requesting metrics with dois in REST

datacite/bracco#270

app/controllers/dois_controller.rb

@@ -135,6 +135,7 @@ def index
           render json: DoiSerializer.new(results, options).serialized_json, status: :ok
         end
       else
+
         states = total > 0 ? facet_by_key(response.aggregations.states.buckets) : nil
         resource_types = total > 0 ? facet_by_resource_type(response.aggregations.resource_types.buckets) : nil
         years = total > 0 ? facet_by_year(response.aggregations.years.buckets) : nil
@@ -155,6 +156,13 @@ def index
         subjects = total > 0 ? facet_by_key(response.aggregations.subjects.buckets) : nil
         certificates = total > 0 ? facet_by_key(response.aggregations.certificates.buckets) : nil
 
+        if params[:mix_in].present? 
+          dois_result = results.map { |result| result.dig(:_source, :doi) }.join(',') if total.positive?
+          citations = total.positive? ? EventsQuery.new.citations(dois_result) : nil
+          views = total.positive? ? EventsQuery.new.views(dois_result) : nil
+          downloads = total.positive? ? EventsQuery.new.downloads(dois_result) : nil
+        end
+
         respond_to do |format|
           format.json do
             options = {}
@@ -180,7 +188,10 @@ def index
               "linkChecksSchemaOrgId" => link_checks_schema_org_id,
               "linkChecksDcIdentifier" => link_checks_dc_identifier,
               "linkChecksCitationDoi" => link_checks_citation_doi,
-              subjects: subjects
+              subjects: subjects,
+              citations: citations,
+              views: views,
+              downloads: downloads,
             }.compact
 
             options[:links] = {

spec/requests/dois_spec.rb

@@ -104,6 +104,33 @@
     end
   end
 
+  describe 'GET /dois all with metrics', elasticsearch: true, vcr: true do
+    # let!(:dois) { create_list(:doi, 3, client: client, aasm_state: "findable") }
+    let!(:doi) { create(:doi, client: client,  aasm_state: "findable") }
+    let!(:events) { create_list(:event_for_datacite_related, 3, obj_id: doi.doi) }
+    let!(:views) { create_list(:event_for_datacite_usage, 2, obj_id: doi.doi) }
+
+    before do
+      Event.import
+      Doi.import
+      sleep 3
+    end
+
+    context 'when the record exists' do
+      it 'returns the Doi' do
+        get "/dois?mix-in=metrics", nil, headers
+
+
+        expect(last_response.status).to eq(200)
+        expect(json['data'].size).to eq(1)
+        expect(json.dig('meta', 'total')).to eq(1)
+        expect(json.dig('meta', 'citations').first.dig('count')).to eq(3)
+        expect(json.dig('meta', 'views').first.dig('count')).to be > 0
+        expect(json.dig('meta', 'downloads').first.dig('count')).to eq(0)
+      end
+    end
+  end
+
   describe 'state' do
     let(:doi_id) { "10.14454/4K3M-NYVG" }
     let(:xml) { Base64.strict_encode64(file_fixture('datacite.xml').read) }