[i335] - port over serverless code from nnp (#198)

* [i335] - port over serverless code from nnp

* [i335] - implement serverless iiif, move code into  DisplayImagePresenterBehavior

TODO: Loading issue in dev; when we change code the app no longer hits our iiif_manifest_presenter_behavior.rb and reverts back to using the app instead of cloudfront. We also added the prepend in the after_intitialize because the app couldn't find the digest method otherwise.

* [i335] rubocop fix

* Add test and refactor

This commit will add a test for #display_image.  Also, a refactor was
introduced to account for both Hyrax 2 and 3.  The method signature
of the `Hyrax.config.iiif_image_url_builder` lambda changed to add an
additional argument in Hyrax 3.

ref: https://github.com/samvera/hyrax/blob/2.x-stable/lib/hyrax/configuration.rb#L397-L399
ref: https://github.com/samvera/hyrax/blob/3.x-stable/lib/hyrax/configuration.rb#L250-L252

* Refactor `DisplayImagePresenterBehavior`

This commit will add OVERRIDE comments where useful and add a blurb in
the README for this new feature.  The #display_content method was added
to support presentation 3 manifests.  `SERVERLESS` has been renamed to
`EXTERNAL`.  `DisplayImagePresenterBehavior` has beeen refactored to
incorporate existing code.  Specs have also been refactored.

* add EXTERNAL_IIIF_URL instructions to the README

---------

Co-authored-by: Kirk Wang <[email protected]>
Co-authored-by: Rob Kaufman <[email protected]>

README.md

@@ -37,6 +37,7 @@ IiifPrint supports:
 * splitting of PDFs to LZW compressed TIFFs for viewing
 * adding metadata fields to the manifest with faceted search links and external links
 * excluding specified work types to be found in the catalog search
+* external IIIF image urls that work with services such as serverless-iiif or cantaloup
 
 A complete list of features can be found [here](https://github.com/scientist-softserv/iiif_print/wiki/Features-List).
 
@@ -91,6 +92,10 @@ IiifPrint easily integrates with your Hyrax 2.x applications.
 ## Configuration to enable IiifPrint features
 **NOTE: WorkTypes and models are used synonymously here.**
 
+### IIIF URL configuration
+
+If you set EXTERNAL_IIIF_URL in your environment, then IiifPrint will use that URL as the root for your IIIF URLs. It will also switch from using the file set ID to using the SHA1 of the file as the identifier. This enables using serverless_iiif or Cantaloupe (refered to as the service) by pointing the service to the same S3 bucket that FCREPO writes the uploaded files to. By setting it up that way you do not need the service to connect to FCREPO or Hyrax at all, both natively support connecting to an S3 bucket to get their data.
+
 ### Model level configurations
 
 In `app/models/{work_type}.rb` add `include IiifPrint.model_configuration` to any work types which require IiifPrint processing features (such as PDF splitting or OCR derivatives). See [lib/iiif_print.rb](./lib/iiif_print.rb) for details on configuration options.

app/indexers/concerns/iiif_print/file_set_indexer.rb

@@ -23,7 +23,15 @@ def generate_solr_document
         text = text.tr("\n", ' ').squeeze(' ')
         solr_doc['all_text_timv'] = text
         solr_doc['all_text_tsimv'] = text
+        solr_doc['digest_ssim'] = digest_from_content
       end
     end
+
+    private
+
+    def digest_from_content
+      return unless object.original_file
+      object.original_file.digest.first.to_s
+    end
   end
 end

app/models/concerns/iiif_print/solr/document.rb

@@ -19,6 +19,7 @@ module IiifPrint::Solr::Document
   def self.decorate(base)
     base.prepend(self)
     base.send(:attribute, :is_child, Hyrax::SolrDocument::Metadata::Solr::String, 'is_child_bsi')
+    base.send(:attribute, :digest, Hyrax::SolrDocument::Metadata::Solr::String, 'digest_ssim')
 
     # @note These properties came from the newspaper_works gem.  They are configurable.
     base.class_attribute :iiif_print_solr_field_names, default: %w[alternative_title genre
@@ -31,6 +32,10 @@ def self.decorate(base)
     base
   end
 
