onemanstartup · January 11, 2015 06:42 · Jan 11, 2015
diff --git a/json_accessor.rb b/json_accessor.rb
@@ -0,0 +1,44 @@
+# You don't actually need this.
+# I wrote this, but rails support this 
+# Use store_accessor :data, :admin
+
+module JsonAccessor
+  extend ActiveSupport::Concern
+
+  module ClassMethods
+    def json_accessor(json_attribute, *fields)
+      send(:store, json_attribute, accessors: fields)
+
+      field_methods = Module.new
+      fields.each do |any_key|
+        key = any_key.to_s.freeze
+
+        field_methods.send(:define_method, "#{key}_changed?") do
+          send("#{key}_change").present?
+        end
+
+        field_methods.send(:define_method, "#{key}_will_change!") do
+          send("#{json_attribute}_will_change!")
+        end
+
+        field_methods.send(:define_method, "#{key}_was") do
+          (send(:attribute_was, json_attribute) || {})[key]
+        end
+
+        field_methods.send(:define_method, "#{key}_change") do
+          json_changes = send("#{json_attribute}_change")
+          return if json_changes.nil?
+          attribute_changes = json_changes.map { |change| change.try(:[], key.to_s) }
+          attribute_changes.compact.present? ? attribute_changes : nil
+        end
+
+        field_methods.send(:define_method, "restore_#{key}!") do
+          old_json = send("#{json_attribute}_change").try(:first) || {}
+          send("#{key}=", old_json[key.to_s])
+        end
+
+        include field_methods
+      end
+    end
+  end
+end