使用PHP发送文件时可以断点续传吗？

Question

我们使用 PHP 脚本进行隧道文件下载，因为我们不想公开可下载文件的绝对路径：

header("Content-Type: $ctype");
header("Content-Length: " . filesize($file));
header("Content-Disposition: attachment; filename=\"$fileName\"");
readfile($file);

不幸的是，我们注意到最终用户无法恢复通过此脚本传递的下载。

有什么办法可以使用这种基于 PHP 的解决方案来支持断点续传下载吗？

Answer 1

您需要做的第一件事是在所有响应中发送 Accept-Ranges: bytes 标头，以告诉客户端您支持部分内容。然后，如果收到带有 Range: bytes=xy 标头的请求（x 和 y 是数字），您将解析范围客户端发出请求，照常打开文件，向前查找 x 字节并发送接下来的 y - x 字节。还将响应设置为 HTTP/1.0 206 Partial Content。

在没有测试过任何东西的情况下，这或多或少是可行的：

$filesize = filesize($file);

$offset = 0;
$length = $filesize;

if ( isset($_SERVER['HTTP_RANGE']) ) {
    // if the HTTP_RANGE header is set we're dealing with partial content

    $partialContent = true;

    // find the requested range
    // this might be too simplistic, apparently the client can request
    // multiple ranges, which can become pretty complex, so ignore it for now
    preg_match('/bytes=(\d+)-(\d+)?/', $_SERVER['HTTP_RANGE'], $matches);

    $offset = intval($matches[1]);
    $length = intval($matches[2]) - $offset;
} else {
    $partialContent = false;
}

$file = fopen($file, 'r');

// seek to the requested offset, this is 0 if it's not a partial content request
fseek($file, $offset);

$data = fread($file, $length);

fclose($file);

if ( $partialContent ) {
    // output the right headers for partial content

    header('HTTP/1.1 206 Partial Content');

    header('Content-Range: bytes ' . $offset . '-' . ($offset + $length) . '/' . $filesize);
}

// output the regular HTTP headers
header('Content-Type: ' . $ctype);
header('Content-Length: ' . $filesize);
header('Content-Disposition: attachment; filename="' . $fileName . '"');
header('Accept-Ranges: bytes');

// don't forget to send the data too
print($data);

我可能错过了一些明显的东西，而且我肯定忽略了一些潜在的错误来源，但这应该是一个开始。

这里有一个部分内容的描述，我在 fread 的文档页面上找到了一些有关部分内容的信息。

Answer 2

编辑 2017/01 - 我用 PHP >=7.0 编写了一个库来执行此操作 https: //github.com/DaveRandom/Resume

编辑 2016/02 - 代码完全重写为一组模块化工具和示例用法，而不是单一的 功能。下面评论中提到的更正已被纳入。

---

一个经过测试的、有效的解决方案（很大程度上基于上面 Theo 的答案），它在一组几个独立工具中处理可恢复下载。此代码需要 PHP 5.4 或更高版本。

该解决方案仍然只能处理每个请求的一个范围，但在我能想到的标准浏览器的任何情况下，这都不会引起问题。

<?php

/**
 * Get the value of a header in the current request context
 *
 * @param string $name Name of the header
 * @return string|null Returns null when the header was not sent or cannot be retrieved
 */
function get_request_header($name)
{
    $name = strtoupper($name);

    // IIS/Some Apache versions and configurations
    if (isset($_SERVER['HTTP_' . $name])) {
        return trim($_SERVER['HTTP_' . $name]);
    }

    // Various other SAPIs
    foreach (apache_request_headers() as $header_name => $value) {
        if (strtoupper($header_name) === $name) {
            return trim($value);
        }
    }

    return null;
}

class NonExistentFileException extends \RuntimeException {}
class UnreadableFileException extends \RuntimeException {}
class UnsatisfiableRangeException extends \RuntimeException {}
class InvalidRangeHeaderException extends \RuntimeException {}

class RangeHeader
{
    /**
     * The first byte in the file to send (0-indexed), a null value indicates the last
     * $end bytes
     *
     * @var int|null
     */
    private $firstByte;

