php 使用PHP发送文件时可恢复下载？
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Resumable downloads when using PHP to send the file?
提问by
We are using a PHP scripting for tunnelling file downloads, since we don't want to expose the absolute path of downloadable file:
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);
Unfortunately we noticed that downloads passed through this script can't be resumed by the end user.
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。
Is there any way to support resumable downloads with such a PHP-based solution?
有没有办法支持这种基于 PHP 的解决方案的可恢复下载？
回答by Theo
The first thing you need to do is to send the Accept-Ranges: bytesheader in all responses, to tell the client that you support partial content. Then, if request with a Range: bytes=x-y?header is received (with xand ybeing numbers) you parse the range the client is requesting, open the file as usual, seek xbytes ahead and send the next y- xbytes. Also set the response to HTTP/1.0 206 Partial Content.
您需要做的第一件事是Accept-Ranges: bytes在所有响应中发送标头，告诉客户端您支持部分内容。然后，如果有要求Range: bytes=x-y？头接收（用x和y为数字），解析客户端请求的范围，打开文件像往常一样，求x进取字节，发送下一个y-x字节。还将响应设置为HTTP/1.0 206 Partial Content.
Without having tested anything, this could work, more or less:
在没有测试任何东西的情况下，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);
I may have missed something obvious, and I have most definitely ignored some potential sources of errors, but it should be a start.
我可能错过了一些明显的东西，而且我绝对忽略了一些潜在的错误来源，但这应该是一个开始。
There's a description of partial content hereand I found some info on partial content on the documentation page for fread.
回答by DaveRandom
EDIT2017/01 - I wrote a library to do this in PHP >=7.0 https://github.com/DaveRandom/Resume
编辑2017/01 - 我写了一个库来在 PHP >=7.0 https://github.com/DaveRandom/Resume 中做到这一点
EDIT2016/02 - Code completely rewritten to a set of modular tools an an example usage, rather than a monolithic function. Corrections mentioned in comments below have been incorporated.
编辑2016/02 - 代码完全重写为一组模块化工具，一个示例用法，而不是一个整体功能。以下评论中提到的更正已被纳入。
A tested, working solution (based heavily on Theo's answer above) which deals with resumable downloads, in a set of a few standalone tools. This code requires PHP 5.4 or later.
一个经过测试的有效解决方案（主要基于上述 Theo 的回答），它在一组几个独立工具中处理可恢复的下载。此代码需要 PHP 5.4 或更高版本。
This solution can still only cope with one range per request, but under any circumstance with a standard browser that I can think of, this should not cause a problem.
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，这都不会导致问题。
<?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);
}
}
Example usage:
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 $e) {
header("HTTP/1.1 500 Internal Server Error");
}
// It's usually a good idea to explicitly exit after sending a file to avoid sending any
// extra data on the end that might corrupt the file
exit;
回答by user1524615
This works 100% super check it I am using it and no problems any more.
这工作 100% 超级检查它我正在使用它，没有问题了。
/* Function: download with resume/speed/stream options */
/* List of File Types */
function fileTypes($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);
回答by Sietse
Yes. Support byteranges. See RFC 2616 section 14.35.
是的。支持字节范围。请参阅RFC 2616 第 14.35 节。
It basically means that you should read the Rangeheader, and start serving the file from the specified offset.
这基本上意味着您应该读取Range标题，并从指定的偏移量开始提供文件。
This means that you can't use readfile(), since that serves the whole file. Instead, use fopen()first, then fseek()to the correct position, and then use fpassthru()to serve the file.
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。
回答by Jonathan Hawkes
A really nice way to solve this without having to "roll your own" PHP code is to use the mod_xsendfile Apache module. Then in PHP, you just set the appropriate headers. Apache gets to do its thing.
解决这个问题而不必“推出自己的”PHP 代码的一个非常好的方法是使用 mod_xsendfile Apache 模块。然后在 PHP 中，您只需设置适当的标题。Apache 开始做它的事情。
header("X-Sendfile: /path/to/file");
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; file=\"filename\"");
回答by Justin T.
If you're willing to install a new PECL module, the easiest way to support resumeable downloads with PHPis through http_send_file(), like this
如果您愿意安装新的 PECL 模块，支持使用 PHP 进行可恢复下载的最简单方法是通过http_send_file()，如下所示
<?php
http_send_content_disposition("document.pdf", true);
http_send_content_type("application/pdf");
http_throttle(0.1, 2048);
http_send_file("../report.pdf");
?>
source : http://www.php.net/manual/en/function.http-send-file.php
来源：http: //www.php.net/manual/en/function.http-send-file.php
We use it to serve database-stored content and it works like a charm !
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！
回答by Mygod
The top answer has various bugs.
最佳答案有各种错误。
- The major bug: It doesn't handle Range header correctly.
bytes a-bshould mean[a, b]instead of[a, b), andbytes a-is not handled. - The minor bug: It doesn't use buffer to handle output. This may consume too much memory and cause low speed for large files.
- 主要错误：它没有正确处理 Range 标头。
bytes a-b应该意味着[a, b]而不是[a, b)，并且bytes a-没有被处理。 - 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慢。
Here's my modified code:
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);
回答by Zsolt Szeberenyi
Yes, you can use the Range header for that. You need to give 3 more headers to the client for a full download:
是的，您可以为此使用 Range 标头。您需要向客户端提供另外 3 个标头以进行完整下载：
header ("Accept-Ranges: bytes");
header ("Content-Length: " . $fileSize);
header ("Content-Range: bytes 0-" . $fileSize - 1 . "/" . $fileSize . ";");
Than for an interrupted download you need to check the Range request header by:
对于中断的下载，您需要通过以下方式检查 Range 请求标头：
$headers = getAllHeaders ();
$range = substr ($headers['Range'], '6');
And in this case don't forget to serve the content with 206 status code:
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 . ";");
You'll get the $start and $to variables from the request header, and use fseek() to seek to the correct position in the file.
您将从请求标头中获取 $start 和 $to 变量，并使用 fseek() 寻找文件中的正确位置。
回答by dennis
Small composer enabled class which works the same way as pecl http_send_file. This means support for resumable downloads and throttle. https://github.com/diversen/http-send-file
启用小型作曲家的类，其工作方式与 pecl http_send_file 相同。这意味着支持可恢复下载和节流。https://github.com/diversen/http-send-file
回答by user3418767
This worked very well for me: https://github.com/pomle/php-serveFilePartial
这对我来说非常有效：https: //github.com/pomle/php-serveFilePartial
