Add HasOne Association

According to some PDC server's primary_key is multiple,
add a mapping in identity. Not sure if this a good implementation
or not.

JIRA: PDC-1685

lib/pdc/resource/associations.rb

@@ -1,6 +1,7 @@
 require 'pdc/resource/associations/has_many'
 require 'pdc/resource/associations/association'
 require 'pdc/resource/associations/builder'
+require 'pdc/resource/associations/has_one'
 
 module PDC::Resource
   module Associations
@@ -25,6 +26,14 @@ def has_many(name, options = {})
         end
       end
 
+      def has_one(name, options = {})
+        create_association(name, HasOne, options)
+
+        define_method "build_#{name}" do |attributes = nil|
+          association(name).build(attributes)
+        end
+      end
+
       private
 
       def create_association(name, type, options)

lib/pdc/resource/associations/association.rb

@@ -11,6 +11,10 @@ def initialize(klass, parent, name, options = {})
         @name = name
       end
 
+      def load
+        find_one! # Override for plural associations that return an association object
+      end
+
       private
 
       def foreign_key

lib/pdc/resource/associations/has_one.rb

@@ -0,0 +1,29 @@
+module PDC::Resource
+  module Associations
+    class HasOne < Association
+      def initialize(*args)
+        super
+        @options.reverse_merge!(uri: "#{parent.class.model_name.plural}/:#{foreign_key}/#{@name}")
+        collect_params
+      end
+
+      def collect_params
+        p_mapping = parent.class.mapping
+        s_foreign_key = foreign_key.to_s
+        if s_foreign_key.include? '/'
+          s_foreign_key.split('/').each do |fk|
+            p_mapping_value = p_mapping[fk.to_sym]
+            @params[fk] =
+              if p_mapping && p_mapping_value
+                parent.attributes[p_mapping_value.to_sym]
+              else
+                parent.attributes[fk]
+              end
+          end
+        else
+          @params[foreign_key] = parent.id
+        end
+      end
+    end
+  end
+end

lib/pdc/resource/identity.rb

@@ -24,6 +24,14 @@ def resource_path
         @resource_path ||= model_name.collection.sub(%r{^pdc\/}, '').tr('_', '-')
       end
 
+      def mapping
+        @mapping || {}
+      end
+
+      def mapping=(mapping = {})
+        @mapping = mapping
+      end
+
       private
 
       def default_uri

spec/pdc/resource/associations_spec.rb

@@ -28,17 +28,23 @@
         ProductVersion.new.non_existings
       end
     end
+  end
 
+  describe 'has many' do
     it 'has many association' do
       releases = ProductVersion.new(product_version_id: 'dp-1').releases.to_a
       assert_equal 'dp-1.0', releases.first.release_id
     end
+  end
 
+  describe 'find has many' do
     it 'find on has many association' do
       release = ProductVersion.new(product_version_id: 'dp-1').releases.find('dp-1.0')
       assert_equal 'dp-1.0', release.release_id
     end
+  end
 
+  describe 'scope' do
     it 'scopes on associations' do
       releases = ProductVersion.new(product_version_id: 'dp-1').releases.where(release_id: 'dp-1.0').to_a
       assert_equal 'dp-1.0', releases.first.release_id
@@ -98,4 +104,11 @@
       assert_requested endpoint2, times: 1
     end
   end
+
+  describe 'has_one' do
+    it 'has_one assocation' do
+      variant_cpe = ReleaseVariant.new(release: 'dp-1.0', uid: 'Client').variant_cpe
+      assert_equal 'cpe:/asdff', variant_cpe.cpe
+    end
+  end
 end

spec/support/fixtures.rb

@@ -137,4 +137,13 @@ class ProductVersion < Association
   class Release < Association
     self.primary_key = :release_id
   end
+
+  class ReleaseVariant < Association
+    has_one :variant_cpe, uri: 'rest_api/v1/variant-cpes/?release=:release&variant_uid=:uid', foreign_key: 'release/variant_uid'
+    self.mapping = { variant_uid: 'uid' }
+  end
+
+  class VariantCpe < Association
+    self.primary_key = :id
+  end
 end