Serialize just attributes

lib/active_model/serializer.rb

@@ -0,0 +1,43 @@
+module ActiveModel
+  class Serializer
+    class << self
+      def inherited(base)
+        base._attributes = {}
+      end
+
+      attr_accessor :_attributes
+
+      def attributes(*attrs)
+        @_attributes = attrs.map(&:to_s)
+
+        attrs.each do |attr|
+          define_method attr do
+            object.read_attribute_for_serialization(attr)
+          end
+        end
+      end
+    end
+
+    def initialize(object)
+      @object = object
+    end
+    attr_accessor :object
+
+    alias read_attribute_for_serialization send
+
+    def attributes
+      self.class._attributes.each_with_object({}) do |name, hash|
+        hash[name] = send(name)
+      end
+    end
+
+    def serializable_hash(options={})
+      return nil if object.nil?
+      attributes
+    end
+
+    def as_json(options={})
+      serializable_hash
+    end
+  end
+end