getlastmod

(PHP 4, PHP 5, PHP 7, PHP 8)

getlastmod获取页面最后修改的时间

说明

getlastmod ( ) : int

获取执行的主脚本的最后修改时间。

如果你对其他文件的最后修改时间的感兴趣,可考虑使用 filemtime()

返回值

返回当前页面最后修改的时间。这个值是一个 Unix 时间戳,可以传入 date()。 错误时返回 false

范例

Example #1 getlastmod() 例子

<?php
// 输出类似 'Last modified: March 04 1998 20:43:59.'
echo "Last modified: " date ("F d Y H:i:s."getlastmod());
?>

参见

User Contributed Notes

Moro 29-Jun-2012 03:03
Return latest mod time of all included files:

<?php
function get_page_mod_time() {
   
$incls = get_included_files();
   
$incls = array_filter($incls, "is_file");
   
$mod_times = array_map('filemtime', $incls);
   
$mod_time = max($mod_times);

    return
$mod_time;
}
?>
luca dot delpivo at gmail dot com 11-Mar-2012 07:52
With better words getlastmod() returning the last time the script in which it is being called was modified, it does not require or use a parameter.
erik dot stetina at gmail dot com 27-Sep-2011 03:47
function for displaying last modification time accross more direcotries. e.g. to display last modification date in "about" section of your web page

<?php
function array_prefix_values($prefix, $array)
{
 
$callback = create_function('$s','return "'.$prefix.'".$s;');
  return
array_map($callback,$array);
}

function
get_last_update()
{
  if (
func_num_args() < 1 ) return 0;
 
$dirs = func_get_args();
 
$files = array();
  foreach (
$dirs as $dir )
  {
   
$subfiles = scandir($dir);
   
$subfiles = array_prefix_values($dir,$subfiles);
   
$subfiles = array_filter($subfiles,"is_file");
   
$files = array_merge($files,$subfiles);
  }
 
$maxtimestamp = 0;
 
$maxfilename = "";
  foreach (
$files as $file )
  {
   
$timestamp = filemtime($file);
    if (
$timestamp > $maxtimestamp )
    {
     
$maxtimestamp = $timestamp;
     
$maxfilename = $file;
    }
  }
  return
date("Ymd",$maxtimestamp)." ($maxfilename)";
}

print
"last update: ".get_last_update("./lib/", "./css/", "./lang/");
?>

OUTPUT:
last update: 20110927 (./lang/sk.php)
Ant P. 24-Feb-2010 10:48
If you use register_shutdown_function() on certain SAPIs, various filesystem-related things inside the shutdown function might do unexpected things, one of which being this function can return false.

On the other hand getlastmod() apparently caches the return value, so if you use it at least once in normal code it should work for the remainder of the request.
rwruck 17-Oct-2004 06:28
DO NOT use this function unless you are absolutely sure both your Apache and PHP have been compiled with the same value for -DFILE_OFFSET_BITS.

If not, this function will return the access time (or maybe even garbage) instead of the modification time due do Apache and PHP using different versions of the stat structure.

This is true regardless of Apache and PHP version.

To be on the safe side, always use the workaround already posted below:
filemtime($_SERVER['SCRIPT_FILENAME'])
19-May-2004 04:36
Setting the 'Last-Modified' header:
<?php
setlocale
(LC_TIME, "C");
$ft = filemtime ('referencefile');
$localt = mktime ();
$gmtt = gmmktime ();
$ft = $ft - $gmtt + $localt;
$modified = strftime ("%a, %d %b %Y %T GMT", $ft);
?>
timeflys at users dot sourceforget dot net 20-Mar-2003 01:28
I found issues using getlastmod() to test whether or not I was successful in setting the Last Modified date in the header. The code below shows the same Last Modified date before and after I set the Last-Modified header.

<?php
//True modified date
$modified = date ("F d Y H:i:s.", getlastmod());
   
//artificial modified date - sent to header
$last_modified = gmdate('D, d M Y H:i:s T', (time() - 43200));
    
//caching prevention
header("Last-Modified: $last_modified GMT");
header("Cache-Control: no-store, no-cache, must-revalidate");  // HTTP/1.1
header("Cache-Control: post-check=0, pre-check=0", false);
   
header("Pragma: no-cache");                          // HTTP/1.0

$getlast_modified = date ("F d Y H:i:s.", getlastmod());

print
"True modified date(Before): $modified <p /> Date sent to header(After): $getlast_modified";
?>

I then used the PEAR, HTTP_Request class which worked, the Last-Modified date updates everytime it is requested, the desired effect.

<?php
require 'HTTP/Request.php';
$r = new HTTP_Request('http://www.sample.com/page.php');
$r->sendRequest();
$response_headers = $r->getResponseHeader();
print
$response_headers["last-modified"];
?>