public function getTimestamp($format = self::TIMESTAMP_FORMAT_RFC1123) {
		$this->ensureInput();
		if(!isset($this->input['timestamp'])) return null;
		switch($format) {
			case static::TIMESTAMP_FORMAT_UNIX:
				return strtotime($this->input['timestamp']);
			case static::TIMESTAMP_FORMAT_RFC1123:
			default:
				return $this->input['timestamp'];
		}
	}