CODEWITHSUNDEEP
javaservletsjakarta-ee
sarah
sarah

Reputation: 2397

Auto Log Off once the session expires

Our application logs off after 30 min and gets redirected to login page,i am specifying session timeout in web.xml and using a requestProcessor for redirecting.I want to show to the user a message saying your session got expired once the session expires,how can i do that.Auto log off ? I would like to prompt the error message on the page"The session is timeout, please login again" . Then how could I detect the session is timeout? will any methods trigger automatically?

Upvotes: 5

Views: 15960

Answers (5)

PraveenKumar Lalasangi
PraveenKumar Lalasangi

Reputation: 3523

Either it may be simple servlet, spring-mvc or spring-security auto logout is not possible without perfect client side logic.
Considering application will have both type of request

  • AJAX and
  • form submission/page reload

Auto logout needs very calculated logic. Presenting my autologout functionality implementation with following

Advantages.

1. No extra call/request is used to achieve this. considering performance impact if more than 10k active users and extra calls to achieve auto logout.
2. One line configuration using tag.
3. Works flawlessly even if user opens multiple tab or multiple window.
4. It intimates you before 30 seconds of session invalidation, so if you have filled form and not submitted, you can keep session alive(extend session by one click). So user less likely to loose unsaved data.

Usage

1. Include auto logout script in required JSP pages as given below.

    ....
    </body>
    <jsp:include page="../template/autologout-script.jsp"></jsp:include>
</html>

2. Create a JSP page, autologout-script.jsp and add below code. Note: No editing/configuring is required

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<script>
$(document).ready(function()
{
    var timeOutTimeInSeconds = ${ timeOutTimeInSeconds }; 
    var showTimerTimeInSeconds= ${ showTimerTimeInSeconds };

    var sessionCheckIntervalId = setInterval(redirectToLoginPage, timeOutTimeInSeconds * 1000);
    var timerDisplayIntervalId = setInterval(showTimer, (timeOutTimeInSeconds - showTimerTimeInSeconds) * 1000);
    var badgeTimerId;
    window.localStorage.setItem("AjaxRequestFired", new Date());

    function redirectToLoginPage(){
        //location.href =  '<c:url value="/" />'+'${loginPageUrl}';
        window.location.reload();
    }

    $(document).ajaxComplete(function () {
        resetTimer();
    });

    $(window).bind('storage', function (e) {
         if(e.originalEvent.key == "AjaxRequestFired"){
             console.log("Request sent from another tab, hence resetting timer")
             resetTimer();
         }
    });

    function resetTimer()
    {
        showTimerTimeInSeconds= ${ showTimerTimeInSeconds };

        console.log("timeOutTimeInSeconds : "+timeOutTimeInSeconds)
        window.localStorage.setItem("AjaxRequestFired", new Date());

        window.clearInterval(sessionCheckIntervalId);
        sessionCheckIntervalId = setInterval(redirectToLoginPage, timeOutTimeInSeconds * 1000);

        window.clearInterval(timerDisplayIntervalId);
        timerDisplayIntervalId = setInterval(showTimer, (timeOutTimeInSeconds - showTimerTimeInSeconds) * 1000);

        hideTimer();
    }

    function showTimer()
    {
        $('#sessionTimeRemaining').show();
        $('#sessionTimeRemainingBadge').html(showTimerTimeInSeconds--);
        window.clearInterval(timerDisplayIntervalId);
        badgeTimerId = setInterval(function(){
            $('#sessionTimeRemainingBadge').html(showTimerTimeInSeconds--);
        }, 1000);
    }

    function hideTimer()
    {
        window.clearInterval(badgeTimerId);
        $('#sessionTimeRemaining').hide();
    }
});
</script>

3. Configure session attributes to configuring timeout setting Note: Configure this after session creation. You can implement HttpSessionListener sessionCreated method and set the following configuration as per your requirement.

session.setMaxInactiveInterval(300);

session.setAttribute("timeOutTimeInSeconds", 300);
session.setAttribute("showTimerTimeInSeconds", 30);

4. Add below html for displaying timer.
Note: it can be moved to autologout-script template page if you are good at CSS. Hence you can avoid to add this in each and every page.
Include bootstrap or add your custom css.

