Merge pull request #5315 from avalonmediasystem/blank_canvas

Use blank canvas to represent inaccesible playlist items

app/controllers/playlists_controller.rb

@@ -247,10 +247,14 @@ def manifest
     authorize! :read, @playlist
 
     canvas_presenters = @playlist.items.collect do |item|
-      next if item.clip.master_file.nil?
+      cannot_read_item = cannot? :read, @master_file
       @master_file = item.clip.master_file
-      stream_info = secure_streams(@master_file.stream_details, @master_file.media_object_id)
-      IiifPlaylistCanvasPresenter.new(playlist_item: item, stream_info: stream_info)
+      stream_info = if @master_file.nil?
+                      nil
+                    else
+                      secure_streams(@master_file.stream_details, @master_file.media_object_id)
+                    end
+      IiifPlaylistCanvasPresenter.new(playlist_item: item, stream_info: stream_info, cannot_read_item: cannot_read_item)
     end
     presenter = IiifPlaylistManifestPresenter.new(playlist: @playlist, items: canvas_presenters)
 

app/models/iiif_playlist_canvas_presenter.rb

@@ -13,19 +13,26 @@
 # ---  END LICENSE_HEADER BLOCK  ---
 
 class IiifPlaylistCanvasPresenter
-  attr_reader :playlist_item, :stream_info
+  attr_reader :playlist_item, :stream_info, :cannot_read_item
   attr_accessor :media_fragment
 
-  def initialize(playlist_item:, stream_info:, media_fragment: nil)
+  def initialize(playlist_item:, stream_info:, cannot_read_item: false, media_fragment: nil)
     @playlist_item = playlist_item
     @stream_info = stream_info
+    @cannot_read_item = cannot_read_item
     @media_fragment = media_fragment
   end
 
   delegate :id, to: :playlist_item
 
   def to_s
-    playlist_item.title
+    if cannot_read_item
+      "Restricted item"
+    elsif master_file.nil?
+      "Deleted item"
+    else
+      playlist_item.title
+    end
   end
 
   def master_file
@@ -45,15 +52,31 @@ def range
 
   # @return [IIIFManifest::V3::DisplayContent] the display content required by the manifest builder.
   def display_content
+    return if cannot_read_item || master_file.nil?
     master_file.is_video? ? video_content : audio_content
   end
 
   def annotation_content
+    return if cannot_read_item || master_file.nil?
     playlist_item.marker.collect { |m| marker_content(m) }
   end
 
-  private
+  def placeholder_content
+    if cannot_read_item
+      IIIFManifest::V3::DisplayContent.new(nil,
+                                           label: 'You do not have permission to playback this item.',
+                                           type: 'Text',
+                                           format: 'text/plain')
+    elsif master_file.nil?
+      IIIFManifest::V3::DisplayContent.new(nil,
+                                           label: 'The source for this playlist item has been deleted.',
+                                           type: 'Text',
+                                           format: 'text/plain')
+    end
+  end
 
+  private
+
     def video_content
       # @see https://github.com/samvera-labs/iiif_manifest
       stream_urls.collect { |quality, _url| video_display_content(quality) }

spec/models/iiif_playlist_canvas_presenter_spec.rb

@@ -23,7 +23,30 @@
   let(:stream_info) { master_file.stream_details }
   let(:presenter) { described_class.new(playlist_item: playlist_item, stream_info: stream_info) }
 
-  context 'auth_service' do
+  describe '#to_s' do
+    it 'returns the playlist_item label' do
+      expect(presenter.to_s).to eq playlist_item.title
+    end
+
+    context 'when a user does not have access to a restricted item' do
+      let(:presenter) { described_class.new(playlist_item: playlist_item, stream_info: stream_info, cannot_read_item: true) }
+
+      it 'return "Restricted item"' do
+        expect(presenter.to_s).to eq "Restricted item"
+      end
+    end
+
+    context 'when an item has been deleted' do
+      let(:master_file) { nil }
+      let(:stream_info) { nil }
+
+      it 'returns "Deleted item"' do
+        expect(presenter.to_s).to eq "Deleted item"
+      end
+    end
+  end
+
+  describe '#auth_service' do
     subject { presenter.display_content.first.auth_service }
 
     it 'provides a cookie auth service' do
@@ -73,11 +96,28 @@
         expect(subject.url).to include("#t=#{playlist_item.start_time / 1000},#{playlist_item.end_time / 1000}")
       end
     end
+
+    context 'when a user does not have access to a restricted item' do
+      let(:presenter) { described_class.new(playlist_item: playlist_item, stream_info: stream_info, cannot_read_item: true) }
+
+      it 'does not serialize the content' do
+        expect(presenter.display_content).to be_nil
+      end
+    end
+
+    context 'when an item has been deleted' do
+      let(:master_file) { nil }
+      let(:stream_info) { nil }
+
+      it 'does not serialize the content' do
+        expect(presenter.display_content).to be_nil
+      end
+    end
   end
 
   describe '#annotation_content' do
     let(:marker) { FactoryBot.create(:avalon_marker) }
-    let(:playlist_item) { FactoryBot.create(:playlist_item, marker: [marker]) }
+    let(:playlist_item) { FactoryBot.build(:playlist_item, clip: playlist_clip, marker: [marker]) }
     subject { presenter.annotation_content }
 
     it "serializes playlist markers as iiif annotations" do
@@ -95,6 +135,23 @@
     it "includes 'highlighting' motivation" do
       expect(subject.first.motivation).to eq 'highlighting'
     end
+
+    context 'when a user does not have access to a restricted item' do
+      let(:presenter) { described_class.new(playlist_item: playlist_item, stream_info: stream_info, cannot_read_item: true) }
+
+      it 'does not serialize the content' do
+        expect(presenter.annotation_content).to be_nil
+      end
+    end
+
+    context 'when an item has been deleted' do
+      let(:master_file) { nil }
+      let(:stream_info) { nil }
+
+      it 'does not serialize the content' do
+        expect(presenter.annotation_content).to be_nil
+      end
+    end
   end
 
   describe '#range' do
@@ -115,4 +172,53 @@
       expect(subject.any? { |po| po["@id"] =~ /media_objects\/#{media_object.id}\/manifest/ }).to eq true
     end
   end
+
+  describe '#placeholder_contetnt' do
+    subject { presenter.placeholder_content }
+
+    it 'does not generate a placeholder for non-restricted items' do
+      expect(subject).to be_nil
+    end
+
+    context 'when a user does not have access to a restricted item' do
+      let(:presenter) { described_class.new(playlist_item: playlist_item, stream_info: stream_info, cannot_read_item: true) }
+
+      it 'generates placeholder canvas' do
+        expect(subject).to be_present
+      end
+
+      it 'has format' do
+        expect(subject.format).to eq "text/plain"
+      end
+
+      it 'has type' do
+        expect(subject.type).to eq "Text"
+      end
+
+      it 'has label' do
+        expect(subject.label).to eq "You do not have permission to playback this item."
+      end
+    end
+
+    context 'when an item has been deleted' do
+      let(:master_file) { nil }
+      let(:stream_info) { nil }
+
+      it 'generated placeholder canvas' do
+        expect(subject).to be_present
+      end
+
+      it 'has format' do
+        expect(subject.format).to eq "text/plain"
+      end
+
+      it 'has type' do
+        expect(subject.type).to eq "Text"
+      end
+
+      it 'has label' do
+        expect(subject.label).to eq "The source for this playlist item has been deleted."
+      end
+    end
+  end
 end