某个页面跳入登录，登录成功后返回当前页面

app/controllers/application_controller.rb

@@ -577,19 +577,19 @@ class ApplicationController < ActionController::Base
   end
 
   def redirect_back_or_default(default, options={})
-    back_url = '' #params[:back_url].to_s
+    back_url = params[:back_url].to_s
     if back_url.present?
       begin
         uri = URI.parse(back_url)
         # do not redirect user to another host or to the login or register page
         if (uri.relative? || (uri.host == request.host)) && !uri.path.match(%r{/(login|account/register)})
-          back_url = back_url.gsub(%r{\/users\/(\d+)},"/users/"+default.id.to_s) if default.is_a?(:User)
+          back_url = back_url.gsub(%r{\/users\/(\d+)},"/users/"+default.id.to_s) if default.is_a?(User)
           redirect_to(back_url)
           return
         end
       rescue URI::InvalidURIError
         logger.warn("Could not redirect to invalid URL #{back_url}")
-        # redirect to default
+        redirect to default
       end
     elsif options[:referer]
       redirect_to_referer_or default