+  def digest_sha1
+    digest[/urn:sha1:([\w]+)/, 1]
+  end
+
   def method_missing(method_name, *args, &block)
     super unless iiif_print_solr_field_names.include? method_name.to_s
     self[::ActiveFedora.index_field_mapper.solr_name(method_name.to_s)]

app/presenters/iiif_print/iiif_manifest_presenter_behavior.rb

@@ -3,6 +3,10 @@ module IiifPrint
   module IiifManifestPresenterBehavior
     extend ActiveSupport::Concern
 
+    # Extending the presenter to the base url which includes the protocol.
+    # We need the base url to render the facet links and normalize the interface.
+    attr_accessor :base_url
+
     def manifest_metadata
       @manifest_metadata ||= IiifPrint.manifest_metadata_from(work: model, presenter: self)
     end
@@ -11,7 +15,7 @@ def search_service
       Rails.application.routes.url_helpers.solr_document_iiif_search_url(id, host: hostname)
     end
 
-    # OVERRIDE Hyrax 3x, avoid nil returning to IIIF Manifest gem
+    # OVERRIDE: Hyrax 3x, avoid nil returning to IIIF Manifest gem
     # @see https://github.com/samvera/iiif_manifest/blob/c408f90eba11bef908796c7236ba6bcf8d687acc/lib/iiif_manifest/v3/manifest_builder/record_property_builder.rb#L28
     ##
     # @return [Array<Hash{String => String}>]
@@ -25,5 +29,101 @@ def sequence_rendering
           'label' => I18n.t("hyrax.manifest.download_text") + (rendering.label || '') }
       end.flatten
     end
+
+    # OVERRIDE: Hyrax v3.x
+    module DisplayImagePresenterBehavior
+      # Extending the presenter to the base url which includes the protocol.
+      # We need the base url to render the facet links and normalize the interface.
+      attr_accessor :base_url
+
+      # Extending this class because there is an #ability= but not #ability and this definition
+      # mirrors the Hyrax::IiifManifestPresenter#ability.
+      def ability
+        @ability ||= NullAbility.new
+      end
+
+      def display_image
+        return nil unless latest_file_id
+        return nil unless model.image?
+        return nil unless IiifPrint.config.default_iiif_manifest_version == 2
+
+        IIIFManifest::DisplayImage
+          .new(display_image_url(hostname),
+            format: image_format(alpha_channels),
+            width: width,
+            height: height,
+            iiif_endpoint: iiif_endpoint(latest_file_id, base_url: hostname))
+      end
+
+      # OVERRIDE: IIIF Hyrax AV v0.2 #display_content for prez 3 manifests
+      def display_content
+        return nil unless latest_file_id
+        return super unless model.image?
+
+        IIIFManifest::V3::DisplayContent
+          .new(display_image_url(hostname),
+            format: image_format(alpha_channels),
+            width: width,
+            height: height,
+            type: 'Image',
+            iiif_endpoint: iiif_endpoint(latest_file_id, base_url: hostname))
+      end
+
+      def display_image_url(base_url)
+        if ENV['EXTERNAL_IIIF_URL'].present?
+          # At the moment we are only concerned about Hyrax's default image url builder
+          iiif_image_url_builder(url_builder: Hyrax.config.iiif_image_url_builder)
+        else
+          super
+        end
+      end
+
+      def iiif_endpoint(file_id, base_url: request.base_url)
+        if ENV['EXTERNAL_IIIF_URL'].present?
+          IIIFManifest::IIIFEndpoint.new(
+            File.join(ENV['EXTERNAL_IIIF_URL'], file_id),
+            profile: Hyrax.config.iiif_image_compliance_level_uri
+          )
+        else
+          super
+        end
+      end
+
+      def hostname
+        @hostname || 'localhost'
+      end
+
+      ##
+      # @return [Boolean] false
+      def work?
+        false
+      end
+
+      private
+
+      def latest_file_id
+        if ENV['EXTERNAL_IIIF_URL'].present?
+          external_latest_file_id
+        else
+          super
+        end
+      end
+
+      def external_latest_file_id
+        @latest_file_id ||= digest_sha1
+      end
+
+      def iiif_image_url_builder(url_builder:)
+        args = [
+          latest_file_id,
+          ENV['EXTERNAL_IIIF_URL'],
+          Hyrax.config.iiif_image_size_default
+        ]
+        # In Hyrax 3, Hyrax.config.iiif_image_url_builder takes an additional argument
+        args << image_format(alpha_channels) if url_builder.arity == 4
+
+        url_builder.call(*args).gsub(%r{images/}, '')
+      end
+    end
   end
 end

lib/iiif_print/engine.rb

@@ -49,19 +49,6 @@ class Engine < ::Rails::Engine
       ::BlacklightIiifSearch::IiifSearchAnnotation.prepend(IiifPrint::BlacklightIiifSearch::AnnotationDecorator)
       Hyrax::Actors::FileSetActor.prepend(IiifPrint::Actors::FileSetActorDecorator)
 
