header 头各种类型文件下载

function down_file($url,$type='application/zip'){
    header("Cache-Control: public"); 
    header("Content-Description: File Transfer"); 
    header('Content-disposition: attachment; filename='.basename($url)); //文件名   
    header("Content-Type: ".$type); //zip格式的   
    header("Content-Transfer-Encoding: binary"); //告诉浏览器，这是二进制文件    
    header('Content-Length: '. filesize($url)); //告诉浏览器，文件大小   
    @readfile($url);
}

   //下载外部链接到客户端本地
    public function download($url)
    {$type = $this->getFileType($url);
        $size = $this -> getFileSize($url);
        header("Cache-Control: public");
        header("Content-Description: File Transfer");
        header('Content-disposition: attachment; filename='.basename($url)); //文件名
        header("Content-Type: ".$type); //zip格式的
//        header("Content-Transfer-Encoding: binary"); //告诉浏览器，这是二进制文件
        header('Content-Length: '. $size); //告诉浏览器，文件大小
        @readfile($url);
    }


   //获取外部链接文件大小
    function getFileSize($url, $user = "", $pw = "")
    {
        ob_start();
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_HEADER, 1);
        curl_setopt($ch, CURLOPT_NOBODY, 1);

        if(!empty($user) && !empty($pw))
        {
            $headers = array('Authorization: Basic ' .  base64_encode("$user:$pw"));
            curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        }

        $ok = curl_exec($ch);
        curl_close($ch);
        $head = ob_get_contents();
        ob_end_clean();

        $regex = '/Content-Length:\s([0-9].+?)\s/';
        $count = preg_match($regex, $head, $matches);

        return $matches[1];
    }



    //获取外部链接文件类型
    function getFileType($url)
    {
        $file_type=explode('.',$url);

        $file_type=$file_type[count($file_type)-1];

        return $file_type;
    }