Add find_by_alternate_identifier, for #207

lib/valkyrie/persistence/fedora/permissive_schema.rb

@@ -22,11 +22,19 @@ def self.id
       uri_for(:id)
     end
 
+    def self.alternate_ids
+      uri_for(:alternate_ids)
+    end
+
     # @return [RDF::URI]
     def self.member_ids
       uri_for(:member_ids)
     end
 
+    def self.references
+      uri_for(:references)
+    end
+
     # @return [RDF::URI]
     def self.valkyrie_bool
       uri_for(:valkyrie_bool)

lib/valkyrie/persistence/fedora/persister.rb

@@ -3,6 +3,7 @@ module Valkyrie::Persistence::Fedora
   # Persister for Fedora MetadataAdapter.
   class Persister
     require 'valkyrie/persistence/fedora/persister/resource_factory'
+    require 'valkyrie/persistence/fedora/persister/alternate_identifier'
     attr_reader :adapter
     delegate :connection, :base_path, :resource_factory, to: :adapter
     def initialize(adapter:)
@@ -16,14 +17,17 @@ def save(resource:)
       resource.updated_at ||= Time.current
       ensure_multiple_values!(resource)
       orm = resource_factory.from_resource(resource: resource)
+      alternate_resources = find_or_create_alternate_ids(resource)
+
       if !orm.new? || resource.id
-        orm.update do |req|
-          req.headers["Prefer"] = "handling=lenient; received=\"minimal\""
-        end
+        cleanup_alternate_resources(resource) if alternate_resources
+        orm.update { |req| req.headers["Prefer"] = "handling=lenient; received=\"minimal\"" }
       else
         orm.create
       end
-      resource_factory.to_resource(object: orm)
+      persisted_resource = resource_factory.to_resource(object: orm)
+
+      alternate_resources ? save_reference_to_resource(persisted_resource, alternate_resources) : persisted_resource
     end
 
     # (see Valkyrie::Persistence::Memory::Persister#save_all)
@@ -35,8 +39,15 @@ def save_all(resources:)
 
     # (see Valkyrie::Persistence::Memory::Persister#delete)
     def delete(resource:)
+      if resource.try(:alternate_ids)
+        resource.alternate_ids.each do |alternate_identifier|
+          adapter.persister.delete(resource: adapter.query_service.find_by(id: alternate_identifier))
+        end
+      end
+
       orm = resource_factory.from_resource(resource: resource)
       orm.delete
+
       resource
     end
 
@@ -60,10 +71,41 @@ def initialize_repository
     private
 
       def ensure_multiple_values!(resource)
-        bad_keys = resource.attributes.except(:internal_resource, :created_at, :updated_at, :new_record, :id).select do |_k, v|
+        bad_keys = resource.attributes.except(:internal_resource, :created_at, :updated_at, :new_record, :id, :references).select do |_k, v|
           !v.nil? && !v.is_a?(Array)
         end
         raise ::Valkyrie::Persistence::UnsupportedDatatype, "#{resource}: #{bad_keys.keys} have non-array values, which can not be persisted by Valkyrie. Cast to arrays." unless bad_keys.keys.empty?
       end
+
+      def find_or_create_alternate_ids(resource)
+        return nil unless resource.try(:alternate_ids)
+
+        resource.alternate_ids.map do |alternate_identifier|
+          begin
+            adapter.query_service.find_by(id: alternate_identifier)
+          rescue ::Valkyrie::Persistence::ObjectNotFoundError
+            alternate_resource = ::Valkyrie::Persistence::Fedora::AlternateIdentifier.new(id: alternate_identifier)
+            adapter.persister.save(resource: alternate_resource)
+          end
+        end
+      end
+
+      def cleanup_alternate_resources(updated_resource)
+        persisted_resource = adapter.query_service.find_by(id: updated_resource.id)
+        removed_identifiers = persisted_resource.alternate_ids - updated_resource.alternate_ids
+
+        removed_identifiers.each do |removed_id|
+          adapter.persister.delete(resource: adapter.query_service.find_by(id: removed_id))
+        end
+      end
+
+      def save_reference_to_resource(resource, alternate_resources)
+        alternate_resources.each do |alternate_resource|
+          alternate_resource.references = resource.id
+          adapter.persister.save(resource: alternate_resource)
+        end
+
+        resource
+      end
   end
 end

lib/valkyrie/persistence/fedora/persister/alternate_identifier.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+require 'valkyrie/resource'
+require 'valkyrie/types'
+
+module Valkyrie::Persistence::Fedora
+  class AlternateIdentifier < ::Valkyrie::Resource
+    attribute :id, ::Valkyrie::Types::ID.optional
+    attribute :references, ::Valkyrie::Types::ID.optional
+  end
+end

lib/valkyrie/persistence/fedora/query_service.rb

@@ -10,15 +10,19 @@ def initialize(adapter:)
 
