silverstripe-multiform/code/MultiFormPurgeTask.php

<?php

/**
 * Task to clean out all {@link MultiFormSession} objects from the database.
 * 
 * Setup Instructions:
 * You need to create an automated task for your system (cronjobs on unix)
 * which triggers the run() method through cli-script.php:
 * /your/path/sapphire/cli-script.php MultiFormPurgeTask/run
 * 
 * @package multiform
 */
class MultiFormPurgeTask extends DailyTask {
	
	/**
	 * Days after which sessions expire and
	 * are automatically deleted.
	 * 
	 * @usedby {@link MultiFormPurgeTask}
	 * @var int
	 */
	public static $session_expiry_days = 7;

	/**
	 * Run this cron task.
	 * 
	 * Go through all MultiFormSession records that
	 * are older than the days specified in $session_expiry_days
	 * and delete them.
	 */
	public function run() {
		$sessions = $this->getExpiredSessions();
		if($sessions) foreach($sessions as $session) {
			$session->delete();
		}
	}

	/**
	 * Return all MultiFormSession database records that are older than
	 * the days specified in $session_expiry_days
	 *
	 * @return DataObjectSet
	 */
	protected function getExpiredSessions() {
		return DataObject::get(
			'MultiFormSession',
			"DATEDIFF(NOW(), `MultiFormSession`.`Created`) > " . self::$session_expiry_days);
	}
	
}

?>