保持会话无限期的存活 [英] Keep a session alive for an indefinite amount of time

问题描述

是否有一种方法可以使页面的会话保持活动状态，而无需诉诸状态发送给客户端?我无法将STATE_SAVING_METHOD设置为client，并且我不想使用a4j:keepalive.

Is there a way to keep a page's session active without resorting to sending the state to the client? I'm not able to set the STATE_SAVING_METHOD to client and I'd prefer to not use the a4j:keepalive.

我尝试使用一个简单的隐藏iframe提交给有问题的Bean，但是它会使主页无效.

I've tried using a simple hidden iframe that submits to the Bean in question but it invalidates the main page.

我正在使用JSF 1.2和myfaces.

I am using JSF 1.2 and myfaces.

这是为了避免在不需要用户登录的页面上发生ViewExpiredException.大多数现有站点都需要用户登录.

This is to get around a ViewExpiredException on a page that does not require the user to log in. The majority of the existing site requires the user to log in.

推荐答案

将ajax轮询作为心跳"实施，以使会话保持活动状态.最简单的方法是，在一些 jQuery 的帮助下，可以达到以下目的，从而避免了100行的样板代码才能使其正常工作世界各地的所有不同浏览器都知道:

Implement an ajax poll as a "heartbeat" to keep the session alive. At its simplest you can achieve this as follows with help of a little jQuery to avoid boilerplate code of 100 lines to get it to work across all different browsers the world is aware of:

<script src="http://code.jquery.com/jquery-latest.min.js"></script>
<script>
    $(document).ready(function() {
        setInterval(function() {
            $.get("${pageContext.request.contextPath}/poll");
        }, ${(pageContext.session.maxInactiveInterval - 10) * 1000});
    });
</script>

${pageContext.session.maxInactiveInterval} 根据服务器端的配置(会话可以通过web.xml中的<session-timeout>控制的方式)显示会话尚待运行的剩余秒数，并扣除10秒，只是为了准时它会自动过期，并转换为毫秒，以适应 setInterval() 的期望.

The ${pageContext.session.maxInactiveInterval} prints the remaining seconds the session has yet to live according to the server side configuration (which is by the way controllable by <session-timeout> in web.xml) and is been deducted with 10 seconds, just to be on time before it automatically expires, and converted to milliseconds so that it suits what setInterval() expects.

$.get() 在给定的URL上发送ajax GET请求.对于上面的示例，您需要在/poll的URL模式上映射servlet，并且基本上在doGet()方法中执行以下操作:

The $.get() sends an ajax GET request on the given URL. For the above example, you need to map a servlet on the URL pattern of /poll and does basically the following in the doGet() method:

request.getSession(); // Keep session alive.

应该的.

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