From 08716d20c91d321b69e8b3720efdb7c5c4ecb7ec Mon Sep 17 00:00:00 2001
From: Gary Gordon <gfgordon@gmail.com>
Date: Thu, 6 Nov 2014 11:10:15 -0500
Subject: [PATCH] Rename attribute with :key (0.8.x compatibility)

---
 README.md                          | 12 ++++++++++++
 lib/active_model/serializer.rb     |  9 ++++++++-
 test/fixtures/poro.rb              |  5 +++++
 test/serializers/attribute_test.rb | 23 +++++++++++++++++++++++
 4 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 test/serializers/attribute_test.rb

diff --git a/README.md b/README.md
index 1d9db323..6bb70f3a 100644
--- a/README.md
+++ b/README.md
@@ -69,6 +69,18 @@ ActiveModel::Serializer.config.adapter = :hal
 You won't need to implement an adapter unless you wish to use a new format or
 media type with AMS.
 
+If you would like the key in the outputted JSON to be different from its name in ActiveRecord, you can use the :key option to customize it:
+
+```ruby
+class PostSerializer < ActiveModel::Serializer
+  attributes :id, :body
+
+  # look up :subject on the model, but use +title+ in the JSON
+  attribute :subject, :key => :title
+  has_many :comments
+end
+```
+
 In your controllers, when you use `render :json`, Rails will now first search
 for a serializer for the object and use it if available.
 
diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index dbc2060d..9f9c91db 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -21,7 +21,6 @@ module ActiveModel
     def self.attributes(*attrs)
       @_attributes.concat attrs
 
-
       attrs.each do |attr|
         define_method attr do
           object.read_attribute_for_serialization(attr)
@@ -29,6 +28,14 @@ module ActiveModel
       end
     end
 
+    def self.attribute(attr, options = {})
+      key = options.fetch(:key, attr)
+      @_attributes.concat [key]
+      define_method key do
+        object.read_attribute_for_serialization(attr)
+      end unless method_defined?(key)
+    end
+
     # Defines an association in the object should be rendered.
     #
     # The serializer object should implement the association name
diff --git a/test/fixtures/poro.rb b/test/fixtures/poro.rb
index 4f584fed..f7c1becb 100644
--- a/test/fixtures/poro.rb
+++ b/test/fixtures/poro.rb
@@ -95,3 +95,8 @@ PaginatedSerializer = Class.new(ActiveModel::Serializer::ArraySerializer) do
     'paginated'
   end
 end
+
+AlternateBlogSerializer = Class.new(ActiveModel::Serializer) do
+  attribute :id
+  attribute :name, key: :title
+end
diff --git a/test/serializers/attribute_test.rb b/test/serializers/attribute_test.rb
new file mode 100644
index 00000000..35f27ee4
--- /dev/null
+++ b/test/serializers/attribute_test.rb
@@ -0,0 +1,23 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class AttributeTest < Minitest::Test
+      def setup
+        @blog = Blog.new({ id: 1, name: 'AMS Hints' })
+        @blog_serializer = AlternateBlogSerializer.new(@blog)
+      end
+
+      def test_attributes_definition
+        assert_equal([:id, :title],
+                     @blog_serializer.class._attributes)
+      end
+
+      def test_json_serializable_hash
+        adapter = ActiveModel::Serializer::Adapter::Json.new(@blog_serializer)
+        assert_equal({:id=>1, :title=>"AMS Hints"}, adapter.serializable_hash)
+      end
+    end
+  end
+end
+