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<?php
/**
* SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
* SPDX-FileCopyrightText: 2016 ownCloud, Inc.
* SPDX-License-Identifier: AGPL-3.0-only
*/
namespace OC;
use OC\Files\Filesystem;
use OCP\Files\File;
use OCP\Files\Folder;
use OCP\Files\InvalidPathException;
use OCP\Files\IRootFolder;
use OCP\Files\NotFoundException;
use OCP\Files\NotPermittedException;
use OCP\IRequest;
use ownCloud\TarStreamer\TarStreamer;
use Psr\Log\LoggerInterface;
use ZipStreamer\ZipStreamer;
class Streamer {
// array of regexp. Matching user agents will get tar instead of zip
private array $preferTarFor = [ '/macintosh|mac os x/i' ];
// streamer instance
private $streamerInstance;
/**
* Streamer constructor.
*
* @param IRequest $request
* @param int|float $size The size of the files in bytes
* @param int $numberOfFiles The number of files (and directories) that will
* be included in the streamed file
*/
public function __construct(IRequest $request, int|float $size, int $numberOfFiles) {
/**
* zip32 constraints for a basic (without compression, volumes nor
* encryption) zip file according to the Zip specification:
* - No file size is larger than 4 bytes (file size < 4294967296); see
* 4.4.9 uncompressed size
* - The size of all files plus their local headers is not larger than
* 4 bytes; see 4.4.16 relative offset of local header and 4.4.24
* offset of start of central directory with respect to the starting
* disk number
* - The total number of entries (files and directories) in the zip file
* is not larger than 2 bytes (number of entries < 65536); see 4.4.22
* total number of entries in the central dir
* - The size of the central directory is not larger than 4 bytes; see
* 4.4.23 size of the central directory
*
* Due to all that, zip32 is used if the size is below 4GB and there are
* less than 65536 files; the margin between 4*1000^3 and 4*1024^3
* should give enough room for the extra zip metadata. Technically, it
* would still be possible to create an invalid zip32 file (for example,
* a zip file from files smaller than 4GB with a central directory
* larger than 4GiB), but it should not happen in the real world.
*
* We also have to check for a size above 0. As negative sizes could be
* from not fully scanned external storage. And then things fall apart
* if somebody tries to package to much.
*/
if ($size > 0 && $size < 4 * 1000 * 1000 * 1000 && $numberOfFiles < 65536) {
$this->streamerInstance = new ZipStreamer(['zip64' => false]);
} elseif ($request->isUserAgent($this->preferTarFor)) {
$this->streamerInstance = new TarStreamer();
} else {
$this->streamerInstance = new ZipStreamer(['zip64' => PHP_INT_SIZE !== 4]);
}
}
/**
* Send HTTP headers
* @param string $name
*/
public function sendHeaders($name) {
header('X-Accel-Buffering: no');
$extension = $this->streamerInstance instanceof ZipStreamer ? '.zip' : '.tar';
$fullName = $name . $extension;
$this->streamerInstance->sendHeaders($fullName);
}
/**
* Stream directory recursively
*
* @throws NotFoundException
* @throws NotPermittedException
* @throws InvalidPathException
*/
public function addDirRecursive(string $dir, string $internalDir = ''): void {
$dirname = basename($dir);
$rootDir = $internalDir . $dirname;
if (!empty($rootDir)) {
$this->streamerInstance->addEmptyDir($rootDir);
}
$internalDir .= $dirname . '/';
// prevent absolute dirs
$internalDir = ltrim($internalDir, '/');
$userFolder = \OC::$server->get(IRootFolder::class)->get(Filesystem::getRoot());
/** @var Folder $dirNode */
$dirNode = $userFolder->get($dir);
$files = $dirNode->getDirectoryListing();
/** @var LoggerInterface $logger */
$logger = \OC::$server->query(LoggerInterface::class);
foreach ($files as $file) {
if ($file instanceof File) {
try {
$fh = $file->fopen('r');
if ($fh === false) {
$logger->error('Unable to open file for stream: ' . print_r($file, true));
continue;
}
} catch (NotPermittedException $e) {
continue;
}
$this->addFileFromStream(
$fh,
$internalDir . $file->getName(),
$file->getSize(),
$file->getMTime()
);
fclose($fh);
} elseif ($file instanceof Folder) {
if ($file->isReadable()) {
$this->addDirRecursive($dir . '/' . $file->getName(), $internalDir);
}
}
}
}
/**
* Add a file to the archive at the specified location and file name.
*
* @param resource $stream Stream to read data from
* @param string $internalName Filepath and name to be used in the archive.
* @param int|float $size Filesize
* @param int|false $time File mtime as int, or false
* @return bool $success
*/
public function addFileFromStream($stream, string $internalName, int|float $size, $time): bool {
$options = [];
if ($time) {
$options = [
'timestamp' => $time
];
}
if ($this->streamerInstance instanceof ZipStreamer) {
return $this->streamerInstance->addFileFromStream($stream, $internalName, $options);
} else {
return $this->streamerInstance->addFileFromStream($stream, $internalName, $size, $options);
}
}
/**
* Add an empty directory entry to the archive.
*
* @param string $dirName Directory Path and name to be added to the archive.
* @return bool $success
*/
public function addEmptyDir($dirName) {
return $this->streamerInstance->addEmptyDir($dirName);
}
/**
* Close the archive.
* A closed archive can no longer have new files added to it. After
* closing, the file is completely written to the output stream.
* @return bool $success
*/
public function finalize() {
return $this->streamerInstance->finalize();
}
}
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