How To implement auto-logout functionality at the Tomcat server level

To implement auto-logout functionality at the Tomcat server level, you can configure session timeout settings. This ensures that inactive users are logged out after a specified period. Here’s how you can do it:

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1. Configure Session Timeout in web.xml

• The web.xml file (Deployment Descriptor) defines application-wide session timeout.
• Set the timeout in minutes using the <session-config> tag.

Steps:

1. Open the web.xml file located in your application's WEB-INF directory.
2. Add or modify the <session-config> section:

<session-config>
    <session-timeout>30</session-timeout> <!-- Timeout after 30 minutes -->
</session-config>

• 30 is the timeout duration in minutes. Change it as required.
• After the timeout, inactive sessions will be invalidated.

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2. Enforce Session Timeout Programmatically (Optional)

If you need dynamic control over session timeouts, set it programmatically within your application.

Example in a Servlet:

HttpSession session = request.getSession();
session.setMaxInactiveInterval(1800); // 1800 seconds = 30 minutes

• This sets the timeout to 30 minutes for the specific session.

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3. Global Timeout for All Applications

To apply session timeout for all web applications running on a Tomcat server:

1. Edit the web.xml file in Tomcat’s conf directory (e.g., TOMCAT_HOME/conf/web.xml).
2. Add or modify <session-config>:

<session-config>
    <session-timeout>30</session-timeout> <!-- Timeout for all apps -->
</session-config>

• This will be applied to all deployed applications unless overridden in their specific web.xml.

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4. Configure Session Expiry Logging

To log session expiration events, you can use a session listener.

Example HttpSessionListener Implementation:

1. Create a listener class:

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

public class SessionTimeoutListener implements HttpSessionListener {
    @Override
    public void sessionCreated(HttpSessionEvent event) {
        System.out.println("Session Created: " + event.getSession().getId());
    }

    @Override
    public void sessionDestroyed(HttpSessionEvent event) {
        System.out.println("Session Destroyed: " + event.getSession().getId());
    }
}

2. Register the listener in web.xml:

<listener>
    <listener-class>com.example.SessionTimeoutListener</listener-class>
</listener>

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5. Auto-Logout at Browser Level

To complement server-level auto-logout, implement client-side mechanisms:

• Use JavaScript to detect inactivity and log out the user.
• Example JavaScript for redirect after inactivity:

let idleTime = 0;

const timerIncrement = () => {
    idleTime++;
    if (idleTime >= 30) { // 30 minutes
        window.location.href = "/logout"; // Redirect to logout URL
    }
};

// Reset timer on user activity
document.onmousemove = document.onkeypress = () => {
    idleTime = 0;
};

// Increment idle time every minute
setInterval(timerIncrement, 60000);

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6. Restart Tomcat

• After making changes to web.xml or server configuration, restart Tomcat for changes to take effect:

sudo systemctl restart tomcat

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7. Additional Considerations

• Session Persistence: Ensure that sessions are not serialized between restarts unless necessary.
• Single Sign-On (SSO): If using SSO, configure session timeout at the identity provider level.
• Testing: Test timeout behavior under various conditions (browser inactivity, open tabs, etc.).