-      # Extending the presenter to the base url which includes the protocol.
-      # We need the base url to render the facet links and normalize the interface.
-      Hyrax::IiifManifestPresenter.send(:attr_accessor, :base_url)
-      Hyrax::IiifManifestPresenter::DisplayImagePresenter.send(:attr_accessor, :base_url)
-      # Extending this class because there is an #ability= but not #ability and this definition
-      # mirrors the Hyrax::IiifManifestPresenter#ability.
-      module Hyrax::IiifManifestPresenter::DisplayImagePresenterDecorator
-        def ability
-          @ability ||= NullAbility.new
-        end
-      end
-      Hyrax::IiifManifestPresenter::DisplayImagePresenter.prepend(Hyrax::IiifManifestPresenter::DisplayImagePresenterDecorator)
-
       Hyrax.config do |config|
         config.callback.set(:after_create_fileset) do |file_set, user|
           IiifPrint.config.handle_after_create_fileset(file_set, user)
@@ -71,6 +58,8 @@ def ability
 
     config.after_initialize do
       IiifPrint::Solr::Document.decorate(SolrDocument)
+      Hyrax::IiifManifestPresenter::DisplayImagePresenter
+        .prepend(IiifPrint::IiifManifestPresenterBehavior::DisplayImagePresenterBehavior)
     end
     # rubocop:enable Metrics/BlockLength
   end

spec/presenters/iiif_print/iiif_manifest_presenter_behavior_spec.rb

@@ -16,4 +16,55 @@
       expect(presenter.search_service).to include("#{solr_document.id}/iiif_search")
     end
   end
+
+  context 'with IIIF external support' do
+    let(:presenter) { Hyrax::IiifManifestPresenter::DisplayImagePresenter.new(solr_document) }
+    let(:id) { 'abc123' }
+    let(:url) { 'external_iiif_url' }
+    let(:iiif_info_url_builder) { ->(file_id, base_url) { "#{base_url}/#{file_id}" } }
+
+    before { allow(solr_document).to receive(:image?).and_return(true) }
+
+    context 'when external iiif is enabled' do
+      before do
+        allow(ENV).to receive(:[])
+        allow(ENV).to receive(:[]).with('EXTERNAL_IIIF_URL').and_return(url)
+        allow(presenter).to receive(:latest_file_id).and_return(id)
+      end
+
+      describe '#display_image' do
+        it 'renders a external url' do
+          expect(presenter.display_image.iiif_endpoint.url).to eq "#{url}/#{id}"
+          expect(presenter.display_image.iiif_endpoint.profile).to eq "http://iiif.io/api/image/2/level2.json"
+        end
+      end
+
+      describe '#display_content' do
+        it 'renders a external url' do
+          expect(presenter.display_content.iiif_endpoint.url).to eq "#{url}/#{id}"
+          expect(presenter.display_content.iiif_endpoint.profile).to eq "http://iiif.io/api/image/2/level2.json"
+        end
+      end
+    end
+
+    context 'when external iiif is not enabled' do
+      before do
+        allow(presenter).to receive(:latest_file_id).and_return(id)
+        allow(Hyrax.config).to receive(:iiif_image_server?).and_return(true)
+        allow(Hyrax.config).to receive(:iiif_info_url_builder).and_return(iiif_info_url_builder)
+      end
+
+      describe '#display_image' do
+        it 'does not render a external url' do
+          expect(presenter.display_image.iiif_endpoint.url).to eq "localhost/#{id}"
+        end
+      end
+
+      describe '#display_content' do
+        it 'does not render a external url' do
+          expect(presenter.display_content.iiif_endpoint.url).to eq "localhost/#{id}"
+        end
+      end
+    end
+  end
 end