    /**
     * The last byte in the file to send (0-indexed), a null value indicates $start to
     * EOF
     *
     * @var int|null
     */
    private $lastByte;

    /**
     * Create a new instance from a Range header string
     *
     * @param string $header
     * @return RangeHeader
     */
    public static function createFromHeaderString($header)
    {
        if ($header === null) {
            return null;
        }

        if (!preg_match('/^\s*(\S+)\s*(\d*)\s*-\s*(\d*)\s*(?:,|$)/', $header, $info)) {
            throw new InvalidRangeHeaderException('Invalid header format');
        } else if (strtolower($info[1]) !== 'bytes') {
            throw new InvalidRangeHeaderException('Unknown range unit: ' . $info[1]);
        }

        return new self(
            $info[2] === '' ? null : $info[2],
            $info[3] === '' ? null : $info[3]
        );
    }

    /**
     * @param int|null $firstByte
     * @param int|null $lastByte
     * @throws InvalidRangeHeaderException
     */
    public function __construct($firstByte, $lastByte)
    {
        $this->firstByte = $firstByte === null ? $firstByte : (int)$firstByte;
        $this->lastByte = $lastByte === null ? $lastByte : (int)$lastByte;

        if ($this->firstByte === null && $this->lastByte === null) {
            throw new InvalidRangeHeaderException(
                'Both start and end position specifiers empty'
            );
        } else if ($this->firstByte < 0 || $this->lastByte < 0) {
            throw new InvalidRangeHeaderException(
                'Position specifiers cannot be negative'
            );
        } else if ($this->lastByte !== null && $this->lastByte < $this->firstByte) {
            throw new InvalidRangeHeaderException(
                'Last byte cannot be less than first byte'
            );
        }
    }

    /**
     * Get the start position when this range is applied to a file of the specified size
     *
     * @param int $fileSize
     * @return int
     * @throws UnsatisfiableRangeException
     */
    public function getStartPosition($fileSize)
    {
        $size = (int)$fileSize;

        if ($this->firstByte === null) {
            return ($size - 1) - $this->lastByte;
        }

        if ($size <= $this->firstByte) {
            throw new UnsatisfiableRangeException(
                'Start position is after the end of the file'
            );
        }

        return $this->firstByte;
    }

    /**
     * Get the end position when this range is applied to a file of the specified size
     *
     * @param int $fileSize
     * @return int
     * @throws UnsatisfiableRangeException
     */
    public function getEndPosition($fileSize)
    {
        $size = (int)$fileSize;

        if ($this->lastByte === null) {
            return $size - 1;
        }

        if ($size <= $this->lastByte) {
            throw new UnsatisfiableRangeException(
                'End position is after the end of the file'
            );
        }

        return $this->lastByte;
    }

    /**
     * Get the length when this range is applied to a file of the specified size
     *
     * @param int $fileSize
     * @return int
     * @throws UnsatisfiableRangeException
     */
    public function getLength($fileSize)
    {
        $size = (int)$fileSize;

        return $this->getEndPosition($size) - $this->getStartPosition($size) + 1;
    }

    /**
     * Get a Content-Range header corresponding to this Range and the specified file
     * size
     *
     * @param int $fileSize
     * @return string
     */
    public function getContentRangeHeader($fileSize)
    {
        return 'bytes ' . $this->getStartPosition($fileSize) . '-'
             . $this->getEndPosition($fileSize) . '/' . $fileSize;
    }
}

class PartialFileServlet
{
    /**
     * The range header on which the data transmission will be based
     *
     * @var RangeHeader|null
     */
    private $range;

    /**
     * @param RangeHeader $range Range header on which the transmission will be based
     */
    public function __construct(RangeHeader $range = null)
    {
        $this->range = $range;
    }

