List currently logged in users (wordpress)

Question

Is there a way to display a list of currently logged in users?

Ideally it would just show their name and gravatar.

Answer 1

Personaly I would use the session_tokens meta key to determine if a user is online (or has a running session) or not.

$aUsers = get_users([
    'meta_key' => 'session_tokens',
    'meta_compare' => 'EXISTS'
]);

You'll get a list of Users with running sessions. Then you can use that for your output.

echo sprintf(
    'Users online: %s',
    implode(', ', array_map(function($oUser){
        return get_avatar( $oUser->ID, 96 ) . '<span class="username">'$oUser->display_name.'</span>';
    }, $aUsers))
);

You could even display the session ip addresses if you modify the last bit of code.

echo sprintf(
    'Users online: %s',
    implode(', ', array_map(function($oUser){
        $aCurrentSessions = get_user_meta($oUser->ID, 'session_tokens', true);
        return get_avatar( $oUser->ID, 96 ) . '<span class="username">'$oUser->display_name.'</span> (' .
            implode('; ', array_map(function($aSession) {
                return $aSession['ip']; // only return the session ips
            }, $aCurrentSessions)) . ')';
    }, $aUsers))
);

Answer 2

Wordpress does not have a built in function for this, but you can easily add one yourself. For example, you can use the wp_login hook to store each users last login time. Then you can list the users that logged in within the last 30 minutes or so as online.

add_action('wp_login', 'store_last_login', 10, 2);

function store_last_login($current_user) {
    global $current_user;
    get_currentuserinfo();
    $user = $current_user->user_login;
    update_user_meta($current_user->ID, 'last_login', current_time('mysql', 1));
}

Then, you can echo out the users that logged in within the last twenty minutes ( or whatever timeframe you choose) with something like:

function list_online_users() {
$users = get_users( 'blog_id=1' );
foreach ($users as $online) {

    $getLastLogin = (get_user_meta($online->ID, 'last_login', true));
    $lastLogin = new DateTime($getLastLogin);
    $since_start = $lastLogin->diff(new DateTime(current_time('mysql', 1)));

    $minutesSinceLogin = $since_start->i;

    // this will list every user and whether they logged in within the last 30 minutes
    if ($minutesSinceLogin > 30 ) {
        echo '<li>'.$online->user_login . ' is offline </li>';
    } else { 
        echo '<li>'.$online->user_login . ' is online </li>'; 
    }

    }

}