Change root json decode patch to patch only 3.0.x versions

Root encode fix now properly limited to ShopifyAPI Base classes
only instead of overwriting Rails module functionality for any
project that includes this gem. Our previous soluction was ignoring
the system-wide include_root_in_json setting that wasn't
explicitly set in the to_json options.

lib/shopify_api/json_format.rb

@@ -1,39 +1,16 @@
 module ActiveResource
-  class Base
-    def encode(options = {})
-      same = dup
-      same.attributes = {self.class.element_name => same.attributes} if self.class.format.extension == 'json'
-      
-      same.send("to_#{self.class.format.extension}", options)
-    end
-  end
-
-  module Formats
-    module JsonFormat
-      def decode(json)
-        data = ActiveSupport::JSON.decode(json)
-        if data.is_a?(Hash) && data.keys.size == 1
-          data.values.first
-        else
-          data
-        end
-      end
-    end
-  end
-end
-
-module ActiveModel
-  module Serializers
-    module JSON
-      def as_json(options = nil)
-        root = options[:root] if options.try(:key?, :root)
-        if include_root_in_json
-          root = self.class.model_name.element if root == true
-          { root => serializable_hash(options) }
-        else
-          serializable_hash(options)
+  if ActiveResource::VERSION::STRING =~ /^3\.0\./
+    module Formats
+      module JsonFormat
+        def decode(json)
+          data = ActiveSupport::JSON.decode(json)
+          if data.is_a?(Hash) && data.keys.size == 1
+            data.values.first
+          else
+            data
+          end
         end
       end
     end
   end
-end
+end

lib/shopify_api/resources/base.rb

@@ -34,9 +34,23 @@ module ShopifyAPI
       !id.nil?
     end
 
+    def encode(options = {})
+      obj = dup
+
+      if self.class.format.extension == 'json' && !already_has_root_element?(obj.attributes)
+        obj.attributes = {self.class.element_name => obj.attributes}
+      end
+
+      obj.send("to_#{self.class.format.extension}", options)
+    end
     private
     def only_id
       encode(:only => :id, :include => [], :methods => [])
     end
+
+    def already_has_root_element?(attributes)
+      attributes.keys.size == 1 && attributes.values.first.kind_of?(Hash)
+    end
   end
 end
+