    /**
     * Send part of the data in a seekable stream resource to the output buffer
     *
     * @param resource $fp Stream resource to read data from
     * @param int $start Position in the stream to start reading
     * @param int $length Number of bytes to read
     * @param int $chunkSize Maximum bytes to read from the file in a single operation
     */
    private function sendDataRange($fp, $start, $length, $chunkSize = 8192)
    {
        if ($start > 0) {
            fseek($fp, $start, SEEK_SET);
        }

        while ($length) {
            $read = ($length > $chunkSize) ? $chunkSize : $length;
            $length -= $read;
            echo fread($fp, $read);
        }
    }

    /**
     * Send the headers that are included regardless of whether a range was requested
     *
     * @param string $fileName
     * @param int $contentLength
     * @param string $contentType
     */
    private function sendDownloadHeaders($fileName, $contentLength, $contentType)
    {
        header('Content-Type: ' . $contentType);
        header('Content-Length: ' . $contentLength);
        header('Content-Disposition: attachment; filename="' . $fileName . '"');
        header('Accept-Ranges: bytes');
    }

    /**
     * Send data from a file based on the current Range header
     *
     * @param string $path Local file system path to serve
     * @param string $contentType MIME type of the data stream
     */
    public function sendFile($path, $contentType = 'application/octet-stream')
    {
        // Make sure the file exists and is a file, otherwise we are wasting our time
        $localPath = realpath($path);
        if ($localPath === false || !is_file($localPath)) {
            throw new NonExistentFileException(
                $path . ' does not exist or is not a file'
            );
        }

        // Make sure we can open the file for reading
        if (!$fp = fopen($localPath, 'r')) {
            throw new UnreadableFileException(
                'Failed to open ' . $localPath . ' for reading'
            );
        }

        $fileSize = filesize($localPath);

        if ($this->range == null) {
            // No range requested, just send the whole file
            header('HTTP/1.1 200 OK');
            $this->sendDownloadHeaders(basename($localPath), $fileSize, $contentType);

            fpassthru($fp);
        } else {
            // Send the request range
            header('HTTP/1.1 206 Partial Content');
            header('Content-Range: ' . $this->range->getContentRangeHeader($fileSize));
            $this->sendDownloadHeaders(
                basename($localPath),
                $this->range->getLength($fileSize),
                $contentType
            );

            $this->sendDataRange(
                $fp,
                $this->range->getStartPosition($fileSize),
                $this->range->getLength($fileSize)
            );
        }

        fclose($fp);
    }
}

用法示例：

<?php

$path = '/local/path/to/file.ext';
$contentType = 'application/octet-stream';

// Avoid sending unexpected errors to the client - we should be serving a file,
// we don't want to corrupt the data we send
ini_set('display_errors', '0');

try {
    $rangeHeader = RangeHeader::createFromHeaderString(get_request_header('Range'));
    (new PartialFileServlet($rangeHeader))->sendFile($path, $contentType);
} catch (InvalidRangeHeaderException $e) {
    header("HTTP/1.1 400 Bad Request");
} catch (UnsatisfiableRangeException $e) {
    header("HTTP/1.1 416 Range Not Satisfiable");
} catch (NonExistentFileException $e) {
    header("HTTP/1.1 404 Not Found");
} catch (UnreadableFileException $e) {
    header("HTTP/1.1 500 Internal Server Error");
}

// It's usually a good idea to explicitly exit after sending a file to avoid sending any
// extra data on the end that might corrupt the file
exit;

Answer 3

是的。支持字节范围。请参阅 RFC 2616 第 14.35 节。

它基本上意味着您应该读取 Range 标头，并从指定的偏移量开始提供文件。

这意味着您不能使用 readfile()，因为它服务于整个文件。相反，首先使用 fopen()，然后使用 fseek() 到正确的位置，然后使用 fpassthru() 来提供文件。

