Support RDF/XML and Turtle content negotiation; fix wildcard Accept 500

app/controllers/index_controller.rb

@@ -14,7 +14,7 @@ def show
     respond_to do |format|
       format.html do
         # forward to URL registered in handle system for no content negotiation
-        redirect_to doi.url, status: :see_other
+        redirect_to doi.url, status: :see_other, allow_other_host: true
       end
       format.citation do
         # extract optional style and locale from header
@@ -37,8 +37,10 @@ def show
         :datacite,
         :datacite_json,
         :jats,
+        :rdf_xml,
         :ris,
         :schema_org,
+        :turtle,
       ) { render request.format.to_sym => doi }
       header = %w[
         doi

app/models/doi.rb

@@ -2826,6 +2826,29 @@ def handle_resource_type(types)
     end
   end
 
+  # Ensure Bolognese metadata is populated from stored DataCite XML before
+  # calling Bolognese RDF writers. This is local-only (no network calls).
+  def ensure_bolognese_meta!
+    return meta if meta.present?
+    return meta if xml.blank?
+
+    @meta = parse_xml(xml, doi: doi)
+  end
+
+  def rdf_xml
+    ensure_bolognese_meta!
+    raise ActionController::UnknownFormat, "RDF representation is not available for this DOI" if graph.nil?
+
+    super
+  end
+
+  def turtle
+    ensure_bolognese_meta!
+    raise ActionController::UnknownFormat, "RDF representation is not available for this DOI" if graph.nil?
+
+    super
+  end
+
   private
     def update_publisher_from_hash
       symbolized_publisher_hash = publisher_before_type_cast.symbolize_keys

config/initializers/mime_types.rb

@@ -35,6 +35,8 @@
 Mime::Type.register "application/x-bibtex", :bibtex
 Mime::Type.register "application/x-research-info-systems", :ris
 Mime::Type.register "text/x-bibliography", :citation
+Mime::Type.register "application/rdf+xml", :rdf_xml
+Mime::Type.register "text/turtle", :turtle, %w[application/x-turtle]
 
 # register renderers for these Mime types
 # :citation and :datacite is handled differently
@@ -83,3 +85,11 @@
 ActionController::Renderers.add :csv do |obj, options|
   options[:header].to_csv + Array.wrap(obj).map { |o| o.send("csv") }.join("")
 end
+
+ActionController::Renderers.add :rdf_xml do |obj, _options|
+  Array.wrap(obj).map { |o| o.rdf_xml }.join("\n")
+end
+
+ActionController::Renderers.add :turtle do |obj, _options|
+  Array.wrap(obj).map { |o| o.turtle }.join("\n")
+end

config/routes.rb

@@ -53,6 +53,12 @@
       to: "index#show", constraints: { id: /.+/ }, defaults: { format: :bibtex }
   get "/application/x-research-info-systems/:id",
       to: "index#show", constraints: { id: /.+/ }, defaults: { format: :ris }
+  get "/application/rdf+xml/:id",
+      to: "index#show", constraints: { id: /.+/ }, defaults: { format: :rdf_xml }
+  get "/application/x-turtle/:id",
+      to: "index#show", constraints: { id: /.+/ }, defaults: { format: :turtle }
+  get "/text/turtle/:id",
+      to: "index#show", constraints: { id: /.+/ }, defaults: { format: :turtle }
   get "/text/csv/:id",
       to: "index#show", constraints: { id: /.+/ }, defaults: { format: :csv }
   get "/text/x-bibliography/:id",

spec/factories/doi.rb

@@ -27,6 +27,11 @@
         "lang": "en",
       }
     end
+
+    trait :with_datacite_xml do
+      xml { file_fixture("datacite.xml").read }
+    end
+
     creators do
       [
         {

spec/requests/index_spec.rb

@@ -4,6 +4,7 @@
 
 describe IndexController, type: :request do
   let(:doi) { create(:doi, aasm_state: "findable") }
+  let(:doi_with_xml) { create(:doi, :with_datacite_xml, aasm_state: "findable") }
 
   describe "content_negotation" do
     context "application/vnd.jats+xml" do
@@ -337,5 +338,102 @@
         expect(last_response.headers["Location"]).to eq(doi.url)
       end
     end
+
+    context "wildcard Accept: */*" do
+      it "redirects without 500" do
+        get "/#{doi.doi}", nil, { "HTTP_ACCEPT" => "*/*" }
+
+        expect(last_response.status).not_to eq(500)
+        expect([200, 302, 303]).to include(last_response.status)
+      end
+    end
+
+    context "application/rdf+xml" do
+      it "returns the Doi as RDF/XML" do
+        get "/#{doi_with_xml.doi}", nil, { "HTTP_ACCEPT" => "application/rdf+xml" }
+
+        expect(last_response.status).to eq(200)
+        expect(last_response.headers["Content-Type"]).to include("application/rdf+xml")
+        expect(last_response.body).to include("rdf:RDF")
+      end
+
+      it "returns 406 when RDF representation is not available" do
+        get "/#{doi.doi}", nil, { "HTTP_ACCEPT" => "application/rdf+xml" }
+
+        expect(last_response.status).to eq(406)
+        expect(json["errors"]).to eq(
+          [
+            {
+              "status" => "406",
+              "title" => "RDF representation is not available for this DOI",
+            },
+          ],
+        )
+      end
+    end
+
+    context "application/rdf+xml link" do
+      it "returns the Doi as RDF/XML" do
+        get "/application/rdf+xml/#{doi_with_xml.doi}"
+
+        expect(last_response.status).to eq(200)
+        expect(last_response.headers["Content-Type"]).to include("application/rdf+xml")
+        expect(last_response.body).to include("rdf:RDF")
+      end
+    end
+
+    context "text/turtle" do
+      it "returns the Doi as Turtle" do
+        get "/#{doi_with_xml.doi}", nil, { "HTTP_ACCEPT" => "text/turtle" }
+
+        expect(last_response.status).to eq(200)
+        expect(last_response.headers["Content-Type"]).to include("text/turtle")
+        expect(last_response.body).to include("@prefix schema:")
+      end
+
+      it "returns 406 when RDF representation is not available" do
+        get "/#{doi.doi}", nil, { "HTTP_ACCEPT" => "text/turtle" }
+
+        expect(last_response.status).to eq(406)
+        expect(json["errors"]).to eq(
+          [
+            {
+              "status" => "406",
+              "title" => "RDF representation is not available for this DOI",
+            },
+          ],
+        )
+      end
+    end
+
+    context "application/x-turtle" do
+      it "returns the Doi as Turtle" do
+        get "/#{doi_with_xml.doi}", nil, { "HTTP_ACCEPT" => "application/x-turtle" }
+
+        expect(last_response.status).to eq(200)
+        expect(last_response.headers["Content-Type"]).to include("turtle")
+        expect(last_response.body).to include("@prefix schema:")
+      end
+    end
+
+    context "text/turtle link" do
+      it "returns the Doi as Turtle" do
+        get "/text/turtle/#{doi_with_xml.doi}"
+
+        expect(last_response.status).to eq(200)
+        expect(last_response.headers["Content-Type"]).to include("text/turtle")
+        expect(last_response.body).to include("@prefix schema:")
+      end
+    end
+
+    context "application/x-turtle link" do
+      it "returns the Doi as Turtle" do
+        get "/application/x-turtle/#{doi_with_xml.doi}"
+
+        expect(last_response.status).to eq(200)
+        expect(last_response.headers["Content-Type"]).to include("turtle")
+        expect(last_response.body).to include("@prefix schema:")
+      end
+    end
   end
 end