How can I ping a server port with PHP?

ping.php

<?php

function ping($ip, $port = 80, $timeout = 1) {
  try {
    $output = [];
    $result = null;

    exec("ping -c 4 " . escapeshellarg($ip), $output, $result);

    if ($result === 0) {
      foreach ($output as $line) {
        if (preg_match('/time=(\d+\.\d+) ms/', $line, $matches)) {
          return floatval($matches[1]) . 'ms';
        }
      }
    }
  } catch (\Throwable $th) {
    $start = microtime(true);
    $fp = @fsockopen($ip, $port, $errno, $errstr, $timeout);

    if ($fp) {
      fclose($fp);
      $end = microtime(true);
      $duration = ($end - $start) * 1000; // to millisecond
      return round($duration, 2) . 'ms';
    }
  }
  
  return 'Unavailable';
}