Answer 4

这100%有效，超级检查一下
我正在使用它，没有任何问题了。

        /* Function: download with resume/speed/stream options */


         /* List of File Types */
        function fileTypes($extension){
            $fileTypes['swf'] = 'application/x-shockwave-flash';
            $fileTypes['pdf'] = 'application/pdf';
            $fileTypes['exe'] = 'application/octet-stream';
            $fileTypes['zip'] = 'application/zip';
            $fileTypes['doc'] = 'application/msword';
            $fileTypes['xls'] = 'application/vnd.ms-excel';
            $fileTypes['ppt'] = 'application/vnd.ms-powerpoint';
            $fileTypes['gif'] = 'image/gif';
            $fileTypes['png'] = 'image/png';
            $fileTypes['jpeg'] = 'image/jpg';
            $fileTypes['jpg'] = 'image/jpg';
            $fileTypes['rar'] = 'application/rar';

            $fileTypes['ra'] = 'audio/x-pn-realaudio';
            $fileTypes['ram'] = 'audio/x-pn-realaudio';
            $fileTypes['ogg'] = 'audio/x-pn-realaudio';

            $fileTypes['wav'] = 'video/x-msvideo';
            $fileTypes['wmv'] = 'video/x-msvideo';
            $fileTypes['avi'] = 'video/x-msvideo';
            $fileTypes['asf'] = 'video/x-msvideo';
            $fileTypes['divx'] = 'video/x-msvideo';

            $fileTypes['mp3'] = 'audio/mpeg';
            $fileTypes['mp4'] = 'audio/mpeg';
            $fileTypes['mpeg'] = 'video/mpeg';
            $fileTypes['mpg'] = 'video/mpeg';
            $fileTypes['mpe'] = 'video/mpeg';
            $fileTypes['mov'] = 'video/quicktime';
            $fileTypes['swf'] = 'video/quicktime';
            $fileTypes['3gp'] = 'video/quicktime';
            $fileTypes['m4a'] = 'video/quicktime';
            $fileTypes['aac'] = 'video/quicktime';
            $fileTypes['m3u'] = 'video/quicktime';
            return $fileTypes[$extention];
        };

        /*
          Parameters: downloadFile(File Location, File Name,
          max speed, is streaming
          If streaming - videos will show as videos, images as images
          instead of download prompt
         */

        function downloadFile($fileLocation, $fileName, $maxSpeed = 100, $doStream = false) {
            if (connection_status() != 0)
                return(false);
        //    in some old versions this can be pereferable to get extention
        //    $extension = strtolower(end(explode('.', $fileName)));
            $extension = pathinfo($fileName, PATHINFO_EXTENSION);

            $contentType = fileTypes($extension);
            header("Cache-Control: public");
            header("Content-Transfer-Encoding: binary\n");
            header('Content-Type: $contentType');

            $contentDisposition = 'attachment';

            if ($doStream == true) {
                /* extensions to stream */
                $array_listen = array('mp3', 'm3u', 'm4a', 'mid', 'ogg', 'ra', 'ram', 'wm',
                    'wav', 'wma', 'aac', '3gp', 'avi', 'mov', 'mp4', 'mpeg', 'mpg', 'swf', 'wmv', 'divx', 'asf');
                if (in_array($extension, $array_listen)) {
                    $contentDisposition = 'inline';
                }
            }

            if (strstr($_SERVER['HTTP_USER_AGENT'], "MSIE")) {
                $fileName = preg_replace('/\./', '%2e', $fileName, substr_count($fileName, '.') - 1);
                header("Content-Disposition: $contentDisposition;
                    filename=\"$fileName\"");
            } else {
                header("Content-Disposition: $contentDisposition;
                    filename=\"$fileName\"");
            }

            header("Accept-Ranges: bytes");
            $range = 0;
            $size = filesize($fileLocation);

            if (isset($_SERVER['HTTP_RANGE'])) {
                list($a, $range) = explode("=", $_SERVER['HTTP_RANGE']);
                str_replace($range, "-", $range);
                $size2 = $size - 1;
                $new_length = $size - $range;
                header("HTTP/1.1 206 Partial Content");
                header("Content-Length: $new_length");
                header("Content-Range: bytes $range$size2/$size");
            } else {
                $size2 = $size - 1;
                header("Content-Range: bytes 0-$size2/$size");
                header("Content-Length: " . $size);
            }

