Php 直接下载远程文件到客户端？

我需要下载远程文件直接到客户端。在谷歌搜索之后，我在php手册中找到了这个脚本，但是它的恢复功能不起作用。此脚本使用Http_范围生成可恢复的下载链接。还有其他方法吗？当然，这将是通过使用cUrl实现的，但我需要直接将远程文件下载到客户端。我如何解决这个问题

<?php          
$url="http://dl.remote-domain.com/files/file.mp4";
dl_file_resumable($url);

function dl_file_resumable($file, $is_resume=TRUE)
{


    //Gather relevent info about file
    $size = remotefilesize($file);
    $fileinfo = pathinfo($file);

    //workaround for IE filename bug with multiple periods / multiple dots in filename
    //that adds square brackets to filename - eg. setup.abc.exe becomes setup[1].abc.exe
    $filename = (strstr($_SERVER['HTTP_USER_AGENT'], 'MSIE')) ?
                  preg_replace('/\./', '%2e', $fileinfo['basename'], substr_count($fileinfo

['basename'], '.') - 1) :
                  $fileinfo['basename'];

    $file_extension = strtolower($path_info['extension']);

    //This will set the Content-Type to the appropriate setting for the file
    switch($file_extension)
    {
        case 'exe': $ctype='application/octet-stream'; break;
        case 'zip': $ctype='application/zip'; break;
        case 'mp3': $ctype='audio/mpeg'; break;
        case 'mpg': $ctype='video/mpeg'; break;
        case 'avi': $ctype='video/x-msvideo'; break;
        default:    $ctype='application/force-download';
    }

    //check if http_range is sent by browser (or download manager)
    if($is_resume && isset($_SERVER['HTTP_RANGE']))
    {
        list($size_unit, $range_orig) = explode('=', $_SERVER['HTTP_RANGE'], 2);

        if ($size_unit == 'bytes')
        {
            //multiple ranges could be specified at the same time, but for simplicity only 

serve the first range
            //http://tools.ietf.org/id/draft-ietf-http-range-retrieval-00.txt
            list($range, $extra_ranges) = explode(',', $range_orig, 2);
        }
        else
        {
            $range = '';
        }
    }
    else
    {
        $range = '';
    }

    //figure out download piece from range (if set)
    list($seek_start, $seek_end) = explode('-', $range, 2);

    //set start and end based on range (if set), else set defaults
    //also check for invalid ranges.
    $seek_end = (empty($seek_end)) ? ($size - 1) : min(abs(intval($seek_end)),($size - 1));
    $seek_start = (empty($seek_start) || $seek_end < abs(intval($seek_start))) ? 0 : max(abs

(intval($seek_start)),0);

    //add headers if resumable
    if ($is_resume)
    {
        //Only send partial content header if downloading a piece of the file (IE workaround)
        if ($seek_start > 0 || $seek_end < ($size - 1))
        {
            header('HTTP/1.1 206 Partial Content');
        }

        header('Accept-Ranges: bytes');
        header('Content-Range: bytes '.$seek_start.'-'.$seek_end.'/'.$size);
    }

    //headers for IE Bugs (is this necessary?)
    //header("Cache-Control: cache, must-revalidate");   
    //header("Pragma: public");

    header('Content-Type: ' . $ctype);
    header('Content-Disposition: attachment; filename="' . $filename . '"');
    header('Content-Length: '.($seek_end - $seek_start + 1));

    //open the file
    $fp = fopen($file, 'rb');
    //seek to start of missing part
    fseek($fp, $seek_start);

    //start buffered download
    while(!feof($fp))
    {
        //reset time limit for big files
        set_time_limit(0);
        print(fread($fp, 1024*8));
        flush();
        ob_flush();
    }

    fclose($fp);
    exit;
}

function remotefilesize($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 isset($matches[1]) ? $matches[1] : "unknown";
}
?>

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如果只想将文件推送到用户，请执行以下步骤：

启动输出缓冲。 按原样读取要缓冲的文件内容。 将响应头设置为基于mime类型，如您发布的代码中所示。 刷新输出缓冲区。

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如果mime类型不能按照浏览器标准呈现，系统将提示用户保存文件。

我知道你的意思，在上面的代码中尝试这样做。你有什么样的代码吗？谢谢。当前脚本的确切问题是什么？