getRandomString() public static method

Do not use for security related purposes (the string is not truly random).
public static getRandomString ( integer $length = 16, string $alphabet = "abcdefghijklmnoprstuvwxyz0123456789" ) : string
$length integer string length
$alphabet string characters allowed in random string
return string random string with given length
 protected function write(array $record)
 {
     switch ($record['level']) {
         case Logger::EMERGENCY:
         case Logger::ALERT:
         case Logger::CRITICAL:
         case Logger::ERROR:
             $context = Notification::CONTEXT_ERROR;
             break;
         case Logger::WARNING:
             $context = Notification::CONTEXT_WARNING;
             break;
         default:
             $context = Notification::CONTEXT_INFO;
             break;
     }
     $message = $record['level_name'] . ': ' . htmlentities($record['message']);
     $notification = new Notification($message);
     $notification->context = $context;
     $notification->flags = 0;
     try {
         Manager::notify(Common::getRandomString(), $notification);
     } catch (Zend_Session_Exception $e) {
         // Can happen if this handler is enabled in CLI
         // Silently ignore the error.
     }
 }
<?php

// Script that creates 100 websites, then outputs a IMG that records a pageview in each website
// Used initially to test how to handle cookies for this use case (see http://dev.piwik.org/trac/ticket/409)
use Piwik\Common;
use Piwik\FrontController;
use Piwik\Piwik;
use Piwik\Plugins\SitesManager\API;
exit;
define('PIWIK_INCLUDE_PATH', '../..');
define('PIWIK_ENABLE_DISPATCH', false);
define('PIWIK_ENABLE_ERROR_HANDLER', false);
define('PIWIK_ENABLE_SESSION_START', false);
require_once PIWIK_INCLUDE_PATH . "/index.php";
require_once PIWIK_INCLUDE_PATH . "/core/API/Request.php";
require_once PIWIK_INCLUDE_PATH . "/libs/PiwikTracker/PiwikTracker.php";
FrontController::getInstance()->init();
Piwik::setUserHasSuperUserAccess();
$count = 100;
for ($i = 0; $i <= $count; $i++) {
    $id = API::getInstance()->addSite(Common::getRandomString(), 'http://piwik.org');
    $t = new PiwikTracker($id, 'http://localhost/trunk/piwik.php');
    echo $id . " <img width=100 height=10 border=1 src='" . $t->getUrlTrackPageView('title') . "'><br/>";
}