Answered Listing User Messages in Web context

[[!UserMessages]]

<?php
/* UserMessages snippet */

/* initialize variables */
$userId = $modx->user->get('id');
$output = '';

/* Get the current user's messages */
$messages = $modx->getCollection('modUserMessage', array('recipient' => $userId));

/* Loop through messages (if any) and add them to the output */
if (! empty ($messages)) {
    $output = '<h3>You have Recieved these messages</h3>';
    foreach ($messages as $message) {

        $fields = $message->toArray();
        /* replace sender ID with username */
        if (isset($fields['sender'])) {
            $sender = $modx->getObject('modUser', (integer) $fields['sender']);
            if ($sender) {
                $fields['sender'] = $sender->get('username');
            }
        }
        $output .= $modx->getChunk('messageTpl', $fields);
    }
} else {
    $output = '<h3>You have no messages</h3>';
}

return $output;

<p>Subject: [[+subject]]</p>
<p>Sender: [[+sender]]</p>
<p>Message: [[+message]]</p>

      type  (string)
      subject  (string)
      message  (string)
      sender  (integer)
      recipient  (integer)
      private  (integer)
      date_sent  (datetime)
      read  (integer)