pics/controllers/Download.php

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PHP
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<?php
/*****************************************************************************
* Download.php
* Contains the code to download an album.
*
* Kabuki CMS (C) 2013-2019, Aaron van Geffen
*****************************************************************************/
class Download
{
public function __construct()
{
// Ensure we're logged in at this point.
$user = Registry::get('user');
if (!$user->isLoggedIn())
throw new NotAllowedException();
if (!isset($_GET['tag']))
throw new UserFacingException('No album or tag has been specified for download.');
$tag = (int)$_GET['tag'];
$album = Tag::fromId($tag);
if (isset($_GET['by']) && ($user = Member::fromSlug($_GET['by'])) !== false)
$id_user_uploaded = $user->getUserId();
else
$id_user_uploaded = null;
if (isset($_SESSION['current_export']))
throw new UserFacingException('You can only export one album at the same time. Please wait until the other download finishes, or try again later.');
// So far so good?
$this->exportAlbum($album, $id_user_uploaded);
exit;
}
private function exportAlbum(Tag $album, $id_user_uploaded)
{
$files = [];
$album_ids = array_merge([$album->id_tag], $this->getChildAlbumIds($album->id_tag));
foreach ($album_ids as $album_id)
{
$iterator = AssetIterator::getByOptions([
'id_tag' => $album_id,
'id_user_uploaded' => $id_user_uploaded,
]);
while ($asset = $iterator->next())
$files[] = join(DIRECTORY_SEPARATOR, [$asset->getSubdir(), $asset->getFilename()]);
}
$descriptorspec = [
0 => ['pipe', 'r'], // STDIN
1 => ['pipe', 'w'], // STDOUT
];
// Prevent simultaneous exports.
$_SESSION['current_export'] = $album->id_tag;
// Allow new exports if the connection is terminated unexpectedly (e.g. when a user aborts a download).
register_shutdown_function(function() {
if (isset($_SESSION['current_export']))
unset($_SESSION['current_export']);
});
$command = 'tar -cf - -C ' . escapeshellarg(ASSETSDIR) . ' --null -T -';
$proc = proc_open($command, $descriptorspec, $pipes, ASSETSDIR);
if(!$proc)
throw new UnexpectedValueException('Could not execute TAR command');
if(!$pipes[0])
throw new UnexpectedValueException('Could not open pipe for STDIN');
if(!$pipes[1])
throw new UnexpectedValueException('Could not open pipe for STDOUT');
// STDOUT should not block.
stream_set_blocking($pipes[1], 0);
// Allow this the download to take its time...
set_time_limit(0);
header('Pragma: no-cache');
header('Content-Description: File Download');
header('Content-disposition: attachment; filename="' . $album->tag . '.tar"');
header('Content-Type: application/octet-stream');
header('Content-Transfer-Encoding: binary');
// Write filenames to include to STDIN, separated by null bytes.
foreach ($files as $file)
fwrite($pipes[0], $file . "\0");
// Close STDIN pipe to start archiving.
fclose($pipes[0]);
// At this point, end output buffering so we can enjoy more than ~62MB of photos.
ob_end_flush();
do
{
// Read STDOUT as `tar` is doing its work.
echo stream_get_contents($pipes[1], 4096);
// Are we still running?
$status = proc_get_status($proc);
}
while (!empty($status) && $status['running']);
// Close STDOUT pipe and clean up process.
fclose($pipes[1]);
proc_close($proc);
// Allow new exports from this point onward.
unset($_SESSION['current_export']);
}
private function getChildAlbumIds($parent_id)
{
$ids = [];
$albums = Tag::getAlbums($parent_id, 0, PHP_INT_MAX);
foreach ($albums as $album)
{
$ids[] = $album['id_tag'];
$ids = array_merge($ids, $this->getChildAlbumIds($album['id_tag']));
}
return $ids;
}
}