            if ($size == 0) {
                die('Zero byte file! Aborting download');
            }
            set_magic_quotes_runtime(0);
            $fp = fopen("$fileLocation", "rb");

            fseek($fp, $range);

            while (!feof($fp) and ( connection_status() == 0)) {
                set_time_limit(0);
                print(fread($fp, 1024 * $maxSpeed));
                flush();
                ob_flush();
                sleep(1);
            }
            fclose($fp);

            return((connection_status() == 0) and ! connection_aborted());
        }

        /* Implementation */
        // downloadFile('path_to_file/1.mp3', '1.mp3', 1024, false);

Answer 5

解决此问题的一个非常好的方法是使用 mod_xsendfile Apache 模块，而无需“编写自己的”PHP 代码。然后在 PHP 中，您只需设置适当的标头即可。 Apache 开始做它的事情了。

header("X-Sendfile: /path/to/file");
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; file=\"filename\"");

Answer 6

如果您愿意安装新的 PECL 模块，使用 PHP 支持可恢复下载的最简单方法是通过 http_send_file()，如以下

<?php
http_send_content_disposition("document.pdf", true);
http_send_content_type("application/pdf");
http_throttle(0.1, 2048);
http_send_file("../report.pdf");
?>

来源：http://www.php.net/manual/en/function.http-send-file.php

我们用它来提供数据库存储的内容，它的作用就像一个魅力！

Answer 7

是的，您可以使用 Range 标头。您需要向客户端提供 3 个以上的标头才能进行完整下载：

header ("Accept-Ranges: bytes");
header ("Content-Length: " . $fileSize);
header ("Content-Range: bytes 0-" . $fileSize - 1 . "/" . $fileSize . ";");

与中断下载相比，您需要通过以下方式检查范围请求标头：

$headers = getAllHeaders ();
$range = substr ($headers['Range'], '6');

在这种情况下，不要忘记使用 206 状态代码提供内容：

header ("HTTP/1.1 206 Partial content");
header ("Accept-Ranges: bytes");
header ("Content-Length: " . $remaining_length);
header ("Content-Range: bytes " . $start . "-" . $to . "/" . $fileSize . ";");

您将从请求标头获取 $start 和 $to 变量，并使用 fseek() 查找文件中的正确位置。

Answer 8

最上面的答案有各种错误。

1. 主要错误：它不能正确处理 Range 标头。 bytes ab 应该表示 [a, b] 而不是 [a, b)，并且 bytes a- 是没有处理。
2. 小错误：它不使用缓冲区来处理输出。这可能会消耗太多内存并导致大文件速度低下。

这是我修改后的代码：

// TODO: configurations here
$fileName = "File Name";
$file = "File Path";
$bufferSize = 2097152;

$filesize = filesize($file);
$offset = 0;
$length = $filesize;
if (isset($_SERVER['HTTP_RANGE'])) {
    // if the HTTP_RANGE header is set we're dealing with partial content
    // find the requested range
    // this might be too simplistic, apparently the client can request
    // multiple ranges, which can become pretty complex, so ignore it for now
    preg_match('/bytes=(\d+)-(\d+)?/', $_SERVER['HTTP_RANGE'], $matches);
    $offset = intval($matches[1]);
    $end = $matches[2] || $matches[2] === '0' ? intval($matches[2]) : $filesize - 1;
    $length = $end + 1 - $offset;
    // output the right headers for partial content
    header('HTTP/1.1 206 Partial Content');
    header("Content-Range: bytes $offset-$end/$filesize");
}
// output the regular HTTP headers
header('Content-Type: ' . mime_content_type($file));
header("Content-Length: $filesize");
header("Content-Disposition: attachment; filename=\"$fileName\"");
header('Accept-Ranges: bytes');

