PHP: stream_get_meta_data

Description

array stream_get_meta_data ( resource stream )

Returns information about an existing stream. The stream can be any stream created by fopen(), fsockopen() and pfsockopen(). The result array contains the following items:

timed_out (bool) - TRUE if the stream timed out while waiting for data on the last call to fread() or fgets().
blocked (bool) - TRUE if the stream is in blocking IO mode. See stream_set_blocking().
eof (bool) - TRUE if the stream has reached end-of-file. Note that for socket streams this member can be TRUE even when unread_bytes is non-zero. To determine if there is more data to be read, use feof() instead of reading this item.
unread_bytes (int) - the number of bytes currently contained in the PHP's own internal buffer.
Замечание: You shouldn't use this value in a script.

The following items were added in PHP 4.3:

stream_type (string) - a label describing the underlying implementation of the stream.
wrapper_type (string) - a label describing the protocol wrapper implementation layered over the stream. See Прил. M for more information about wrappers.
wrapper_data (mixed) - wrapper specific data attached to this stream. See Прил. M for more information about wrappers and their wrapper data.
filters (array) - and array containing the names of any filters that have been stacked onto this stream. Documentation on filters can be found in the Filters appendix.

Замечание: This function was introduced in PHP 4.3, but prior to this version, socket_get_status() could be used to retrieve the first four items, for socket based streams only.
In PHP 4.3 and later, socket_get_status() is an alias for this function.

Замечание: This function does NOT work on sockets created by the Socket extension.

The following items were added in PHP 5.0:

mode (string) - the type of access required for this stream (see Table 1 of the fopen() reference)
seekable (bool) - whether the current stream can be seeked.
uri (string) - the URI/filename associated with this stream.

stream_get_meta_data

ed at readinged dot com
28-Jan-2003 07:54


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('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();

}