Adding a custom webdav property which holds the list of contacts groups

apps/dav/lib/carddav/addressbook.php

@@ -161,4 +161,11 @@ class AddressBook extends \Sabre\CardDAV\AddressBook implements IShareable {
 		}
 		parent::delete();
 	}
+
+	public function getContactsGroups() {
+		/** @var CardDavBackend $cardDavBackend */
+		$cardDavBackend = $this->carddavBackend;
+
+		return $cardDavBackend->collectCardProperties($this->getResourceId(), 'CATEGORIES');
+	}
 }

apps/dav/lib/carddav/carddavbackend.php

@@ -29,6 +29,7 @@ use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCA\DAV\DAV\Sharing\Backend;
 use OCA\DAV\DAV\Sharing\IShareable;
 use OCP\IDBConnection;
+use PDO;
 use Sabre\CardDAV\Backend\BackendInterface;
 use Sabre\CardDAV\Backend\SyncSupport;
 use Sabre\CardDAV\Plugin;
@@ -761,6 +762,25 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 
 	}
 
+	/**
+	 * @param int $bookId
+	 * @param string $name
+	 * @return array
+	 */
+	public function collectCardProperties($bookId, $name) {
+		$query = $this->db->getQueryBuilder();
+		$result = $query->selectDistinct('value')
+			->from($this->dbCardsPropertiesTable)
+			->where($query->expr()->eq('name', $query->createNamedParameter($name)))
+			->andWhere($query->expr()->eq('addressbookid', $query->createNamedParameter($bookId)))
+			->execute();
+
+		$all = $result->fetchAll(PDO::FETCH_COLUMN);
+		$result->closeCursor();
+
+		return $all;
+	}
+
 	/**
 	 * get URI from a given contact
 	 *

apps/dav/lib/carddav/plugin.php

@@ -21,10 +21,19 @@
 
 namespace OCA\DAV\CardDAV;
 
+use OCA\DAV\CardDAV\Xml\Groups;
+use Sabre\DAV\INode;
+use Sabre\DAV\PropFind;
+use Sabre\DAV\Server;
 use Sabre\HTTP\URLUtil;
 
 class Plugin extends \Sabre\CardDAV\Plugin {
 
+	function initialize(Server $server) {
+		$server->on('propFind', [$this, 'propFind']);
+		parent::initialize($server);
+	}
+
 	/**
 	 * Returns the addressbook home for a given principal
 	 *
@@ -33,15 +42,34 @@ class Plugin extends \Sabre\CardDAV\Plugin {
 	 */
 	protected function getAddressbookHomeForPrincipal($principal) {
 
-		if (strrpos($principal, 'principals/users', -strlen($principal)) !== FALSE) {
+		if (strrpos($principal, 'principals/users', -strlen($principal)) !== false) {
 			list(, $principalId) = URLUtil::splitPath($principal);
 			return self::ADDRESSBOOK_ROOT . '/users/' . $principalId;
 		}
-		if (strrpos($principal, 'principals/system', -strlen($principal)) !== FALSE) {
+		if (strrpos($principal, 'principals/system', -strlen($principal)) !== false) {
 			list(, $principalId) = URLUtil::splitPath($principal);
 			return self::ADDRESSBOOK_ROOT . '/system/' . $principalId;
 		}
 
 		throw new \LogicException('This is not supposed to happen');
 	}
+
+	/**
+	 * Adds all CardDAV-specific properties
+	 *
+	 * @param PropFind $propFind
+	 * @param INode $node
+	 * @return void
+	 */
+	function propFind(PropFind $propFind, INode $node) {
+
+		$ns = '{http://owncloud.org/ns}';
+
+		if ($node instanceof AddressBook) {
+
+			$propFind->handle($ns . 'groups', function () use ($node) {
+				return new Groups($node->getContactsGroups());
+			});
+		}
+	}
 }

apps/dav/lib/carddav/xml/groups.php

@@ -0,0 +1,45 @@
+<?php
+/**
+ * @author Thomas Müller <thomas.mueller@tmit.eu>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @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\CardDAV\Xml;
+
+use Sabre\Xml\XmlSerializable;
+use Sabre\Xml\Element;
+use Sabre\Xml\Writer;
+
+class Groups implements XmlSerializable {
+	const NS_OWNCLOUD = 'http://owncloud.org/ns';
+
+	/** @var string[] of TYPE:CHECKSUM */
+	private $groups;
+
+	/**
+	 * @param string $groups
+	 */
+	public function __construct($groups) {
+		$this->groups = $groups;
+	}
+
+	function xmlSerialize(Writer $writer) {
+		foreach ($this->groups as $group) {
+			$writer->writeElement('{' . self::NS_OWNCLOUD . '}group', $group);
+		}
+	}
+}

apps/dav/tests/unit/carddav/carddavbackendtest.php

@@ -609,4 +609,21 @@ class CardDavBackendTest extends TestCase {
 		$this->assertEmpty($this->backend->getContact('uri'));
 	}
 
+	public function testCollectCardProperties() {
+		$query = $this->db->getQueryBuilder();
+		$query->insert($this->dbCardsPropertiesTable)
+			->values(
+				[
+					'addressbookid' => $query->createNamedParameter(666),
+					'cardid' => $query->createNamedParameter(777),
+					'name' => $query->createNamedParameter('FN'),
+					'value' => $query->createNamedParameter('John Doe'),
+					'preferred' => $query->createNamedParameter(0)
+				]
+			)
+		->execute();
+
+		$result = $this->backend->collectCardProperties(666, 'FN');
+		$this->assertEquals(['John Doe'], $result);
+	}
 }