i want to know the time of last modification on a file on the web
let's pretend is a website
on this server file.xml is modified every 45 minutes. I want to find the exactly time of the last modification. There is one more problem. Acces on this file si with a username and password.
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You could try accessing through

I think, however, that you will not be allowed to get the filemtime on remote files thru http.

fradolcinoAuthor Commented:
the problem is that the validation form is not a php form, is windows specific
Which validation form?

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You may, though not always works, check the "Last-Modified:" field of the response header when you send a HTTP request to the target page.


function filemtime_http ($url) {
  $a = parse_url ($url);
  if ($a['scheme'] == 'http') {
    $fp = fsockopen($a['host'], 80, $errno, $errstr, 30);
    if (!$fp)
      trigger_error("HTTP Error #$errno: $errstr.", E_USER_ERROR);
    else {
      fwrite ($fp, "HEAD $a[path] HTTP/1.1\r\nHost: $a[host]\r\nConnection: Close\r\n\r\n");
      $ss = substr(fgets($fp),0,-2);
      while (!feof($fp)) {
        $s = fgets($fp);
        if ( preg_match ('|^Last-Modified: (.+)$|', $s, $a) ) {
          return $a[1];
      trigger_error("Cannot get last modified date. Server returned: $ss. Current date is returned instead.");
      fclose ($fp);
      return date('r');
  } else
    trigger_error("Not a valid URL.", E_USER_ERROR);

echo filemtime_http ('') . '<br />'; #Should return Fri, 29 Sep 2000 20:48:57 GMT
echo filemtime_http ('') . '<br />'; #Should issue a notice and return the time now.

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BTW, apply a strtotime() on the returned value to get the UNIX timestamp.
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