.

app/controllers/wechats_controller.rb

@@ -16,7 +16,7 @@ class WechatsController < ActionController::Base
         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!"} }
         request.reply.news(news) do |article, n, index| # article is return object
-          url = "https://open.weixin.qq.com/connect/oauth2/authorize?appid=#{Wechat.config.appid}&redirect_uri=#{ROOT_URL+'/wechat/user_activities?id='+course.id}&response_type=code&scope=snsapi_base&state=myclass#wechat_redirect"
+          url = "https://open.weixin.qq.com/connect/oauth2/authorize?appid=#{Wechat.config.appid}&redirect_uri=#{ROOT_URL+'/wechat/user_activities?id='+course.id.to_s}&response_type=code&scope=snsapi_base&state=myclass#wechat_redirect"
           pic_url = "#{ROOT_URL}/images/wechat/class.jpg"
           article.item title: "#{n[:title]}",
                        description: n[:content],