$re = '/rid\=(?<rid>[^ ]+)\s+service\=(?<service>[^ ]+)\s+scopes\=(?<scopes>[^ ]+)\s+fields\=(?<fields>[^ ]+)\s+issuer\=(?<issuer>.+)\s+empty\=(?<empty>.*)/m';
$str = 'rid=iqwenoasd service=CP scopes=add-w,oot-s fields=birthdate,emails,identifier issuer=AWS CA TE empty=';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php