$patterns = [
    'mailid' => '/postfix\/smtp\[\w+\]:\s(\w+)/',
    'mailto' => '/to=<(.*?)>/',
    'datetime' => '/(\w+\s+\w+\s+\w+:\w+:\w+)/',
    'host' => '/.*?\(host\s(.*?)\[.*/',
    'hostip' => '/.*?\(host\s.*?\[(.*?)\]\s.*/',
	'reason' => '/status=\w+\s(.*)/',
];

$data = [];
foreach ($patterns as $key => $pattern) {
    preg_match_all($pattern, $output, $matches);
    $data[$key] = $matches[1];
}

header('Content-Type: application/json');
echo json_encode($data);
?>