做了下title转码、对于文件链接只取前1k（服务器支持断点下载的情况下

get_title_via_url.php

<?php
function get_title_via_url( $url )
{
	// 抓取前1024个字节
	$context=array('http' => array ('header'=> 'Range: bytes=0-1024' ));
	$xcontext = stream_context_create($context);
	$content = strtolower( file_get_contents( $url , FALSE,$xcontext ) );

	$reg = '/<title>(.+?)<\/title>/is';

	if( preg_match( $reg , $content , $out ) )
	{
		$title = $out[1];
        	if(!is_utf8( $content )) $title = mb_convert_encoding( $title , 'UTF-8' , 'GBK' );
    		return $title;
	}

	return basename( $url );
}

function is_utf8( $content )
{
  $content = strtolower($content);
  $reg = '/<meta.+?charset=[\'"]?([a-z0-9\-]+)[\'"]/is';
  if(preg_match( $reg , $content , $out ))
  {
  	return 	$out[1] == 'utf-8';
  } 
}
?>