stream_get_meta_data

(PHP 4 >= 4.3.0, PHP 5)

stream_get_meta_data从封装协议文件指针中取得报头/元数据

说明

array stream_get_meta_data ( int $fp )

返回现有 stream 的信息。可以是任何通过 fopen()fsockopen()pfsockopen() 建立的流。返回的数组包含以下项目:

  • timed_out (bool) - 如果在上次调用 fread() 或者 fgets() 中等待数据时流超时了则为 TRUE

  • blocked (bool) - 如果流处于阻塞 IO 模式时为 TRUE。参见 stream_set_blocking()

  • eof (bool) - 如果流到达文件末尾时为 TRUE。注意对于 socket 流甚至当 unread_bytes 为非零值时也可以为 TRUE。要测定是否有更多数据可读,用 feof() 替代读取本项目的值。

  • unread_bytes (int) - 当前在 PHP 自己的内部缓冲区中的字节数。

    Note: 不要在脚本中使用此值。

以下项目是 PHP 4.3 新加的:

  • stream_type (string) - 一个描述流底层实现的标注。

  • wrapper_type (string) - 一个描述流的分层协议封装实现的标注。更多关于封装协议的信息见 支持的协议和封装协议

  • wrapper_data (mixed) - 当前流附加的封装协议数据。更多封装协议及其数据的信息见 支持的协议和封装协议

  • filters (array) - 包含有被叠加在当前流的任何过滤器名的数组。过滤器的文档见附录中的可用过滤器列表

Note:

本函数是 PHP 4.3 引进的,在此版本之前,可以用 socket_get_status() 来取得前四个项目并且仅能用于基于 socket 的流

在 PHP 4.3 及以后版本中,socket_get_status() 是本函数的别名。

Note: 本函数不能作用于通过 Socket 扩展库创建的流。

以下项目为 PHP 5.0 新加:

  • mode (string) - 对当前流所要求的访问类型(见 fopen() 中的表格 1)。

  • seekable (bool) - 是否可以在当前流中定位。

  • uri (string) - 与当前流关联的 URI 或文件名。

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User Contributed Notes 4 notes

up
1
ed at readinged dot com
11 years ago
Below is a function I wrote to pull the "Last-Modified" header from a given URL.  In PHP version 4.3 and above, it takes advantage of the stream_get_meta_data function, and in older version it uses a conventional GET procedure.  On failure to connect to $url, it returns NULL.  If the server does not return the Last-Modified header, it returns the current time.  All times are returned in PHP's integer format (seconds since epoch).

Use it as so:

$last_modified = stream_last_modified('http://www.php.net/news.rss');
if (!is_null($last_modified))
   if ($last_modified < time()-3600) //Older than an hour
      echo 'URL is older than an hour.';
   else
      echo 'URL is fairly new.';
else
   echo 'Invalid URL!';

function stream_last_modified($url)
{
   if (function_exists('version_compare') && version_compare(phpversion(), '4.3.0') > 0)
   {
      if (!($fp = @fopen($url, 'r')))
         return NULL;

      $meta = stream_get_meta_data($fp);
      for ($j = 0; isset($meta['wrapper_data'][$j]); $j++)
      {
         if (strstr(strtolower($meta['wrapper_data'][$j]), 'last-modified'))
         {
            $modtime = substr($meta['wrapper_data'][$j], 15);
            break;
         }
      }
      fclose($fp);
   }
   else
   {
      $parts = parse_url($url);
      $host  = $parts['host'];
      $path  = $parts['path'];

      if (!($fp = @fsockopen($host, 80)))
         return NULL;

      $req = "HEAD $path HTTP/1.0\r\nUser-Agent: PHP/".phpversion()."\r\nHost: $host:80\r\nAccept: */*\r\n\r\n";
      fputs($fp, $req);

      while (!feof($fp))
      {
         $str = fgets($fp, 4096);
         if (strstr(strtolower($str), 'last-modified'))
         {
            $modtime = substr($str, 15);
            break;
         }
      }
      fclose($fp);
  }
   return isset($modtime) ? strtotime($modtime) : time();
}
up
1
php dot chaska at xoxy dot net
6 months ago
In PHP 5.4.24 and 5.4.25, this command does not correctly return the stream blocking status.  It always returns ['blocked'] == 1 regardless of the actual blocking mode.  A call to stream_set_blocking($stream, 0) will succeed (return TRUE) and subsequent calls to stream_get_contents($stream) will NOT block, even though a call to stream_get_meta_data($stream) will return 'blocked' == 1.  Hopefully this will save some people a bunch of debugging time.

See bug report #47918 for more information (http://bugs.php.net/bug.php?id=47918).

Proof:
<?php
$d
= array(
   
0 => array('pipe', 'r'),
   
1 => array('pipe', 'w'),
   
2 => array('file', 'error.log', 'a')
);

$p = proc_open('php -S localhost:8000', $d, $pipes);

if (!
is_resource($p))   die("proc_open() failed\n");

// Set child's stdout pipe to non-blocking.
if (!stream_set_blocking($pipes[1], 0)) {
    die(
"stream_set_blocking() failed\n");
}
else {
    echo
"Non-blocking mode should be set.\n";
}

// View the status of that same pipe.
// Note that 'blocked' is 1!  This appears to be wrong.
print_r(stream_get_meta_data($pipes[1]));

// Try to read something.  This will block if in blocking mode.
// If it does not block, stream_set_blocking() worked but
// stream_get_meta_data() is lying about blocking mode.
$data = stream_get_contents($pipes[1]);

echo
"data = '$data'\n";
?>

Output:
Non-blocking mode should be set.
Array
(
    [stream_type] => STDIO
    [mode] => r
    [unread_bytes] => 0
    [seekable] =>
    [timed_out] =>
    [blocked] => 1         // << claims to be in blocking mode
    [eof] =>
)
data = ''                      // this would never appear if we blocked.
up
0
derkontrollfreak+9hy5l at gmail dot com
3 months ago
Apparently, custom wrappers are always seekable.
up
-1
niels at nise81 dot com
6 years ago
here is just an example how to read out all meta data.
how ever I found out that the "seekable"-entry doesn't exist in most of the streaming media files.

      if (!($fp = @fopen($url, 'r')))
         return NULL;

      $meta = stream_get_meta_data($fp);
     
          foreach(array_keys($meta) as $h){
              $v = $meta[$h];
              echo "".$h.": ".$v."<br/>";
              if(is_array($v)){
                  foreach(array_keys($v) as $hh){
                      $vv = $v[$hh];
                      echo "_".$hh.": ".$vv."<br/>";
                  }
              }
          }
      fclose($fp);
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