Log Out Idle Users Automatically

// Minutes of inactivity before logout.
$wpide_idle_minutes = 30;

$wpide_idle_script = function () use ( $wpide_idle_minutes ) {
    if ( ! is_user_logged_in() ) {
        return;
    }

    $logout = wp_logout_url( add_query_arg( 'wpide_idle', '1', wp_login_url() ) );
    ?>
    <script>
    ( function () {
        var limit = <?php echo (int) $wpide_idle_minutes; ?> * 60000, key = 'wpideLastActivity', local = Date.now();
        function touch() {
            local = Date.now();
            try { localStorage.setItem( key, String( local ) ); } catch ( e ) {}
        }
        function last() {
            var shared = 0;
            try { shared = parseInt( localStorage.getItem( key ), 10 ) || 0; } catch ( e ) {}
            return Math.max( shared, local );
        }
        [ 'mousemove', 'keydown', 'scroll', 'click', 'touchstart' ].forEach( function ( evt ) {
            window.addEventListener( evt, function () { if ( Date.now() - local > 15000 ) { touch(); } }, { passive: true } );
        } );
        touch();
        setInterval( function () {
            if ( Date.now() - last() > limit ) {
                window.location.href = <?php echo wp_json_encode( $logout ); ?>;
            }
        }, 30000 );
    } )();
    </script>
    <?php
};

add_action( 'admin_footer', $wpide_idle_script );
add_action( 'wp_footer', $wpide_idle_script );

add_filter( 'login_message', function ( $message ) use ( $wpide_idle_minutes ) {
    if ( isset( $_GET['wpide_idle'] ) ) {
        $message .= '<p class="message">' . esc_html( sprintf( 'You were logged out after %d minutes of inactivity.', $wpide_idle_minutes ) ) . '</p>';
    }

    return $message;
} );