Make IIIF canvases and annotations resolvable over HTTP using a more …

…permanent url scheme

app/controllers/purl_controller.rb

@@ -45,7 +45,6 @@ def show
       end
     end
   end
-  # rubocop:enable Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity
 
   def manifest
     return unless stale?(last_modified: @purl.updated_at.utc, etag: @purl.cache_key + "/#{@purl.updated_at.utc}")
@@ -61,6 +60,35 @@ def manifest
     end
   end
 
+  def canvas
+    return unless stale?(last_modified: @purl.updated_at.utc, etag: @purl.cache_key + "/#{@purl.updated_at.utc}")
+
+    if @purl.iiif_manifest?
+      manifest = Rails.cache.fetch([@purl, @purl.updated_at.utc], expires_in: Settings.resource_cache.lifetime) do
+        @purl.iiif_manifest.canvas(controller: self, resource_id: params[:resource_id]).to_ordered_hash
+      end
+
+      render json: manifest
+    else
+      head :not_found
+    end
+  end
+
+  def annotation
+    return unless stale?(last_modified: @purl.updated_at.utc, etag: @purl.cache_key + "/#{@purl.updated_at.utc}")
+
+    if @purl.iiif_manifest?
+      manifest = Rails.cache.fetch([@purl, @purl.updated_at.utc], expires_in: Settings.resource_cache.lifetime) do
+        @purl.iiif_manifest.annotation(controller: self, annotation_id: params[:annotation_id]).to_ordered_hash
+      end
+
+      render json: manifest
+    else
+      head :not_found
+    end
+  end
+  # rubocop:enable Metrics/AbcSize, Metrics/MethodLength, Metrics/PerceivedComplexity
+
   private
 
   # validate that the id is of the proper format

app/models/iiif_presentation_manifest.rb

@@ -89,32 +89,54 @@ def body(controller = nil)
     manifest.thumbnail = thumbnail_resource
 
     # for each resource image, create a canvas
-    page_images.each_with_index do |resource, count|
+    page_images.each do |resource|
       next unless purl_resource.rights.world_rights_for_file(resource.filename).first ||
                   purl_resource.rights.stanford_only_rights_for_file(resource.filename).first
 
-      sequence.canvases << canvas_for_resource(purl_base_uri, resource, count)
+      sequence.canvases << canvas_for_resource(purl_base_uri, resource)
     end
 
     manifest.sequences << sequence
     manifest
   end
 
-  ##
-  # @param [Integer] count This is the i_th (image) resource
-  def canvas_for_resource(purl_base_uri, resource, count)
-    url = stacks_iiif_base_url(resource.druid, resource.filename)
+  def canvas(controller: nil, resource_id:)
+    controller ||= Rails.application.routes.url_helpers
+    purl_base_uri = controller.purl_url(druid)
+
+    resource = page_images.find { |image| image.id == resource_id }
+
+    canvas_for_resource(purl_base_uri, resource)
+  end
+
+  def annotation(controller: nil, annotation_id:)
+    controller ||= Rails.application.routes.url_helpers
+    purl_base_uri = controller.purl_url(druid)
+
+    resource = page_images.find { |image| image.id == annotation_id }
+
+    annotation_for_resource(purl_base_uri, resource)
+  end
 
+  def canvas_for_resource(purl_base_uri, resource)
     canv = IIIF::Presentation::Canvas.new
-    canv['@id'] = "#{purl_base_uri}/iiif/canvas-#{count}"
+    canv['@id'] = "#{purl_base_uri}/iiif/canvas/#{resource.id}"
     canv.label = resource.label
     canv.label = 'image' unless canv.label.present?
     canv.height = resource.height
     canv.width = resource.width
 
-    anno = IIIF::Presentation::Annotation.new
-    anno['@id'] = "#{purl_base_uri}/iiif/anno-#{count}"
+    anno = annotation_for_resource(purl_base_uri, resource)
     anno['on'] = canv['@id']
+    canv.images << anno
+    canv
+  end
+
+  def annotation_for_resource(purl_base_uri, resource)
+    url = stacks_iiif_base_url(resource.druid, resource.filename)
+
+    anno = IIIF::Presentation::Annotation.new
+    anno['@id'] = "#{purl_base_uri}/iiif/annotation/#{resource.id}"
 
     img_res = IIIF::Presentation::ImageResource.new
     img_res['@id'] = "#{url}/full/full/0/default.jpg"
@@ -139,8 +161,7 @@ def canvas_for_resource(purl_base_uri, resource, count)
     end
 
     anno.resource = img_res
-    canv.images << anno
-    canv
+    anno
   end
   # rubocop:enable Metrics/AbcSize, Metrics/MethodLength
 

config/routes.rb

@@ -11,5 +11,7 @@
 
   get ':id' => 'purl#show', as: :purl
   get ':id/embed', to: redirect("/iframe/?url=#{Settings.embed.url % { druid: '%{id}' }}")
-  get '/:id/iiif/manifest.json' => 'purl#manifest', as: :iiif_manifest
+  get '/:id/iiif/manifest' => 'purl#manifest', as: :iiif_manifest
+  get '/:id/iiif/canvas/:resource_id' => 'purl#canvas', as: :iiif_canvas
+  get '/:id/iiif/annotation/:annotation_id' => 'purl#annotation', as: :iiif_annotation
 end

spec/integration/purl_spec.rb

@@ -41,6 +41,30 @@
     end
   end
 
+  describe 'canvas' do
+    it 'renders the json for manifest' do
+      visit "/#{@manifest_object}/iiif/canvas/bc854fy5899_1.json"
+      json_body = JSON.parse(page.body)
+      expect(json_body['label']).to eq('John Wyclif and his followers, Tracts in Middle English')
+    end
+    it 'renders nil for a non-manifest' do
+      visit "/#{@file_object}/iiif/canvas/bc854fy5899_fdsa.json"
+      expect(page.status_code).to eq(404)
+    end
+  end
+
+  describe 'annotation' do
+    it 'renders the json for manifest' do
+      visit "/#{@manifest_object}/iiif/annotation/bc854fy5899_1.json"
+      json_body = JSON.parse(page.body)
+      expect(json_body['label']).to eq('John Wyclif and his followers, Tracts in Middle English')
+    end
+    it 'renders nil for a non-manifest' do
+      visit "/#{@file_object}/iiif/annotation/bc854fy5899_fdsa.json"
+      expect(page.status_code).to eq(404)
+    end
+  end
+
   context 'incomplete/unpublished object (not in stacks)' do
     it 'gives 404 with unavailable message' do
       visit "/#{@unpublished_object}"