$file = fopen($file, 'r');
// seek to the requested offset, this is 0 if it's not a partial content request
fseek($file, $offset);
// don't forget to send the data too
ini_set('memory_limit', '-1');
while ($length >= $bufferSize)
{
    print(fread($file, $bufferSize));
    $length -= $bufferSize;
}
if ($length) print(fread($file, $length));
fclose($file);

Answer 9

这对我来说非常有效： https://github.com/pomle/php-serveFilePartial

Answer 10

启用小型 Composer 的类，其工作方式与 pecl http_send_file 相同。这意味着支持可恢复下载和限制。 https://github.com/diversen/http-send-file

Answer 11

您可以使用以下代码在任何浏览器上支持字节范围请求

    <?php
$file = 'YouTube360p.mp4';
$fileLoc = $file;
$filesize = filesize($file);
$offset = 0;
$fileLength = $filesize;
$length = $filesize - 1;

if ( isset($_SERVER['HTTP_RANGE']) ) {
    // if the HTTP_RANGE header is set we're dealing with partial content

    $partialContent = true;
    preg_match('/bytes=(\d+)-(\d+)?/', $_SERVER['HTTP_RANGE'], $matches);

    $offset = intval($matches[1]);
    $tempLength = intval($matches[2]) - 0;
    if($tempLength != 0)
    {
        $length = $tempLength;
    }
    $fileLength = ($length - $offset) + 1;
} else {
    $partialContent = false;
    $offset = $length;
}

$file = fopen($file, 'r');

// seek to the requested offset, this is 0 if it's not a partial content request
fseek($file, $offset);

$data = fread($file, $length);

fclose($file);

if ( $partialContent ) {
    // output the right headers for partial content
    header('HTTP/1.1 206 Partial Content');
}

// output the regular HTTP headers
header('Content-Type: ' . mime_content_type($fileLoc));
header('Content-Length: ' . $fileLength);
header('Content-Disposition: inline; filename="' . $file . '"');
header('Accept-Ranges: bytes');
header('Content-Range: bytes ' . $offset . '-' . $length . '/' . $filesize);

// don't forget to send the data too
print($data);
?>

Answer 12

HTTP 中的恢复下载是通过 Range 标头完成的。如果请求包含 Range 标头，并且其他指示符（例如 If-Match、If-Unmodified-Since）表明内容尚未自下载开始以来没有改变，您提供 206 响应代码（而不是 200），指示您在 Content-Range 标头中返回的字节范围，然后在响应体。

但我不知道如何在 PHP 中做到这一点。

Answer 13

谢谢西奥！你的方法不能直接用于流式传输 divx，因为我发现 divx 播放器正在发送类似 bytes=9932800 的范围 -

但它向我展示了如何做到这一点，所以谢谢：D

if(isset($_SERVER['HTTP_RANGE']))
{
    file_put_contents('showrange.txt',$_SERVER['HTTP_RANGE']);

Answer 14

我创建了一个用于提供文件的库，支持条件（不要再次下载文件，除非文件已更改）和范围（暂停和恢复下载）请求。它甚至可以与虚拟文件系统配合使用，例如 Flysystem。

在这里查看：FileWaiter

示例用法：

use Stadly\FileWaiter\Adapter\Local;
use Stadly\FileWaiter\File;
use Stadly\FileWaiter\Waiter;

$streamFactory = new \GuzzleHttp\Psr7\HttpFactory();                // Any PSR-17 compatible stream factory.
$file = new File(new Local('filename.txt', $streamFactory));        // Or another file adapter. See below.
$responseFactory = new \GuzzleHttp\Psr7\HttpFactory();              // Any PSR-17 compatible response factory.

$waiter = new Waiter($file, $responseFactory);

$request = \GuzzleHttp\Psr7\ServerRequest::fromGlobals();           // Any PSR-7 compatible server request.

$response = $waiter->handle($request);                              // The response is created by the response factory.

$emitter = new \Laminas\HttpHandlerRunner\Emitter\SapiEmitter();    // Any way of emitting PSR-7 responses.
$emitter->emit($response);
die();