From 4efaf8dd10bd88166c2e9ab485521ccd81a1bf28 Mon Sep 17 00:00:00 2001
From: Julie Allinson <julie.allinson@london.ac.uk>
Date: Mon, 15 Apr 2019 15:26:52 +0000
Subject: [PATCH] Fix for #1505

---
 app/models/concerns/hyrax/basic_metadata.rb   |  2 +-
 app/services/hyrax/works/migration_service.rb | 33 +++++++++++++++++++
 lib/tasks/migrate.rake                        |  5 +++
 .../hyrax/works/migration_service_spec.rb     | 21 ++++++++++++
 4 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 app/services/hyrax/works/migration_service.rb
 create mode 100644 spec/services/hyrax/works/migration_service_spec.rb

diff --git a/app/models/concerns/hyrax/basic_metadata.rb b/app/models/concerns/hyrax/basic_metadata.rb
index 179ead0798..76588f39eb 100644
--- a/app/models/concerns/hyrax/basic_metadata.rb
+++ b/app/models/concerns/hyrax/basic_metadata.rb
@@ -16,7 +16,7 @@ module BasicMetadata
       property :contributor, predicate: ::RDF::Vocab::DC11.contributor
       property :description, predicate: ::RDF::Vocab::DC11.description
       property :abstract, predicate: ::RDF::Vocab::DC.abstract
-      property :keyword, predicate: ::RDF::Vocab::DC11.relation
+      property :keyword, predicate: ::RDF::Vocab::SCHEMA.keywords
       # Used for a license
       property :license, predicate: ::RDF::Vocab::DC.rights
 
diff --git a/app/services/hyrax/works/migration_service.rb b/app/services/hyrax/works/migration_service.rb
new file mode 100644
index 0000000000..ee8a6bac45
--- /dev/null
+++ b/app/services/hyrax/works/migration_service.rb
@@ -0,0 +1,33 @@
+module Hyrax
+  module Works
+    class MigrationService
+      # @api public
+      #
+      # Migrate data stored in FCrepo from one predicate to another
+      #   The main use case is where the predicate used for a specific property is changed.
+      #   Data already stored in Fedora under the original predicate needs to be transfered
+      #   and the original data cleaned up.
+      def self.migrate_predicate(predicate_from, predicate_to, works_to_update = ActiveFedora::Base.all)
+        migrated = 0
+        Rails.logger.info "*** Migrating #{predicate_from} to #{predicate_to} in #{works_to_update.count} works"
+        works_to_update.each do |work|
+          next unless work.ldp_source.content.include?(predicate_from.to_s)
+          migrate_data(predicate_from, predicate_to, work)
+          migrated += 1
+        end
+        Rails.logger.info "--- Migration Complete (#{migrated} migrated)"
+      end
+
+      # @api private
+      #
+      # Migrate data
+      def self.migrate_data(predicate_from, predicate_to, work)
+        orm = Ldp::Orm.new(work.ldp_source)
+        orm.value(predicate_from).each { |val| orm.graph.insert([orm.resource.subject_uri, predicate_to, val.to_s]) }
+        orm.graph.delete([orm.resource.subject_uri, predicate_from, nil])
+        orm.save
+        Rails.logger.info " Data migrated from #{predicate_from} to #{predicate_to} - id: #{work.id}"
+      end
+    end
+  end
+end
diff --git a/lib/tasks/migrate.rake b/lib/tasks/migrate.rake
index 50a0997818..00af5ed12e 100644
--- a/lib/tasks/migrate.rake
+++ b/lib/tasks/migrate.rake
@@ -34,5 +34,10 @@ namespace :hyrax do
       # added in Hyrax 2.1.0
       Hyrax::Collections::MigrationService.migrate_all_collections
     end
+
+    # Migrate any orphan fedora data from the first to the second predicate
+    task migrate_keyword_predicate: :environment do
+      Hyrax::Works::MigrationService.migrate_predicate(::RDF::Vocab::DC11.relation, ::RDF::Vocab::SCHEMA.keywords)
+    end
   end
 end
diff --git a/spec/services/hyrax/works/migration_service_spec.rb b/spec/services/hyrax/works/migration_service_spec.rb
new file mode 100644
index 0000000000..7f19831a94
--- /dev/null
+++ b/spec/services/hyrax/works/migration_service_spec.rb
@@ -0,0 +1,21 @@
+# rubocop:disable RSpec/InstanceVariable
+RSpec.describe Hyrax::Works::MigrationService, clean_repo: true do
+  let(:predicate_from) { ::RDF::Vocab::DC11.description }
+  let(:predicate_to) { ::RDF::Vocab::SCHEMA.description }
+
+  describe "#migrate_predicate" do
+    it "uses DC description by default" do
+      @work = GenericWork.create(title: ["War and Peace"], description: ["war", "peace"])
+      expect(@work.ldp_source.content).to include("http://purl.org/dc/elements/1.1/description")
+    end
+
+    it "updates to use SCHEMA description" do
+      @work = GenericWork.create(title: ["War and Peace"], description: ["war", "peace"])
+      described_class.migrate_predicate(predicate_from, predicate_to)
+      @work.reload
+      expect(@work.ldp_source.content).to include("http://schema.org/description")
+      expect(@work.ldp_source.content).not_to include("http://purl.org/dc/elements/1.1/description")
+    end
+  end
+end
+# rubocop:enable RSpec/InstanceVariable