text: <?php
  /*
   +--------------------------------------------------------------------+
   | Copyright CiviCRM LLC. All rights reserved.                        |
   |                                                                    |
   | This work is published under the GNU AGPLv3 license with some      |
   | permitted exceptions and without any warranty. For full license    |
   | and copyright information, see https://civicrm.org/licensing       |
   +--------------------------------------------------------------------+
   */
  
  /**
   * @package CRM
   * @copyright CiviCRM LLC https://civicrm.org/licensing
   */
  
  /**
   * Simple static helpers for network operations
   */
  class CRM_Utils_Network {
  
    /**
     * Try connecting to a TCP service; if it fails, retry. Repeat until serverStartupTimeOut elapses.
     *
     * @param $host
     * @param $port
     * @param int $serverStartupTimeOut
     *   Seconds.
     * @param float $interval
     *   Seconds to wait in between pollings.
     *
     * @return bool
     *   TRUE if service is online
     */
    public static function waitForServiceStartup($host, $port, $serverStartupTimeOut, $interval = 0.333) {
      $start = time();
      $end = $start + $serverStartupTimeOut;
      $found = FALSE;
      $interval_usec = (int) 1000000 * $interval;
  
      while (!$found && $end >= time()) {
        $found = self::checkService($host, $port, $end - time());
        if ($found) {
          return TRUE;
        }
        usleep($interval_usec);
      }
      return FALSE;
    }
  
    /**
     * Check whether a TCP service is available on $host and $port.
     *
     * @param string $host
     * @param string $port
     * @param string $serverConnectionTimeOut
     *
     * @return bool
     */
    public static function checkService($host, $port, $serverConnectionTimeOut) {
      $old_error_reporting = error_reporting();
      error_reporting($old_error_reporting & ~E_WARNING);
      try {
        $fh = fsockopen($host, $port, $errno, $errstr, $serverConnectionTimeOut);
        if ($fh) {
          fclose($fh);
          error_reporting($old_error_reporting);
          return TRUE;
        }
      }
      catch (Exception $e) {
      }
      error_reporting($old_error_reporting);
      return FALSE;
    }
  
  }
  