<% if session[:current_user].blank? %>
     <%= link_to '登录', '/users/show_login_page', style: 'text-decoration: none; color: white;' %>
   <% elsif !session[:current_user].blank? %>
     <%= link_to '退出', '/users/logout', method: :delete, style: 'text-decoration: none; color: white;' %>
   <% end %>

<% if session[:current_user].blank? %>

修改为

<% if session[:current_user].blank? && request.host != "mysite.com" && request.host_with_port != "ha.mysite.com" && request.host_with_port != "hi.mysit.com:3000" %>