Extract Association login into AssociationConfiguration

lib/active_model/serializer.rb

@@ -68,9 +68,9 @@ module ActiveModel
 
     attr_accessor :object, :configuration
 
-    def initialize(object, options = {})
+    def initialize(object, options = {}, configuration = nil)
       @object        = object
-      @configuration = InstanceConfiguration.new self.class.configuration, options
+      @configuration = InstanceConfiguration.new(configuration || self.class.configuration, options)
     end
 
     def json_key
@@ -92,9 +92,9 @@ module ActiveModel
       included_associations = filter(associations.keys)
       associations.each_with_object({}) do |(name, association), hash|
         if included_associations.include? name
-          if association.embed_ids?
+          if association.embed_ids
             hash[association.key] = serialize_ids association
-          elsif association.embed_objects?
+          elsif association.embed_objects
             hash[association.embedded_key] = serialize association
           end
         end
@@ -110,7 +110,7 @@ module ActiveModel
       included_associations = filter(associations.keys)
       associations.each_with_object({}) do |(name, association), hash|
         if included_associations.include? name
-          if association.embed_in_root?
+          if association.embed_in_root
             association_serializer = build_serializer(association)
             hash.merge! association_serializer.embedded_in_root_associations
 

lib/active_model/serializer/associations.rb

@@ -4,6 +4,8 @@ require 'active_model/serializer'
 module ActiveModel
   class Serializer
     class Association
+      attr_accessor :name, :configuration
+
       def initialize(name, options = {}, configuration = nil)
         if options.has_key?(:include)
           ActiveSupport::Deprecation.warn <<-WARN
@@ -13,28 +15,25 @@ module ActiveModel
         end
 
         @name          = name.to_s
-        @options       = options
-        self.embed     = options.fetch(:embed) { configuration.embed }
-        @embed_in_root = options.fetch(:embed_in_root) { configuration.embed_in_root }
-        @embed_key     = options[:embed_key] || :id
-        @key           = options[:key]
-        @embedded_key  = options[:root] || name
-
-        serializer = @options[:serializer]
-        @serializer_from_options = serializer.is_a?(String) ? serializer.constantize : serializer
+        @configuration = AssociationConfiguration.new configuration, options
       end
 
-      attr_reader :name, :embed_ids, :embed_objects
-      attr_accessor :embed_in_root, :embed_key, :key, :embedded_key, :root_key, :serializer_from_options, :options
-      alias embed_ids? embed_ids
-      alias embed_objects? embed_objects
-      alias embed_in_root? embed_in_root
+      extend Forwardable
+      def_delegators :configuration, :embed_ids, :embed_objects, :embed, :embed_in_root, :embed_key, :key, :root, :serializer
+
+      def embedded_key
+        root || name
+      end
 
       def embed=(embed)
         @embed_ids     = embed == :id || embed == :ids
         @embed_objects = embed == :object || embed == :objects
       end
 
+      def serializer_from_options
+        configuration.serializer
+      end
+
       def serializer_from_object(object)
         Serializer.serializer_for(object)
       end
@@ -44,14 +43,16 @@ module ActiveModel
       end
 
       def build_serializer(object, options = {})
-        serializer_class(object).new(object, options.merge(self.options))
+        serializer_class(object).new(object, options, configuration)
       end
 
       class HasOne < Association
-        def initialize(name, *args)
-          super
-          @root_key = @embedded_key.to_s.pluralize
-          @key ||= "#{name}_id"
+        def root_key
+          embedded_key.to_s.pluralize
+        end
+
+        def key
+          "#{name}_id"
         end
 
         def serializer_class(object)
@@ -60,16 +61,16 @@ module ActiveModel
 
         def build_serializer(object, options = {})
           super.tap do |instance|
-            instance.configuration.wrap_in_array = embed_in_root?
+            instance.configuration.wrap_in_array = embed_in_root
           end
         end
       end
 
       class HasMany < Association
-        def initialize(name, *args)
-          super
-          @root_key = @embedded_key
-          @key ||= "#{name.to_s.singularize}_ids"
+        alias_method :root_key, :embedded_key
+
+        def key
+          "#{name.to_s.singularize}_ids"
         end
 
         def serializer_class(object)
@@ -80,9 +81,9 @@ module ActiveModel
           end
         end
 
-        def options
+        def build_serializer(object, options = {})
           if use_array_serializer?
-            { each_serializer: serializer_from_options }.merge! super
+            super object, { each_serializer: serializer_from_options }.merge!(options), configuration
           else
             super
           end

lib/active_model/serializer/configuration.rb

@@ -115,5 +115,25 @@ module ActiveModel
         { embed: :objects, meta_key: :meta }
       end
     end
+
+    class AssociationConfiguration < Configuration
+      options :embed, :embed_in_root, :embed_key, :key, :root, :serializer
+
+      def default_options
+        { embed_key: :id }
+      end
+
+      def serializer=(value)
+        @serializer = value.is_a?(String) ? value.constantize : value
+      end
+
+      def embed_objects
+        [:objects, :object].include? embed
+      end
+
+      def embed_ids
+        [:ids, :id].include? embed
+      end
+    end
   end
 end