From 24899ac7502f470f2c963dcfbdd5e26a306ce0f1 Mon Sep 17 00:00:00 2001
From: Julie Allinson <julie.allinson@london.ac.uk>
Date: Tue, 18 Jul 2017 18:57:31 +0100
Subject: [PATCH] support for an optional 'manifest_extras' method to initially
 support adding rendering to sequences

---
 README.md                                     | 14 +++++-
 .../manifest_builder/sequence_builder.rb      |  9 ++++
 .../iiif_manifest/manifest_factory_spec.rb    | 50 +++++++++++++++++++
 3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index b77227e..864a8b6 100644
--- a/README.md
+++ b/README.md
@@ -5,11 +5,17 @@ IIIF http://iiif.io/ defines an API for presenting related images in a viewer. T
 
 ## Usage
 
-You application must have an object that implements `#file_set_presenters` and `#work_presenters`.  The former method should return as set of leaf nodes and the later any interstitial nodes. If none are found an empty array should be returned. Additionally it should implement `#manifest_url` that shows where the manifest can be found. Finally, it must have a `#description` method that returns a string.
+Your application ***must*** have an object that implements `#file_set_presenters` and `#work_presenters`.  The former method should return as set of leaf nodes and the later any interstitial nodes. If none are found an empty array should be returned. 
+
+Additionally, it ***must*** have a `#description` method that returns a string.
+
+Additionally it ***should*** implement `#manifest_url` that shows where the manifest can be found. 
+
+Finally, it ***may*** implement `#sequence_rendering` to contain an array of hashes for file downloads to be offered at sequences level. Each hash must contain "@id", "format" (mime type) and "label" (eg. `{ "@id" => "download url", "format" => "application/pdf", "label" => "user friendly label" }`). 
 
 For example:
 
-```ruby
+ ```ruby
   class Book
     def initialize(id, pages = [])
       @id = id
@@ -31,6 +37,10 @@ For example:
     def description
       'a brief description'
     end
+    
+    def sequence_rendering:
+      [{"@id" => "http://test.host/file_set/id/download", "format" => "application/pdf", "label" => "Download"}]
+    end
   end
 ```
 
diff --git a/lib/iiif_manifest/manifest_builder/sequence_builder.rb b/lib/iiif_manifest/manifest_builder/sequence_builder.rb
index e564b1a..155c6ce 100644
--- a/lib/iiif_manifest/manifest_builder/sequence_builder.rb
+++ b/lib/iiif_manifest/manifest_builder/sequence_builder.rb
@@ -28,10 +28,19 @@ def sequence
             begin
               sequence = IIIF::Presentation::Sequence.new
               sequence["@id"] ||= work.manifest_url + "/sequence/normal"
+              sequence["rendering"] ||= populate_sequence_rendering
               canvas_builder.apply(sequence)
               sequence
             end
         end
+
+        def populate_sequence_rendering
+          if work.respond_to?(:sequence_rendering)
+            work.sequence_rendering.each { | x | x.to_h }
+          else
+            []
+          end
+        end
     end
   end
 end
diff --git a/spec/lib/iiif_manifest/manifest_factory_spec.rb b/spec/lib/iiif_manifest/manifest_factory_spec.rb
index 767da86..c5575ba 100644
--- a/spec/lib/iiif_manifest/manifest_factory_spec.rb
+++ b/spec/lib/iiif_manifest/manifest_factory_spec.rb
@@ -22,6 +22,7 @@ def file_set_presenters
       def work_presenters
         []
       end
+
       def manifest_url
         "http://test.host/books/#{@id}/manifest"
       end
@@ -46,6 +47,7 @@ def display_image
   describe "#to_h" do
     let(:result) { subject.to_h }
     let(:json_result) { JSON.parse(subject.to_h.to_json) }
+
     it "has a label" do
       expect(result.label).to eq book_presenter.to_s
     end
@@ -73,6 +75,54 @@ def display_image
       end
     end
 
+    context "where there is a no sequence_rendering method" do
+      let(:file_presenter) { DisplayImagePresenter.new }
+
+      it "does not have a rendering on the sequence" do
+        allow(IIIFManifest::ManifestBuilder::CanvasBuilder).to receive(:new).and_call_original
+        allow(book_presenter).to receive(:file_set_presenters).and_return([file_presenter])
+        expect(result['sequences'][0]['rendering']).to eq []
+      end
+    end
+
+    context "where there is a sequence_rendering method" do
+      let(:file_presenter) { DisplayImagePresenter.new }
+      before do
+        class Book
+          def initialize(id)
+            @id = id
+          end
+
+          def description
+            'a brief description'
+          end
+
+          def file_set_presenters
+            []
+          end
+
+          def work_presenters
+            []
+          end
+
+          def manifest_url
+            "http://test.host/books/#{@id}/manifest"
+          end
+
+          def sequence_rendering
+            [{ "@id" => "http://test.host/file_set/id/download", "format" => "application/pdf", "label" => "Download" }]
+          end
+        end
+      end
+
+      it "has a rendering on the sequence" do
+        allow(IIIFManifest::ManifestBuilder::CanvasBuilder).to receive(:new).and_call_original
+        allow(book_presenter).to receive(:file_set_presenters).and_return([file_presenter])
+
+        expect(result['sequences'][0]['rendering']).to eq [{ "@id" => "http://test.host/file_set/id/download", "format" => "application/pdf", "label" => "Download" }]
+      end
+    end
+
     context "when there are child works" do
       let(:child_work_presenter) { presenter_class.new('test2') }
       before do