<span class="badge badge-primary" title="click to keep session alive" id="sessionTimeRemaining" 
    onclick="ajaxSessionRefresh()" style="display:none;">
    <i class="badge badge-danger" id="sessionTimeRemainingBadge" style="float:left">30</i>
     &nbsp; 
     <small>Refresh</small>
     <i class="glyphicon glyphicon-refresh"></i>
</span>

enter image description here

That is all about a simple auto logout implementation. You can download working example from my github repository
Autologout using simple servlet example
Autologout using spring-security java configuration example
Autologout using spring-security xml configuration example

Logic Explained

Case 1: On Page load
Here logic is simple, on page load set timer of interval equlas to maxInactiveInterval. after timeout redirect to login page.
Case 2: Keep track AJAX calls
Now considering AJAX requests, you can use .ajaxStart() or .ajaxComplete() callbacks of jquery so that if any ajax request is fired you can reset the interval.
Case 3: Tracking multi tab/window activity
Intertab communication is done to synchronize state of each tab. Used localStorage on change event.

Limitations/Improvements required
1. If maximum allowed session is one, if session is taken from another system, AJAX request will fail. It needs to be handled to redirect to login page.
2. Use ajaxStart() instead of ajaxComplete() to have exact sync of idleTime values between server and browser.

Requirements
1. Jquery

Alternatives to current implementation compared

1. Setting Refresh header in http response. (Not works for AJAX requests)

response.setHeader("Refresh", "60; URL=login.jsp");
  1. Setting meta refresh tag in HTML (Not works for AJAX requests)
<meta http-equiv="refresh" content="60; url=login.jsp">
  1. Configuring Activity checker Keeps session alive by repeated AJAX request. Tracks idle time and makes logout request after timeout.
    No doubt it is a good one with simple logic. But i want to just ink my observations.
    • Performance impact if 2 requests are made per minute to keep session alive and 50k active users. 100k requests per minute.
    • Intertab communication If two tabs are open, one tab is receiving activity but other tab is not receiving activity, that tab fires logout request and invalidate session even though activity is present in other tab. (But can be handled)
    • Force logout approach It is a client is dominated over server to invalidate session.

Upvotes: 1

BalusC
BalusC

Reputation: 1108642

Create an activity checker which checks every minute if any user activity has taken place (mouseclick, keypress) and performs a heartbeat to the server side to keep the session alive when the user is active and does nothing when the user is not active. When there is no activity for 30 minutes (or whatever default session timeout is been set on server side), then perform a redirect.

Here's a kickoff example with little help of jQuery to bind click and keypress events and fire ajax request.

<script src="http://code.jquery.com/jquery-latest.min.js"></script>
<script>
    $(document).ready(function() {
        $.active = false;
        $('body').bind('click keypress', function() { $.active = true; });
        checkActivity(1800000, 60000, 0); // timeout = 30 minutes, interval = 1 minute.
    });

    function checkActivity(timeout, interval, elapsed) {
        if ($.active) {
            elapsed = 0;
            $.active = false;
            $.get('heartbeat');
        }
        if (elapsed < timeout) {
            elapsed += interval;
            setTimeout(function() {
                checkActivity(timeout, interval, elapsed);
            }, interval);
        } else {
            window.location = 'http://example.com/expired'; // Redirect to "session expired" page.
        }
    }
</script>

Create a Servlet which listens on /heartbeat and does basically just the following:

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) {
    request.getSession();
}

to keep the session alive.

When you store the logged-in user in the session, it will be "automagically" logged out whenever the session expires. So you don't need to manually logout the user.

Upvotes: 11

Script Runner
Script Runner

Reputation: 282

Include a javascript utility function inside your JSP and ping the server every 31 minutes. The above mentioned utility function should be using setTimeout() JS function internally.

setTimeout ( "checkServerSession()",  /* intervalInMilliSeconds */ 31000);

Note that

checkServerSession()

is a regular JS function which may fire HTTP requests. If the request is successful session exists otherwise show the prompt to the user.

Upvotes: 0

JoseK
JoseK

Reputation: 31371

Create a Listener class implementing HttpSessionListener and define it in web.xml

This will notify you when any session is destroyed. Use the sessionDestroyed() method.

See a full example here:

http://www.mkyong.com/servlet/a-simple-httpsessionlistener-example-active-sessions-counter/

Upvotes: 2

futureelite7
futureelite7

Reputation: 11502

If you're using servlet sessions, you can check to see if the session the jsp / servlet is returning is new using the isNew() method. If yes, then the user's session has expired and you can display the relevant messages.

Upvotes: 0

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