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<?php
/**
* @author Piotr Mrowczynski piotr@owncloud.com
*
* @copyright Copyright (c) 2019, ownCloud GmbH
* @license AGPL-3.0
*
* This code is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License, version 3,
* along with this program. If not, see <http://www.gnu.org/licenses/>
*
*/
namespace OCA\DAV\DAV;
use OCA\DAV\Connector\Sabre\Exception\Forbidden;
use OCA\DAV\Connector\Sabre\File as DavFile;
use OCA\DAV\Meta\MetaFile;
use OCP\Files\FileInfo;
use OCP\Files\NotFoundException;
use OCP\ILogger;
use Sabre\DAV\Server;
use Sabre\DAV\ServerPlugin;
use Sabre\HTTP\RequestInterface;
use Sabre\DAV\Exception\NotFound;
/**
* Sabre plugin for restricting file share receiver download:
*/
class ViewOnlyPlugin extends ServerPlugin {
/** @var Server $server */
private $server;
/** @var ILogger $logger */
private $logger;
/**
* @param ILogger $logger
*/
public function __construct(ILogger $logger) {
$this->logger = $logger;
}
/**
* This initializes the plugin.
*
* This function is called by Sabre\DAV\Server, after
* addPlugin is called.
*
* This method should set up the required event subscriptions.
*
* @param Server $server
* @return void
*/
public function initialize(Server $server) {
$this->server = $server;
//priority 90 to make sure the plugin is called before
//Sabre\DAV\CorePlugin::httpGet
$this->server->on('method:GET', [$this, 'checkViewOnly'], 90);
}
/**
* Disallow download via DAV Api in case file being received share
* and having special permission
*
* @param RequestInterface $request request object
* @return boolean
* @throws Forbidden
* @throws NotFoundException
*/
public function checkViewOnly(
RequestInterface $request
) {
$path = $request->getPath();
try {
$davNode = $this->server->tree->getNodeForPath($path);
if (!($davNode instanceof DavFile)) {
return true;
}
// Restrict view-only to nodes which are shared
$node = $davNode->getNode();
$storage = $node->getStorage();
// using string as we have no guarantee that "files_sharing" app is loaded
if (!$storage->instanceOfStorage('OCA\Files_Sharing\SharedStorage')) {
return true;
}
// Extract extra permissions
/** @var \OCA\Files_Sharing\SharedStorage $storage */
$share = $storage->getShare();
// Check if read-only and on whether permission can download is both set and disabled.
$canDownload = $share->getAttributes()->getAttribute('permissions', 'download');
if ($canDownload !== null && !$canDownload) {
throw new Forbidden('Access to this resource has been denied because it is in view-only mode.');
}
} catch (NotFound $e) {
$this->logger->warning($e->getMessage());
}
return true;
}
}
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