     # (see Valkyrie::Persistence::Memory::QueryService#find_by)
     def find_by(id:)
-      id = Valkyrie::ID.new(id.to_s) if id.is_a?(String)
       validate_id(id)
       uri = adapter.id_to_uri(id)
-      begin
-        resource = Ldp::Resource.for(connection, uri, connection.get(uri))
-        resource_factory.to_resource(object: resource)
-      rescue ::Ldp::Gone, ::Ldp::NotFound
-        raise ::Valkyrie::Persistence::ObjectNotFoundError
-      end
+
+      resource_from_uri(uri)
+    end
+
+    # (see Valkyrie::Persistence::Memory::QueryService#find_by_alternate_identifier)
+    def find_by_alternate_identifier(alternate_identifier:)
+      validate_id(alternate_identifier)
+      uri = adapter.id_to_uri(alternate_identifier)
+      alternate_id = resource_from_uri(uri).references
+
+      find_by(id: alternate_id)
     end
 
     # (see Valkyrie::Persistence::Memory::QueryService#find_many_by_ids)
@@ -113,9 +117,17 @@ def custom_queries
     private
 
       def validate_id(id)
+        id = Valkyrie::ID.new(id.to_s) if id.is_a?(String)
         raise ArgumentError, 'id must be a Valkyrie::ID' unless id.is_a? Valkyrie::ID
       end
 
+      def resource_from_uri(uri)
+        resource = Ldp::Resource.for(connection, uri, connection.get(uri))
+        resource_factory.to_resource(object: resource)
+      rescue ::Ldp::Gone, ::Ldp::NotFound
+        raise ::Valkyrie::Persistence::ObjectNotFoundError
+      end
+
       def ensure_persisted(resource)
         raise ArgumentError, 'resource is not saved' unless resource.persisted?
       end

lib/valkyrie/persistence/memory/query_service.rb

@@ -24,6 +24,17 @@ def find_by(id:)
       cache[id] || raise(::Valkyrie::Persistence::ObjectNotFoundError)
     end
 
+    # @param alternate_identifier [Valkyrie::ID] The alternate identifier to query for.
+    # @raise [Valkyrie::Persistence::ObjectNotFoundError] Raised when the alternate identifier
+    #   isn't in the persistence backend.
+    # @raise [ArgumentError] Raised when alternate identifier is not a String or a Valkyrie::ID
+    # @return [Valkyrie::Resource] The object being searched for.
+    def find_by_alternate_identifier(alternate_identifier:)
+      alternate_identifier = Valkyrie::ID.new(alternate_identifier.to_s) if alternate_identifier.is_a?(String)
+      validate_id(alternate_identifier)
+      cache.select { |_key, resource| resource['alternate_ids'].include?(alternate_identifier) }.values.first || raise(::Valkyrie::Persistence::ObjectNotFoundError)
+    end
+
     # @param ids [Array<Valkyrie::ID, String>] The IDs to query for.
     # @raise [ArgumentError] Raised when any ID is not a String or a Valkyrie::ID
     # @return [Array<Valkyrie::Resource>] All requested objects that were found

lib/valkyrie/persistence/postgres/query_service.rb

@@ -37,6 +37,14 @@ def find_by(id:)
       raise Valkyrie::Persistence::ObjectNotFoundError
     end
 
+    # (see Valkyrie::Persistence::Memory::QueryService#find_by_alternate_identifier)
+    def find_by_alternate_identifier(alternate_identifier:)
+      alternate_identifier = Valkyrie::ID.new(alternate_identifier.to_s) if alternate_identifier.is_a?(String)
+      validate_id(alternate_identifier)
+      internal_array = "{\"alternate_ids\": [{\"id\": \"#{alternate_identifier}\"}]}"
+      run_query(find_inverse_references_query, internal_array).first || raise(Valkyrie::Persistence::ObjectNotFoundError)
+    end
+
     # (see Valkyrie::Persistence::Memory::QueryService#find_many_by_ids)
     def find_many_by_ids(ids:)
       ids.map! do |id|

lib/valkyrie/persistence/solr/queries.rb

@@ -6,6 +6,7 @@ module Queries
     require 'valkyrie/persistence/solr/queries/default_paginator'
     require 'valkyrie/persistence/solr/queries/find_all_query'
     require 'valkyrie/persistence/solr/queries/find_by_id_query'
+    require 'valkyrie/persistence/solr/queries/find_by_alternate_identifier_query'
     require 'valkyrie/persistence/solr/queries/find_many_by_ids_query'
     require 'valkyrie/persistence/solr/queries/find_inverse_references_query'
     require 'valkyrie/persistence/solr/queries/find_members_query'

lib/valkyrie/persistence/solr/queries/find_by_alternate_identifier_query.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+module Valkyrie::Persistence::Solr::Queries
+  # Responsible for returning a single resource identified by an ID.
+  class FindByAlternateIdentifierQuery
+    attr_reader :connection, :resource_factory
+    attr_writer :alternate_identifier
+    def initialize(alternate_identifier, connection:, resource_factory:)
+      @alternate_identifier = alternate_identifier
+      @connection = connection
+      @resource_factory = resource_factory
+    end
+
+    def run
+      raise ::Valkyrie::Persistence::ObjectNotFoundError unless resource
+      resource_factory.to_resource(object: resource)
+    end
+
+    def alternate_identifier
+      @alternate_identifier.to_s
+    end
+
+    def resource
+      connection.get("select", params: { q: "alternate_ids_ssim:\"id-#{alternate_identifier}\"", fl: "*", rows: 1 })["response"]["docs"].first
+    end
+  end
+end

lib/valkyrie/persistence/solr/query_service.rb

@@ -18,6 +18,13 @@ def find_by(id:)
       Valkyrie::Persistence::Solr::Queries::FindByIdQuery.new(id, connection: connection, resource_factory: resource_factory).run
     end
 
