owncloud/core

<?php
/**
 * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Piotr Mrowczynski <piotr@owncloud.com>
 *
 * @copyright Copyright (c) 2018, 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\Connector\Sabre;

use OCP\Comments\ICommentsManager;
use OCP\IUserSession;
use Sabre\DAV\PropFind;
use Sabre\DAV\ServerPlugin;

class CommentPropertiesPlugin extends ServerPlugin {
    public const PROPERTY_NAME_HREF   = '{http://owncloud.org/ns}comments-href';
    public const PROPERTY_NAME_COUNT  = '{http://owncloud.org/ns}comments-count';
    public const PROPERTY_NAME_UNREAD = '{http://owncloud.org/ns}comments-unread';

    /** @var  \Sabre\DAV\Server */
    protected $server;

    /** @var ICommentsManager */
    private $commentsManager;

    /** @var IUserSession */
    private $userSession;

    /**
     * @var int[]
     */
    private $numberOfCommentsForNodes;

    public function __construct(ICommentsManager $commentsManager, IUserSession $userSession) {
        $this->commentsManager = $commentsManager;
        $this->userSession = $userSession;
    }

    /**
     * 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 \Sabre\DAV\Server $server
     * @return void
     */
    public function initialize(\Sabre\DAV\Server $server) {
        $this->server = $server;
        $this->server->on('propFind', [$this, 'handleGetProperties']);
    }

    /**
     * Adds tags and favorites properties to the response,
     * if requested.
     *
     * @param PropFind $propFind
     * @param \Sabre\DAV\INode $node
     * @return void
     */
    public function handleGetProperties(
        PropFind $propFind,
        \Sabre\DAV\INode $node
    ) {
        if (!($node instanceof File) && !($node instanceof Directory)) {
            return;
        }

        // Prefetch required data if we know that it is parent node
        if ($node instanceof \OCA\DAV\Connector\Sabre\Directory
            && $propFind->getDepth() !== 0
            && $propFind->getStatus(self::PROPERTY_NAME_UNREAD) !== null) {
            // Get ID of parent folder
            $folderNodeID = $node->getId();
            $nodeIdsArray = [$folderNodeID];
            $this->numberOfCommentsForNodes[$folderNodeID] = 0;

            // Get IDs for all children of the parent folder
            $children = $node->getChildren();
            foreach ($children as $childNode) {
                if (!($childNode instanceof \OCA\DAV\Connector\Sabre\Directory) &&
                    !($childNode instanceof \OCA\DAV\Connector\Sabre\File)) {
                    return;
                }
                // Put node ID into an array
                $nodeId = $childNode->getId();
                \array_push($nodeIdsArray, $nodeId);
                $this->numberOfCommentsForNodes[$nodeId] = 0;
            }

            // Get user session
            $user = $this->userSession->getUser();
            if ($user !== null) {
                // Fetch all unread comments with their nodeIDs
                $numberOfCommentsForNodes = $this->commentsManager->getNumberOfUnreadCommentsForNodes(
                    'files',
                    $nodeIdsArray,
                    $user
                );

                if ($numberOfCommentsForNodes !== null) {
                    // Map them to cached hash table
                    foreach ($numberOfCommentsForNodes as $nodeID => $numberOfCommentsForNode) {
                        $this->numberOfCommentsForNodes[$nodeID] = $numberOfCommentsForNode;
                    }
                }
            }
        }

        $propFind->handle(self::PROPERTY_NAME_COUNT, function () use ($node) {
            return $this->commentsManager->getNumberOfCommentsForObject('files', \strval($node->getId()));
        });

        $propFind->handle(self::PROPERTY_NAME_HREF, function () use ($node) {
            return $this->getCommentsLink($node);
        });

        $propFind->handle(self::PROPERTY_NAME_UNREAD, function () use ($node) {
            return $this->getUnreadCount($node);
        });
    }

    /**
     * returns a reference to the comments node
     *
     * @param Node $node
     * @return mixed|string
     */
    public function getCommentsLink(Node $node) {
        $href =  $this->server->getBaseUri();
        $entryPoint = \strpos($href, '/remote.php/');
        if ($entryPoint === false) {
            // in case we end up somewhere else, unexpectedly.
            return null;
        }
        $commentsPart = 'dav/comments/files/' . \rawurldecode($node->getId());
        $href = \substr_replace($href, $commentsPart, $entryPoint + \strlen('/remote.php/'));
        return $href;
    }

    /**
     * returns the number of unread comments for the currently logged in user
     * on the given file or directory node
     *
     * @param Node $node
     * @return Int|null
     */
    public function getUnreadCount(Node $node) {
        // Get user session
        $user = $this->userSession->getUser();
        $numberOfCommentsForNode = null;

        // Check if it is cached
        if (isset($this->numberOfCommentsForNodes[$node->getId()])) {
            $numberOfCommentsForNode = $this->numberOfCommentsForNodes[$node->getId()];
        } elseif ($user !== null) {
            // Fetch all unread comments for this specific NodeID
            $numberOfCommentsForNodes = $this->commentsManager->getNumberOfUnreadCommentsForNodes(
                'files',
                [$node->getId()],
                $user
            );

            // Initialize with 0 as in prefetch phase in handleGetProperties
            $numberOfCommentsForNode = 0;
            if (isset($numberOfCommentsForNodes[$node->getId()])) {
                $numberOfCommentsForNode = $numberOfCommentsForNodes[$node->getId()];
            }
        }
        
        return $numberOfCommentsForNode;
    }
}