php - 通过 PHP 脚本将文件从 FTP 服务器下载到带有 Content-Length 标头的浏览器，而不将文件存储在 Web 服务器上

Question

我使用此代码从 ftp 将文件下载到内存：

public static function getFtpFileContents($conn_id , $file)
{
    ob_start();
    $result = ftp_get($conn_id, "php://output", $file, FTP_BINARY);
    $data = ob_get_contents();
    ob_end_clean();
    if ($resul)
        return $data;
    return null;
}

如何让它直接将文件发送给用户（浏览器）而不保存到磁盘并且不重定向到 ftp 服务器？

Answer 1

只需删除输出缓冲（ob_start()和其他）。

只使用这个：

ftp_get($conn_id, "php://output", $file, FTP_BINARY);

---

虽然如果你想添加Content-Length标题，你必须首先使用查询文件大小ftp_size：

$conn_id = ftp_connect("ftp.example.com");
ftp_login($conn_id, "username", "password");
ftp_pasv($conn_id, true);

$file_path = "remote/path/file.zip";
$size = ftp_size($conn_id, $file_path);

header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=" . basename($file_path));
header("Content-Length: $size"); 

ftp_get($conn_id, "php://output", $file_path, FTP_BINARY);

（添加错误处理）

---

有关更广泛的背景，请参阅：
列出并从 FTP 下载单击的文件

Answer 2

public static function getFtpFileContentsWithSize($conn_id , $file)
{
    ob_start();
    $result = ftp_get($conn_id, "php://output", $file, FTP_BINARY);
    $data = ob_get_contents();
    $datasize = ob_get_length( );
    ob_end_clean();
    if ($result)
        return array( 'data' => $data, 'size' => $datasize );
    return null;
}


            $mapfile = SUPERFTP::getFtpFileContentsWithSize($ftpconn, $curmap['filename']);
            ftp_close($ftpconn);
            if (!$mapfile)
            {
                $viewParams['OutContext'] = "Error. File not found." ;
            }

            header('Content-Description: File Transfer');
            header('Content-Type: application/octet-stream');
            header('Content-Disposition: attachment; filename='.$curmap['filename']);
            header('Content-Transfer-Encoding: binary');
            header('Expires: 0');
            header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
            header('Pragma: public');
            header('Content-Length: ' . $mapfile['size']); 

            echo $mapfile['data'];
            exit( );

此代码有效。谢谢大家。