From 12fdb129196643f8091383d7030c92c143f2de5e Mon Sep 17 00:00:00 2001
From: Martin Fenner <martin.fenner@datacite.org>
Date: Sun, 23 Jun 2019 19:19:49 +0200
Subject: [PATCH] put loading of dois for events into a concern.
 datacite/datacite#796

---
 Gemfile                                    |  1 +
 app/models/concerns/batch_loader_helper.rb | 12 ++++++++++++
 app/serializers/event_serializer.rb        |  4 +++-
 3 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 app/models/concerns/batch_loader_helper.rb

diff --git a/Gemfile b/Gemfile
index fc9b3138e..96fe46fbd 100644
--- a/Gemfile
+++ b/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'
 
diff --git a/app/models/concerns/batch_loader_helper.rb b/app/models/concerns/batch_loader_helper.rb
new file mode 100644
index 000000000..b7d46a1bb
--- /dev/null
+++ b/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
diff --git a/app/serializers/event_serializer.rb b/app/serializers/event_serializer.rb
index ccfc21456..f124c5bca 100644
--- a/app/serializers/event_serializer.rb
+++ b/app/serializers/event_serializer.rb
@@ -1,5 +1,7 @@
 class EventSerializer
   include FastJsonapi::ObjectSerializer
+  include BatchLoaderHelper
+
   set_key_transform :camel_lower
   set_type :events
   set_id :uuid
@@ -7,7 +9,7 @@ class EventSerializer
   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