php - PHP 从特定服务器获取时间

Question

只是想知道 PHP 中是否有一种方法可以从特定服务器（例如谷歌）检索时间。我想制作一个可以检索服务器上设置的时间的脚本。

谢谢 ：）

Answer 1

如果您可以信任 HTTP 请求返回的Date:标头，您可以在PHP中使用cURL执行类似的操作。

<?                                                                                                                                  
$date = null;

function header_callback($curl, $header)
{
    global $date;

    if (preg_match('/^Date:/', $header)) {
        $date = trim(substr($header, 5));
        $date = DateTime::createFromFormat('D, d M Y H:i:s e', $date);
    }

    return strlen($header);
}

$curl = curl_init("http://www.google.com/");

curl_setopt($curl, CURLOPT_NOBODY, true);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HEADERFUNCTION, 'header_callback');

curl_exec($curl);

curl_close($curl);

if ($date != NULL) {
    echo "Date from HTTP: " . $date->format('r');
}
?>

Answer 2

没有内置的 PHP 函数来查询特定的时间服务器，但您可以编写一个脚本来执行此操作。可以在此页面上找到一些示例：http ://www.kloth.net/software/timesrv1.php

上一个链接中的这个示例在端口 37 上使用了 TIME 协议：

<?php
/* Query a time server
   (C) 1999-09-29, Ralf D. Kloth (QRQ.software) <ralf at qrq.de> 
*/

function query_time_server ($timeserver, $socket) {    
  $fp = fsockopen($timeserver,$socket,$err,$errstr,5);
        # parameters: server, socket, error code, error text, timeout
  if ($fp) {
    fputs($fp,"\n");
    $timevalue = fread($fp,49);
    fclose($fp); # close the connection
  }
  else {
    $timevalue = " ";
  }

  $ret = array();
  $ret[] = $timevalue;
  $ret[] = $err;     # error code
  $ret[] = $errstr;  # error text
  return($ret);

} # function query_time_server 

$timeserver = "ntp1.sf-bay.org";
$timercvd = query_time_server($timeserver,37);
if (!$timercvd[1]) { # if no error from query_time_server
  $timevalue = bin2hex ($timercvd[0]);
  $timevalue = abs (HexDec('7fffffff') - HexDec($timevalue) - HexDec('7fffffff')) ;
  $tmestamp = $timevalue - 2208988800; # convert to UNIX epoch time stamp
  $datum = date("Y-m-d (D) H:i:s",$tmestamp - date("Z",$tmestamp)); /* incl time zone offset */
  $doy = (date("z",$tmestamp)+1);

  echo "Time check from time server ",$timeserver," : [<font color=\"red\">",$timevalue,"</font>]";
  echo " (seconds since 1900-01-01 00:00.00).<br>\n";
  echo "The current date and universal time is ",$datum," UTC. ";
  echo "It is day ",$doy," of this year.<br>\n";
  echo "The unix epoch time stamp is $tmestamp.<br>\n";
} #if (!$timercvd)
else {
  echo "Unfortunately, the time server $timeserver could not be reached at this time. ";
  echo "$timercvd[1] $timercvd[2].<br>\n";
} # else
?>