+    # (see Valkyrie::Persistence::Memory::QueryService#find_by_alternate_identifier)
+    def find_by_alternate_identifier(alternate_identifier:)
+      alternate_identifier = Valkyrie::ID.new(alternate_identifier.to_s) if alternate_identifier.is_a?(String)
+      validate_id(alternate_identifier)
+      Valkyrie::Persistence::Solr::Queries::FindByAlternateIdentifierQuery.new(alternate_identifier, connection: connection, resource_factory: resource_factory).run
+    end
+
     # (see Valkyrie::Persistence::Memory::QueryService#find_many_by_ids)
     def find_many_by_ids(ids:)
       ids.map! do |id|

lib/valkyrie/persistence/solr/repository.rb

@@ -39,7 +39,7 @@ def generate_id(resource)
     end
 
     def ensure_multiple_values!(resource)
-      bad_keys = resource.attributes.except(:internal_resource, :created_at, :updated_at, :new_record, :id).select do |_k, v|
+      bad_keys = resource.attributes.except(:internal_resource, :alternate_ids, :created_at, :updated_at, :new_record, :id).select do |_k, v|
         !v.nil? && !v.is_a?(Array)
       end
       raise ::Valkyrie::Persistence::UnsupportedDatatype, "#{resource}: #{bad_keys.keys} have non-array values, which can not be persisted by Valkyrie. Cast to arrays." unless bad_keys.keys.empty?

lib/valkyrie/specs/shared_specs/queries.rb

@@ -5,6 +5,7 @@
       defined? adapter
     class CustomResource < Valkyrie::Resource
       attribute :id, Valkyrie::Types::ID.optional
+      attribute :alternate_ids, Valkyrie::Types::Array
       attribute :title
       attribute :member_ids, Valkyrie::Types::Array
       attribute :a_member_of
@@ -25,6 +26,7 @@ class SecondResource < Valkyrie::Resource
   it { is_expected.to respond_to(:find_all).with(0).arguments }
   it { is_expected.to respond_to(:find_all_of_model).with_keywords(:model) }
   it { is_expected.to respond_to(:find_by).with_keywords(:id) }
+  it { is_expected.to respond_to(:find_by_alternate_identifier).with_keywords(:alternate_identifier) }
   it { is_expected.to respond_to(:find_many_by_ids).with_keywords(:ids) }
   it { is_expected.to respond_to(:find_members).with_keywords(:resource, :model) }
   it { is_expected.to respond_to(:find_references_by).with_keywords(:resource, :property) }
@@ -74,6 +76,44 @@ class SecondResource < Valkyrie::Resource
     end
   end
 
+  describe ".find_by_alternate_identifier" do
+    it "returns a resource by alternate identifier or string representation of an alternate identifier" do
+      resource = resource_class.new
+      resource.alternate_ids = [Valkyrie::ID.new('p9s0xfj')]
+      resource = persister.save(resource: resource)
+
+      found = query_service.find_by_alternate_identifier(alternate_identifier: resource.alternate_ids.first)
+      expect(found.id).to eq resource.id
+      expect(found).to be_persisted
+
+      found = query_service.find_by_alternate_identifier(alternate_identifier: resource.alternate_ids.first.to_s)
+      expect(found.id).to eq resource.id
+      expect(found).to be_persisted
+    end
+
+    it "returns a Valkyrie::Persistence::ObjectNotFoundError for a non-found alternate identifier" do
+      expect { query_service.find_by_alternate_identifier(alternate_identifier: Valkyrie::ID.new("123123123")) }.to raise_error ::Valkyrie::Persistence::ObjectNotFoundError
+    end
+
+    it 'raises an error if the alternate identifier is not a Valkyrie::ID or a string' do
+      expect { query_service.find_by_alternate_identifier(alternate_identifier: 123) }.to raise_error ArgumentError
+    end
+
+    it 'can have multiple alternate identifiers' do
+      resource = resource_class.new
+      resource.alternate_ids = [Valkyrie::ID.new('p9s0xfj'), Valkyrie::ID.new('jks0xfj')]
+      resource = persister.save(resource: resource)
+
+      found = query_service.find_by_alternate_identifier(alternate_identifier: resource.alternate_ids.first)
+      expect(found.id).to eq resource.id
+      expect(found).to be_persisted
+
+      found = query_service.find_by_alternate_identifier(alternate_identifier: resource.alternate_ids.last)
+      expect(found.id).to eq resource.id
+      expect(found).to be_persisted
+    end
+  end
+
   describe ".find_many_by_ids" do
     let!(:resource) { persister.save(resource: resource_class.new) }
     let!(:resource2) { persister.save(resource: resource_class.new) }