discourse/app/serializers/embeddable_host_serializer.rb

class EmbeddableHostSerializer < ApplicationSerializer

  TO_SERIALIZE = [:id, :host, :path_whitelist, :class_name, :category_id]

  attributes *TO_SERIALIZE

  TO_SERIALIZE.each do |attr|
    define_method(attr) { object.public_send(attr) }
  end

end