Tweak ActiveRecord::Base#to_json to include a root value in the retur…

…ned hash: {post: {title: ...}} [rick]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9202 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,11 @@
 *SVN*
 
+* Tweak ActiveRecord::Base#to_json to include a root value in the returned hash: {"post": {"title": ...}} [rick]
+
+  Post.find(1).to_json # => {"title": ...}
+  config.active_record.include_root_in_json = true
+  Post.find(1).to_json # => {"post": {"title": ...}}
+
 * Add efficient #include? to AssociationCollection (for has_many/has_many :through/habtm).  [stopdropandrew]
 
 * PostgreSQL: create_ and drop_database support.  #9042 [ez, pedz, nicksieger]

activerecord/lib/active_record/serializers/json_serializer.rb

@@ -1,5 +1,10 @@
 module ActiveRecord #:nodoc:
   module Serialization
+    def self.included(base)
+      base.cattr_accessor :include_root_in_json, :instance_writer => false
+      base.extend ClassMethods
+    end
+
     # Returns a JSON string representing the model. Some configuration is
     # available through +options+.
     #
@@ -48,7 +53,11 @@ module Serialization
     #                   {"comments": [{"body": "Don't think too hard"}],
     #                    "title": "So I was thinking"}]}
     def to_json(options = {})
-      JsonSerializer.new(self, options).to_s
+      if include_root_in_json
+        "{#{self.class.json_class_name}: #{JsonSerializer.new(self, options).to_s}}"
+      else
+        JsonSerializer.new(self, options).to_s
+      end
     end
 
     def from_json(json)
@@ -61,5 +70,11 @@ def serialize
         serializable_record.to_json
       end
     end
+
+    module ClassMethods
+      def json_class_name
+        @json_class_name ||= name.demodulize.underscore.inspect
+      end
+    end
   end
 end

activerecord/test/cases/json_serialization_test.rb

@@ -7,6 +7,10 @@
 require 'models/comment'
 
 class JsonSerializationTest < ActiveRecord::TestCase
+  class NamespacedContact < Contact
+    column :name,        :string
+  end
+
   def setup
     @contact = Contact.new(
       :name        => 'Konata Izumi',
@@ -18,6 +22,27 @@ def setup
     )
   end
 
+  def test_should_demodulize_root_in_json
+    NamespacedContact.include_root_in_json = true
+    @contact = NamespacedContact.new :name => 'whatever'
+    json = @contact.to_json
+    assert_match %r{^\{"namespaced_contact": \{}, json
+  end
+
+  def test_should_include_root_in_json
+    Contact.include_root_in_json = true
+    json = @contact.to_json
+
+    assert_match %r{^\{"contact": \{}, json
+    assert_match %r{"name": "Konata Izumi"}, json
+    assert_match %r{"age": 16}, json
+    assert json.include?(%("created_at": #{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
+    assert_match %r{"awesome": true}, json
+    assert_match %r{"preferences": \{"shows": "anime"\}}, json
+  ensure
+    Contact.include_root_in_json = false
+  end
+
   def test_should_encode_all_encodable_attributes
     json = @contact.to_json