如何判断给定的Devise用户是否已经登录？ [英] How can I tell whether a given Devise user is signed in right now?

问题描述

在使用Devise的Rails应用程序中，是否有一种方法来判断具体用户是否已登录 ？

In a Rails app that uses Devise, is there a way to tell if a specific user is signed in right now?

我知道视图助手， user_signed_in？。我正在寻找的更像是：

I know about the view helper, user_signed_in?. What I'm looking for is more like:

User.all.each do |user|
  puts user.signed_in?
end

我看到，Devise添加了一个 current_sign_in_at 列到用户。但是，当用户注销时，不会设置为 NULL ，所以我无法测试。

I see that Devise has added a current_sign_in_at column to users. But that doesn't get set to NULL when the user signs out, so I can't test with that.

如何检查用户当前是否已登录？

How can I check whether a user is currently signed in?

推荐答案

您可以添加 before_filter 到您的ApplicationController以在用户表中的 last_request_at 字段中设置当前日期/时间，您必须首先通过迁移添加。在从before_filter调用的方法中，您要确保用户首先被认证，当然。而您可能希望除了过滤器以外的操作不需要身份验证。

You can add a before_filter to your ApplicationController to set the current date/time in the last_request_at field in your users table, which you'd have to add first via a migration. In the method called from the before_filter, you wanna make sure that the user is authenticated first, of course. And you may want to except the filter for actions not requiring authentication.

然后，假设您已经在您的用户模型中包含了 Timeoutable 模块您可以通过以下方式查看用户的会话是否正在进行：

Then, assuming you've included the Timeoutable module in your User model, you can see if the user's session is current or not by making a call like this:

user.timedout?(user.last_request_at)

在Timeoutable中定义的 timedout（last_access）模块将会将Devise会话超时与最后一个请求时间/日期进行比较。

The timedout?(last_access) method, defined in the Timeoutable module, will compare the Devise session timeout with the last request time/date.

作为附注，如果最后一个last_request_at值更大，您可能只想更新last_request_at （或任何时间间隔您选择）。否则，如果您的页面进行了很多控制器调用，就像我通过AJAX一样，在一个请求中有很多不必要的数据库更新。

As a side note, you might want to only update last_request_at if the last last_request_at value is greater than a minute ago (or any time interval you choose). Otherwise, if your page makes lots of controller calls, like mine does via AJAX, there are a lot of unnecessary db updates in one request.

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