课堂报错

app/helpers/application_helper.rb

@@ -140,11 +140,11 @@ module ApplicationHelper
   # 用户图像url，如果不存在的话，source为匿名用户，即默认使用匿名用户图像
   def url_to_avatar(source)
     if File.exist?(disk_filename(source&.class, source&.id))
-      ctime = File.ctime(disk_filename(source.class, source.id)).to_i
+      ctime = File.ctime(disk_filename(source&.class, source&.id)).to_i
       if source.class.to_s == 'User'
-        File.join(relative_path, ["#{source.class}", "#{source.id}"]) + "?t=#{ctime}"
+        File.join(relative_path, ["#{source&.class}", "#{source&.id}"]) + "?t=#{ctime}"
       else
-        File.join("images/avatars", ["#{source.class}", "#{source.id}"]) + "?t=#{ctime}"
+        File.join("images/avatars", ["#{source&.class}", "#{source&.id}"]) + "?t=#{ctime}"
       end
     elsif source.class.to_s == 'User'
       str = source.user_extension.try(:gender).to_i == 0 ? "b" : "g"

app/views/courses/index.json.jbuilder

@@ -2,7 +2,7 @@ json.courses @courses do |course|
     json.id course.id
     json.name course.name
     json.avatar_url url_to_avatar(course.teacher)
-    json.creator course.teacher.real_name
+    json.creator course.teacher&.real_name
     json.school course.school&.name
     json.technical_title "" # course.teacher.identity
     json.course_members_count course.course_members_count