |blob|
        blob.filename = name
        blob.content_type = Marcel::MimeType.for(data, name: name, declared_type: content_type)
        blob.data = data
      end
    end

    def create_after_upload!(data:, filename:, content_type: nil, metadata: nil)
      build_after_upload(data: data, filename: filename, content_type: content_type, metadata: metadata).tap(&:save!)
    end
  end

  def filename
    Filename.new(filename)
  end

  def delete
    storage.delete token
  end

  def purge
    delete
    destroy
  end

  def purge_later
    ActiveFile::PurgeJob.perform_later(self)
  end
end
```

Use key instead of token
user
```ruby
# Schema: id, key, filename, content_type, metadata, byte_size, digest, created_at
class ActiveFile::Blob < ActiveRecord::Base
  self.table_name = "rails_active_file_blobs"

  has_secure_token :key
  store :metadata, coder: JSON

  class_attribute :verifier, default: -> { Rails.application.message_verifier('ActiveFile') }
  class_attribute :storage

  class << self
    def find_verified(signed_id)
      find(verifier.verify(signed_id))
    end

    def build_after_upload(data:, filename:, content_type: nil, metadata: nil)
      new.tap do |blob|
        blob.filename = name
        blob.content_type = Marcel::MimeType.for(data, name: name, declared_type: content_type)
        blob.data = data
      end
    end

    def create_after_upload!(data:, filename:, content_type: nil, metadata: nil)
      build_after_upload(data: data, filename: filename, content_type: content_type, metadata: metadata).tap(&:save!)
    end
  end

  def filename
    Filename.new(filename)
  end

  def delete
    storage.delete token
  end

  def purge
    delete
    destroy
  end

  def purge_later
    ActiveFile::PurgeJob.perform_later(self)
  end
end
```
assistant