Adjusts Deserializer relationship parsing to allow links/meta keys

lib/active_model_serializers/adapter/json_api/deserialization.rb

@@ -7,6 +7,9 @@ class JsonApi
       module Deserialization
         InvalidDocument = Class.new(ArgumentError)
 
+        # http://jsonapi.org/format/#document-resource-object-relationships
+        VALID_RELATIONSHIP_KEYS = %w(links data meta).freeze
+
         module_function
 
         # Transform a JSON API document, containing a single data object,
@@ -132,8 +135,8 @@ def validate_payload(payload)
           end
 
           relationships.each do |(key, value)|
-            unless value.is_a?(Hash) && value.key?('data')
-              yield payload, { data: { relationships: { key => 'Expected hash with :data key' } } }
+            unless value.is_a?(Hash) && value.keys.any? { |k| VALID_RELATIONSHIP_KEYS.include?(k) }
+              yield payload, { data: { relationships: { key => "Expected hash with at least a #{VALID_RELATIONSHIP_KEYS.to_sentence(last_word_connector: 'or')} key" } } }
             end
           end
         end
@@ -163,6 +166,8 @@ def parse_attributes(attributes, options)
         # Given an association name, and a relationship data attribute, build a hash
         # mapping the corresponding ActiveRecord attribute to the corresponding value.
         #
+        # Ignores relationships specifying 'link' or 'meta' keys.
+        #
         # @example
         #   parse_relationship(:comments, [{ 'id' => '1', 'type' => 'comments' },
         #                                  { 'id' => '2', 'type' => 'comments' }],
@@ -173,12 +178,15 @@ def parse_attributes(attributes, options)
         #   parse_relationship(:author, nil, {})
         #    # => { :author_id => nil }
         # @param [Symbol] assoc_name
-        # @param [Hash] assoc_data
+        # @param [Hash] association
         # @param [Hash] options
         # @return [Hash{Symbol, Object}]
         #
         # @api private
-        def parse_relationship(assoc_name, assoc_data, options)
+        def parse_relationship(assoc_name, association, options)
+          return {} unless association.key?('data')
+          assoc_data = association['data']
+
           prefix_key = field_key(assoc_name, options).to_s.singularize
           hash =
             if assoc_data.is_a?(Array)
@@ -198,7 +206,7 @@ def parse_relationship(assoc_name, assoc_data, options)
         # @api private
         def parse_relationships(relationships, options)
           transform_keys(relationships, options)
-            .map { |(k, v)| parse_relationship(k, v['data'], options) }
+            .map { |(k, v)| parse_relationship(k, v, options) }
             .reduce({}, :merge)
         end
 

test/action_controller/json_api/deserialization_test.rb

@@ -106,6 +106,43 @@ def test_deserialization
 
           assert_equal(expected, response)
         end
+
+        def test_deserialization_with_links_relationship
+          hash = {
+            'data' => {
+              'type' => 'photos',
+              'id' => 'zorglub',
+              'attributes' => {
+                'title' => 'Ember Hamster',
+                'src' => 'http://example.com/images/productivity.png',
+                'image-width' => '200',
+                'imageHeight' => '200',
+                'ImageSize' => '1024'
+              },
+              'relationships' => {
+                'images' => {
+                  'links' => {
+                    'related' => 'https://example.com/images/tomster/related'
+                  }
+                }
+              }
+            }
+          }
+
+          post :render_parsed_payload, params: hash
+
+          response = JSON.parse(@response.body)
+          expected = {
+            'id' => 'zorglub',
+            'title' => 'Ember Hamster',
+            'src' => 'http://example.com/images/productivity.png',
+            'image_width' => '200',
+            'image_height' => '200',
+            'image_size' => '1024'
+          }
+
+          assert_equal(expected, response)
+        end
       end
     end
   end