put loading of dois for events into a concern. datacite/datacite#796

Gemfile

@@ -59,6 +59,7 @@ gem 'git', '~> 1.5'
 gem 'graphql', '~> 1.9', '>= 1.9.4'
 gem 'graphql-errors', '~> 0.3.0'
 gem 'graphql-batch', '~> 0.4.0'
+# gem 'batch-loader', '~> 1.4', '>= 1.4.1'
 gem 'graphql-cache', '~> 0.6.0', git: "https://github.com/stackshareio/graphql-cache"
 # gem 'ddtrace', '~> 0.23.3'
 

app/models/concerns/batch_loader_helper.rb

@@ -0,0 +1,12 @@
+module BatchLoaderHelper
+  extend ActiveSupport::Concern
+
+  class_methods do
+    def load_doi(object)
+      Doi.find_by_id(object.doi).results
+      # BatchLoader.for(object.doi).batch do |dois, loader|
+      #   Doi.find_by_id(object.doi).results.each { |doi| loader.call(doi.uid, doi) }
+      # end
+    end
+  end
+end

app/serializers/event_serializer.rb

@@ -1,13 +1,15 @@
 class EventSerializer
   include FastJsonapi::ObjectSerializer
+  include BatchLoaderHelper
+
   set_key_transform :camel_lower
   set_type :events
   set_id :uuid
 
   attributes :subj_id, :obj_id, :source_id, :relation_type_id, :total, :message_action, :source_token, :license, :occurred_at, :timestamp
 
   has_many :dois, record_type: :dois, serializer: DoiSerializer, id_method_name: :uid do |object|
-    Doi.find_by_id(object.doi).results
+    load_doi(object)
   end
 
   attribute :timestamp, &:updated_at