.

app/controllers/wechats_controller.rb

@@ -189,9 +189,9 @@ class WechatsController < ActionController::Base
 
   def join_class(params, user)
     course = nil
-    course = Course.where(qrcode: params[:ticket]) if params[:ticket]
-    course = Course.where(invite_code: params[:invite_code]) if params[:invite_code]
-    raise "课程不存在" if course.blank?
+    course = Course.where(qrcode: params[:ticket]).first if params[:ticket]
+    course = Course.where(invite_code: params[:invite_code]).first if params[:invite_code]
+    raise "课程不存在" unless course
 
     cs = CoursesService.new
     status = cs.join_course(course.invite_code, user)
@@ -200,7 +200,6 @@ class WechatsController < ActionController::Base
       raise CoursesService::JoinCourseError.message(status[:state])
     end
 
-    course = status[:course]
     news = (1..1).each_with_object([]) { |n, memo| memo << { title: '恭喜您成功加入班级,开始学习吧!',
                                                              content: "课程名称: #{course.name}\n班级名称: #{course.name}\n任课老师: #{course.teacher.show_name}\n进入班级,和小伙伴愉快的学习吧!"} }
     return request.reply.news(news) do |article, n, index| # article is return object