function _filterHost($host)
    {
        if (strstr($host, ':') !== false)
            throw new \InvalidArgumentException('Host name can`t contains port number.');

        $host = strtolower($host);
        return $host;
    }
function _filterHost($host)
    {
        if (strstr($host, ':') !== false)
            throw new \InvalidArgumentException('Host name can`t contains port number.');

        $host = strtolower($host);
        return $host;
    }
function _filterHost ( $ host ) { if ( strstr ( $ host , ':' ) !== false ) throw new \ InvalidArgumentException ( 'Host name can`t contains port number.' ) ; $ host = strtolower ( $ host ) ; return $ host ; }
Validate and Filter host value
@param string $host
@return string normalized value
Validate and Filter host value