使用PHP发送文件时可以继续下载吗？

我们使用PHP脚本来进行隧道文件下载，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，通过这个脚本传递的下载不能由最终用户恢复。

有没有什么办法来支持这种基于PHP的解决方案的可恢复下载？

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，如果接收到Range: bytes=xy头的请求（ x和y是数字），则解析客户端请求的范围，像往常一样打开文件，寻找x字节，然后发送下一个y – x字节。 还要将响应设置为HTTP/1.0 206 Partial Content 。

没有测试过任何东西，这可能或多或少地起作用：

 $filesize = filesize($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，我绝对忽视了一些潜在的错误来源，但这应该是一个开始。

这里有部分内容的描述，我在fread的文档页面找到了关于部分内容的一些信息。

Answer 2

编辑 2016/02 – 代码完全重写为一组模块化工具一个示例用法，而不是一个单一的功能。 下面评论中提到的更正已经被合并。

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经过测试的工作解决方案（很大程度上依赖于Theo的答案）处理可恢复的下载，这是一套独立的工具。 此代码需要PHP 5.4或更高版本。

这个解决方案仍然只能处理每个请求的一个范围，但是在任何情况下，我都可以想到一个标准的浏览器，这不会引起问题。

 <?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。 支持字节范围。 请参阅RFC 2616第14.35节 。

它基本上意味着你应该读取Range标题，并开始从指定的偏移量提供文件。

这意味着你不能使用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

这工作100％超级检查，我使用它，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); 

Answer 5

解决这个问题的一个非常好的方法就是使用mod_xsendfile Apache模块，而不必“滚动”自己的PHP代码。 然后在PHP中，您只需设置适当的标题。 Apache可以做到这一点。

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

Answer 6

如果你愿意安装一个新的PECL模块， 用PHP支持可恢复下载的最简单方法是通过http_send_file() ，像这样

 <?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

我们用它来服务数据库存储的内容，它就像一个魅力！

Answer 7

最重要的答案有各种各样的错误。

1. 主要的bug：它不能正确处理Range头。 bytes ab应该表示[a, b]而不是[a, b) ，并且不处理bytes a- 。
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，导致大文件速度较慢。

这是我修改的代码：

 // 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 8

是的，您可以使用Range标题。 您需要为客户端提供3个额外的头文件才能完整下载：

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

除了中断的下载，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，不要忘记用206状态码来提供内容：

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

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

Answer 9

小型作曲家启用类，其工作方式与pecl http_send_file相同。 这意味着支持可恢复的下载和节流。 https://github.com/diversen/http-send-file

Answer 10

在HTTP中恢复下载是通过Range标题完成的。 如果请求包含一个Range头，并且如果其他指示符（例如， If-Match ， If-Unmodified-Since ）表示自下载开始以来内容没有改变，则给出一个206响应代码（而不是200），指出您在Content-Range标题中返回的字节Content-Range ，然后在响应正文中提供该范围。

不过，我不知道如何在PHP中这样做。

Answer 11

感谢Theo！ 你的方法没有直接工作的流媒体divx，因为我发现divx播放器发送范围像字节= 9932800-

但它告诉我如何做到这一点，谢谢：D

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

Answer 12

这对我很好： https ： //github.com/pomle/php-serveFilePartial

Answer 13

您可以在任何浏览器中使用下面的代码来支持字节范围请求

  <?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); ?>