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PHP : Function Reference : Stream Functions : stream_get_meta_data

stream_get_meta_data

Retrieves header/meta data from streams/file pointers (PHP 4 >= 4.3.0, PHP 5)
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.

    Note:

    You shouldn't use this value in a script.

The following items were added in PHP 4.3.0:

  • 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 Appendix O, List of Supported Protocols/Wrappers for more information about wrappers.

  • wrapper_data (mixed) - wrapper specific data attached to this stream. See Appendix O, List of Supported Protocols/Wrappers 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.

Note:

This function was introduced in PHP 4.3.0, but prior to this version, socket_get_status() could be used to retrieve the first four items, for socket based streams only.

In PHP 4.3.0 and later, socket_get_status() is an alias for this function.

Note:

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

The following items were added in PHP 5.0.0:

  • 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.

Code Examples / Notes » stream_get_meta_data

ed

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();
}


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stream_bucket_append
stream_bucket_make_writeable
stream_bucket_new
stream_bucket_prepend
stream_context_create
stream_context_get_default
stream_context_get_options
stream_context_set_option
stream_context_set_params
stream_copy_to_stream
stream_encoding
stream_filter_append
stream_filter_prepend
stream_filter_register
stream_filter_remove
stream_get_contents
stream_get_filters
stream_get_line
stream_get_meta_data
stream_get_transports
stream_get_wrappers
stream_register_wrapper
stream_resolve_include_path
stream_select
stream_set_blocking
stream_set_timeout
stream_set_write_buffer
stream_socket_accept
stream_socket_client
stream_socket_enable_crypto
stream_socket_get_name
stream_socket_pair
stream_socket_recvfrom
stream_socket_sendto
stream_socket_server
stream_socket_shutdown
stream_wrapper_register
stream_wrapper_restore
stream_wrapper_unregister
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