Add basic JSON serializer to AMo

2 files changed, 42 insertions, 0 deletions

diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index 048f542239..544121c593 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -38,6 +38,10 @@ module ActiveModel
   autoload :TestCase, 'active_model/test_case'
   autoload :Validations, 'active_model/validations'
   autoload :ValidationsRepairHelper, 'active_model/validations_repair_helper'
+
+  module Serializers
+    autoload :JSON, 'active_model/serializers/json'
+  end
 end
 
 I18n.load_path << File.dirname(__FILE__) + '/active_model/locale/en.yml'
diff --git a/activemodel/lib/active_model/serializers/json.rb b/activemodel/lib/active_model/serializers/json.rb
new file mode 100644
index 0000000000..60b5cbe948
--- /dev/null
+++ b/activemodel/lib/active_model/serializers/json.rb
@@ -0,0 +1,38 @@
+require 'active_support/json'
+require 'active_support/core_ext/class/attribute_accessors'
+require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/hash/slice'
+
+module ActiveModel
+  module Serializers
+    module JSON
+      extend ActiveSupport::Concern
+      include ActiveModel::Attributes
+
+      included do
+        cattr_accessor :include_root_in_json, :instance_writer => false
+      end
+
+      def encode_json(encoder)
+        options = encoder.options || {}
+
+        hash = if options[:only]
+          only = Array.wrap(options[:only]).map { |attr| attr.to_s }
+          attributes.slice(*only)
+        elsif options[:except]
+          except = Array.wrap(options[:except]).map { |attr| attr.to_s }
+          attributes.except(*except)
+        else
+          attributes
+        end
+
+        hash = { self.class.model_name.element => hash } if include_root_in_json
+        ActiveSupport::JSON.encode(hash)
+      end
+
+      def as_json(options = nil)
+        self
+      end
+    end
+  end
+end