Block syntax for associations.

lib/active_model/serializer/associations.rb

@@ -13,9 +13,8 @@ module Associations
       DEFAULT_INCLUDE_TREE = ActiveModel::Serializer::IncludeTree.from_string('*')
 
       included do |base|
-        class << base
-          attr_accessor :_reflections
-        end
+        base.class_attribute :_reflections
+        base._reflections ||= []
 
         extend ActiveSupport::Autoload
         autoload :Association
@@ -29,58 +28,44 @@ class << base
 
       module ClassMethods
         def inherited(base)
-          base._reflections = self._reflections.try(:dup) || []
+          super
+          base._reflections = _reflections.dup
         end
 
         # @param [Symbol] name of the association
         # @param [Hash<Symbol => any>] options for the reflection
+        # @param [Block] optional block to customize value of the reflection
         # @return [void]
         #
         # @example
         #  has_many :comments, serializer: CommentSummarySerializer
         #
-        def has_many(name, options = {})
-          associate HasManyReflection.new(name, options)
+        def has_many(name, options = {}, &block)
+          _reflections << HasManyReflection.new(name, options, block)
         end
 
         # @param [Symbol] name of the association
         # @param [Hash<Symbol => any>] options for the reflection
+        # @param [Block] optional block to customize value of the reflection
         # @return [void]
         #
         # @example
         #  belongs_to :author, serializer: AuthorSerializer
         #
-        def belongs_to(name, options = {})
-          associate BelongsToReflection.new(name, options)
+        def belongs_to(name, options = {}, &block)
+          _reflections << BelongsToReflection.new(name, options, block)
         end
 
         # @param [Symbol] name of the association
         # @param [Hash<Symbol => any>] options for the reflection
+        # @param [Block] optional block to customize value of the reflection
         # @return [void]
         #
         # @example
         #  has_one :author, serializer: AuthorSerializer
         #
-        def has_one(name, options = {})
-          associate HasOneReflection.new(name, options)
-        end
-
-        private
-
-        # Add reflection and define {name} accessor.
-        # @param [ActiveModel::Serializer::Reflection] reflection
-        # @return [void]
-        #
-        # @api private
-        #
-        def associate(reflection)
-          self._reflections = _reflections.dup
-
-          define_method reflection.name do
-            object.send reflection.name
-          end unless method_defined?(reflection.name)
-
-          self._reflections << reflection
+        def has_one(name, options = {}, &block)
+          _reflections << HasOneReflection.new(name, options, block)
         end
       end
 

lib/active_model/serializer/reflection.rb

@@ -17,7 +17,7 @@ class Serializer
     #
     # So you can inspect reflections in your Adapters.
     #
-    Reflection = Struct.new(:name, :options) do
+    Reflection = Struct.new(:name, :options, :proc) do
       # Build association. This method is used internally to
       # build serializer's association by its reflection.
       #
@@ -40,7 +40,11 @@ class Serializer
       # @api private
       #
       def build_association(subject, parent_serializer_options)
-        association_value = subject.send(name)
+        association_value = if proc.nil?
+                              subject.object.send(name)
+                            else
+                              subject.instance_eval(&proc)
+                            end
         reflection_options = options.dup
         serializer_class = subject.class.serializer_for(association_value, reflection_options)
 
@@ -54,7 +58,7 @@ def build_association(subject, parent_serializer_options)
             reflection_options[:virtual_value] = association_value.try(:as_json) || association_value
           end
         elsif !association_value.nil? && !association_value.instance_of?(Object)
-          reflection_options[:virtual_value] = association_value
+          reflection_options[:virtual_value] = association_value.try(:as_json) || association_value
         end
 
         Association.new(name, serializer, reflection_options)

test/adapter/json_api/has_many_test.rb

@@ -132,8 +132,8 @@ def test_has_many_with_virtual_value
                 id: '1',
                 type: 'virtual_values',
                 relationships: {
-                  maker: { data: { id: 1 } },
-                  reviews: { data: [{ id: 1 }, { id: 2 }] }
+                  maker: { data: { 'id' => 1 } },
+                  reviews: { data: [{ 'id' => 1 }, { 'id' => 2 }] }
                 }
               }
             }, adapter.serializable_hash)

test/adapter/json_api/has_one_test.rb

@@ -66,8 +66,8 @@ def test_has_one_with_virtual_value
                 id: '1',
                 type: 'virtual_values',
                 relationships: {
-                  maker: { data: { id: 1 } },
-                  reviews: { data: [{ id: 1 }, { id: 2 }] }
+                  maker: { data: { 'id' => 1 } },
+                  reviews: { data: [{ 'id' => 1 }, { 'id' => 2 }] }
                 }
               }
             }

test/fixtures/poro.rb

@@ -62,12 +62,10 @@ module Spam; end
   attributes :id, :title, :body
 
   has_many :comments
-  belongs_to :blog
-  belongs_to :author
-
-  def blog
+  belongs_to :blog do
     Blog.new(id: 999, name: 'Custom blog')
   end
+  belongs_to :author
 
   def custom_options
     instance_options
@@ -124,9 +122,7 @@ def slug
 
 LocationSerializer = Class.new(ActiveModel::Serializer) do
   cache only: [:place], skip_digest: true
-  attributes :id, :lat, :lng
-
-  belongs_to :place
+  attributes :id, :lat, :lng, :place
 
   def place
     'Nowhere'
@@ -212,13 +208,11 @@ def self.root_name
 VirtualValueSerializer = Class.new(ActiveModel::Serializer) do
   attributes :id
 
-  has_many :reviews, virtual_value: [{ id: 1 }, { id: 2 }]
-  has_one :maker, virtual_value: { id: 1 }
-
-  def reviews
+  has_many :reviews do
+    [{ id: 1 }, { id: 2 }]
   end
-
-  def maker
+  has_one :maker do
+    { id: 1 }
   end
 end