How Can I Prevent Premature ASP.NET Session Expiration Due to Inactivity?

Prolonging ASP.NET Sessions: A Practical Approach

Maintaining active user sessions is vital for seamless web application experiences. Premature session expiry due to inactivity can disrupt workflows and lead to data loss. This article presents a solution using timed AJAX calls to prevent this common issue.

Keeping Sessions Alive with AJAX

Periodically sending HTTP requests to the server effectively refreshes the session's timestamp, preventing expiration. This lightweight method minimizes disruption to user interaction.

Implementing a Session Refresh Handler

A simple HTTP handler processes GET requests and updates the session timestamp. Here's a basic implementation:

public class SessionHeartbeatHttpHandler : IHttpHandler, IRequiresSessionState
{
    public bool IsReusable { get { return false; } }

    public void ProcessRequest(HttpContext context)
    {
        context.Session["Heartbeat"] = DateTime.Now;
    }
}

Register this handler in your web.config:

<httpHandlers>
  <add path="SessionHeartbeat.ashx" type="SessionHeartbeatHttpHandler" validate="false" verb="GET,HEAD" />
</httpHandlers>

JavaScript for Scheduled AJAX Calls

Client-side JavaScript executes timed AJAX calls to the SessionHeartbeat.ashx handler. This jQuery example demonstrates the process:

function setHeartbeat() {
    setTimeout("heartbeat()", 5*60*1000); // Every 5 minutes
}

function heartbeat() {
    $.get(
        "/SessionHeartbeat.ashx",
        null,
        function(data) {
            //$("#heartbeat").show().fadeOut(1000); // Optional visual feedback
            setHeartbeat();
        },
        "json"
    );
}

Adding Visual Feedback (Optional)

Enhance user experience by incorporating a visual indicator, such as a pulsating icon, to confirm session refresh. This example uses a heart icon:

// Animate a heart icon
function beatHeart(times) {
    var interval = setInterval(function () {
        $(".heartbeat").fadeIn(500).fadeOut(500);
    }, 1000); // Beat every second
    setTimeout(function () { clearInterval(interval); }, (1000 * times) + 100);
}

Summary

Employing timed AJAX calls to a dedicated handler provides a robust and unobtrusive method for maintaining active ASP.NET sessions. This simple technique prevents premature session expiry, ensuring a smooth and uninterrupted user experience.

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