恢复私有课程的公开资源不能引用问题（导致搜索速度慢）

app/helpers/files_helper.rb

@@ -107,7 +107,7 @@ module FilesHelper
   def visable_attachemnts_insite attachments,course
     result = []
     attachments.each do |attachment|
-      if attachment_candown(attachment) || (attachment.container_type == "Course" && attachment.container_id == course.id  && User.current.member_of_course?(Course.find(attachment.container_id)))|| attachment.author_id == User.current.id
+      if attachment.is_public? || (attachment.container_type == "Course" && attachment.container_id == course.id  && User.current.member_of_course?(Course.find(attachment.container_id)))|| attachment.author_id == User.current.id
         result << attachment
       end
     end