Implement meta and meta_key for AM::Serializer

lib/active_model/serializer.rb

@@ -28,12 +28,14 @@ module ActiveModel
     end
 
     def initialize(object, options={})
-      @object = object
-      @root   = options[:root] || self.class._root
-      @root   = self.class.root_name if @root == true
-      @scope  = options[:scope]
+      @object   = object
+      @root     = options[:root] || self.class._root
+      @root     = self.class.root_name if @root == true
+      @scope    = options[:scope]
+      @meta_key = options[:meta_key] || :meta
+      @meta     = options[@meta_key]
     end
-    attr_accessor :object, :root, :scope
+    attr_accessor :object, :root, :scope, :meta_key, :meta
 
     alias read_attribute_for_serialization send
 
@@ -50,7 +52,9 @@ module ActiveModel
 
     def as_json(options={})
       if root = options[:root] || self.root
-        { root.to_s => serializable_hash }
+        hash = { root.to_s => serializable_hash }
+        hash[meta_key.to_s] = meta if meta
+        hash
       else
         serializable_hash
       end

test/unit/active_model/serializer/meta_test.rb

@@ -0,0 +1,41 @@
+require 'newbase/test_helper'
+require 'newbase/active_model/serializer'
+
+
+module ActiveModel
+  class Serializer
+    class MetaTest < ActiveModel::TestCase
+      def setup
+        @model = Model.new({ :attr1 => 'value1', :attr2 => 'value2', :attr3 => 'value3' })
+      end
+
+      def test_meta
+        model_serializer = ModelSerializer.new(@model, root: 'model', meta: { 'total' => 10 })
+
+        assert_equal({
+          'model' => {
+            'attr1' => 'value1',
+            'attr2' => 'value2'
+          },
+          'meta' => {
+            'total' => 10
+          }
+        }, model_serializer.as_json)
+      end
+
+      def test_meta_using_meta_key
+        model_serializer = ModelSerializer.new(@model, root: 'model', meta_key: :my_meta, my_meta: { 'total' => 10 })
+
+        assert_equal({
+          'model' => {
+            'attr1' => 'value1',
+            'attr2' => 'value2'
+          },
+          'my_meta' => {
+            'total' => 10
+          }
+        }, model_serializer.as_json)
+      end
+    end
+  end
+end