Workaround for dm-rest-adapter serialization to JSON with :field and foreign keys

custom_json_format.rb

# This is used temporarily, until serialization to :raw is done in dm-serializer
module DataMapper
  module Rest
    class CustomJsonFormat < DataMapperRest::Format::Json
      def string_representation(resource)
        model = resource.model
        hash  = {}
        
        hash = model.properties.reduce(hash) do |h, property|
          h.merge(property.field.to_sym => property.dump(property.get(resource)))
        end
        
        hash = model.relationships.reject{ |r| r.source_key == model.key }.reduce(hash) do |h, relationship|
          keys_hash = relationship.source_key.reduce({}) do |kh, key|
            kh.merge(key.field.to_sym => key.dump(key.get(resource)))
          end
          h.merge(keys_hash)
        end
        
        ActiveSupport::JSON.encode(hash)
      end
    end
  end
end