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    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|false

    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()。

    参数

    此函数没有参数。

    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。

    示例

    示例 #1 getlastmod() 示例

    <?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

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    User Contributed Notes 7 notes

    up
    10
    luca dot delpivo at gmail dot com
    12 years ago
    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.
    up
    4
    Moro
    12 years ago
    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;
    }
    ?>
    up
    0
    Ant P.
    14 years ago
    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.
    up
    -1
    rwruck
    20 years ago
    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'])
    up
    -2
    Anonymous
    20 years ago
    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);
    ?>
    up
    -8
    erik dot stetina at gmail dot com
    13 years ago
    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)
    up
    -10
    timeflys at users dot sourceforget dot net
    21 years ago
    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"];
    ?>
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