MODX UserIsLoggedin - Checks whether or not a user is logged in and does something with it

userisloggedin.snippet.php

<?php
/**
 * UserIsLoggedin
 * Checks whether or not a user is logged in or not and does something with it
 *
 * Examples (top-down):
 *  [[!UserIsLoggedin? &redirectToOnNotAuthorized=`id-of-page`]]
 *      OR
 *  [[!UserIsLoggedin? &sendUnauthorized=`1`]]
 *      OR
 *  [[!UserIsLoggedin? &memberOf=`Usergroup1,Usergroup2` &outputTrue=`<p>You're allowed to see this!</p>`]]
 *      OR
 *  [[!UserIsLoggedin? &outputTrue=`<p>You're logged in!</p>` &outputFalse=`<p>You're not logged in!</p>`]]
 *  [[!UserIsLoggedin? &userAgainst=`id-of-user` &outputTrue=`<p>You may see this!</p>` &outputFalse=`<p>You may not see this!</p>`]]
 *  [[!UserIsLoggedin? &userNotAgainst=`id-of-user` &outputTrue=`<p>You're not yourself, you may see this</p>` &outputFalse=`...`]]
 */

// properties
$redirectToOnNotAuthorized = (integer) $modx->getOption('redirectToOnNotAuthorized', $scriptProperties, 0);
$sendUnauthorized = (boolean) $modx->getOption('sendUnauthorized', $scriptProperties, 0);

$memberOf = $modx->getOption('memberOf', $scriptProperties, '');
if(!empty($memberOf)) { $memberOf = explode(',', $memberOf); }

$userAgainst = $modx->getOption('userAgainst', $scriptProperties, 0);
if(!empty($userAgainst)) { $userAgainst = explode(',', $userAgainst); }
$userNotAgainst = $modx->getOption('userNotAgainst', $scriptProperties, 0);
if(!empty($userNotAgainst)) { $userNotAgainst = explode(',', $userNotAgainst); }

$outputTrue = $modx->getOption('outputTrue', $scriptProperties, '');
$outputFalse = $modx->getOption('outputFalse', $scriptProperties, '');

$user =& $modx->user;
if(!$user->hasSessionContext($modx->context->get('key'))) {
    if(!empty($redirectToOnNotAuthorized) && is_numeric($redirectToOnNotAuthorized)) {
        $url = $modx->makeUrl($redirectToOnNotAuthorized, '', 'full');
        $modx->sendRedirect($url);
    } else if(!empty($sendUnauthorized) && $sendUnauthorized === true) {
        $modx->sendUnauthorizedPage();
    }
    
    return $outputFalse;
}

$userId = $user->get('id');
if(
    (!empty($userAgainst) && is_array($userAgainst) && !in_array($userId, $userAgainst)) || 
    (!empty($userNotAgainst) && is_array($userNotAgainst) && in_array($userId, $userNotAgainst)) || 
    (!empty($memberOf) && !$user->isMember($memberOf))
) {
    
    return $outputFalse;
}

return $outputTrue;