Merge pull request #22020 from nextcloud/feature/20918/calendar_search

Add Event and Task Backends for Unified Search

7 files changed, 711 insertions, 0 deletions

diff --git a/apps/dav/lib/AppInfo/Application.php b/apps/dav/lib/AppInfo/Application.php
index 6f2f7b29153..1bad3cb1eba 100644
--- a/apps/dav/lib/AppInfo/Application.php
+++ b/apps/dav/lib/AppInfo/Application.php
@@ -55,6 +55,8 @@ use OCA\DAV\CardDAV\PhotoCache;
 use OCA\DAV\CardDAV\SyncService;
 use OCA\DAV\HookManager;
 use OCA\DAV\Search\ContactsSearchProvider;
+use OCA\DAV\Search\EventsSearchProvider;
+use OCA\DAV\Search\TasksSearchProvider;
 use OCP\AppFramework\App;
 use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IBootstrap;
@@ -102,6 +104,8 @@ class Application extends App implements IBootstrap {
 		 * Register Search Providers
 		 */
 		$context->registerSearchProvider(ContactsSearchProvider::class);
+		$context->registerSearchProvider(EventsSearchProvider::class);
+		$context->registerSearchProvider(TasksSearchProvider::class);
 	}
 
 	public function boot(IBootContext $context): void {
diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index ddfb0a641e5..5cddf6e84b6 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -1670,6 +1670,124 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	}
 
 	/**
+	 * @param string $principalUri
+	 * @param string $pattern
+	 * @param array $componentTypes
+	 * @param array $searchProperties
+	 * @param array $searchParameters
+	 * @param array $options
+	 * @return array
+	 */
+	public function searchPrincipalUri(string $principalUri,
+									   string $pattern,
+									   array $componentTypes,
+									   array $searchProperties,
+									   array $searchParameters,
+									   array $options = []): array {
+		$escapePattern = !\array_key_exists('escape_like_param', $options) || $options['escape_like_param'] !== false;
+
+		$calendarObjectIdQuery = $this->db->getQueryBuilder();
+		$calendarOr = $calendarObjectIdQuery->expr()->orX();
+		$searchOr = $calendarObjectIdQuery->expr()->orX();
+
+		// Fetch calendars and subscription
+		$calendars = $this->getCalendarsForUser($principalUri);
+		$subscriptions = $this->getSubscriptionsForUser($principalUri);
+		foreach ($calendars as $calendar) {
+			$calendarAnd = $calendarObjectIdQuery->expr()->andX();
+			$calendarAnd->add($calendarObjectIdQuery->expr()->eq('cob.calendarid', $calendarObjectIdQuery->createNamedParameter((int)$calendar['id'])));
+			$calendarAnd->add($calendarObjectIdQuery->expr()->eq('cob.calendartype', $calendarObjectIdQuery->createNamedParameter(self::CALENDAR_TYPE_CALENDAR)));
+
+			// If it's shared, limit search to public events
+			if ($calendar['principaluri'] !== $calendar['{http://owncloud.org/ns}owner-principal']) {
+				$calendarAnd->add($calendarObjectIdQuery->expr()->eq('co.classification', $calendarObjectIdQuery->createNamedParameter(self::CLASSIFICATION_PUBLIC)));
+			}
+
+			$calendarOr->add($calendarAnd);
+		}
+		foreach ($subscriptions as $subscription) {
+			$subscriptionAnd = $calendarObjectIdQuery->expr()->andX();
+			$subscriptionAnd->add($calendarObjectIdQuery->expr()->eq('cob.calendarid', $calendarObjectIdQuery->createNamedParameter((int)$subscription['id'])));
+			$subscriptionAnd->add($calendarObjectIdQuery->expr()->eq('cob.calendartype', $calendarObjectIdQuery->createNamedParameter(self::CALENDAR_TYPE_SUBSCRIPTION)));
+
+			// If it's shared, limit search to public events
+			if ($subscription['principaluri'] !== $subscription['{http://owncloud.org/ns}owner-principal']) {
+				$subscriptionAnd->add($calendarObjectIdQuery->expr()->eq('co.classification', $calendarObjectIdQuery->createNamedParameter(self::CLASSIFICATION_PUBLIC)));
+			}
+
+			$calendarOr->add($subscriptionAnd);
+		}
+
+		foreach ($searchProperties as $property) {
+			$propertyAnd = $calendarObjectIdQuery->expr()->andX();
+			$propertyAnd->add($calendarObjectIdQuery->expr()->eq('cob.name', $calendarObjectIdQuery->createNamedParameter($property, IQueryBuilder::PARAM_STR)));
+			$propertyAnd->add($calendarObjectIdQuery->expr()->isNull('cob.parameter'));
+
+			$searchOr->add($propertyAnd);
+		}
+		foreach ($searchParameters as $property => $parameter) {
+			$parameterAnd = $calendarObjectIdQuery->expr()->andX();
+			$parameterAnd->add($calendarObjectIdQuery->expr()->eq('cob.name', $calendarObjectIdQuery->createNamedParameter($property, IQueryBuilder::PARAM_STR)));
+			$parameterAnd->add($calendarObjectIdQuery->expr()->eq('cob.parameter', $calendarObjectIdQuery->createNamedParameter($parameter, IQueryBuilder::PARAM_STR)));
+
+			$searchOr->add($parameterAnd);
+		}
+
+		if ($calendarOr->count() === 0) {
+			return [];
+		}
+		if ($searchOr->count() === 0) {
+			return [];
+		}
+
+		$calendarObjectIdQuery->selectDistinct('cob.objectid')
+			->from($this->dbObjectPropertiesTable, 'cob')
+			->leftJoin('cob', 'calendarobjects', 'co', $calendarObjectIdQuery->expr()->eq('co.id', 'cob.objectid'))
+			->andWhere($calendarObjectIdQuery->expr()->in('co.componenttype', $calendarObjectIdQuery->createNamedParameter($componentTypes, IQueryBuilder::PARAM_STR_ARRAY)))
+			->andWhere($calendarOr)
+			->andWhere($searchOr);
+
+		if ('' !== $pattern) {
+			if (!$escapePattern) {
+				$calendarObjectIdQuery->andWhere($calendarObjectIdQuery->expr()->ilike('cob.value', $calendarObjectIdQuery->createNamedParameter($pattern)));
+			} else {
+				$calendarObjectIdQuery->andWhere($calendarObjectIdQuery->expr()->ilike('cob.value', $calendarObjectIdQuery->createNamedParameter('%' . $this->db->escapeLikeParameter($pattern) . '%')));
+			}
+		}
+
+		if (isset($options['limit'])) {
+			$calendarObjectIdQuery->setMaxResults($options['limit']);
+		}
+		if (isset($options['offset'])) {
+			$calendarObjectIdQuery->setFirstResult($options['offset']);
+		}
+
+		$result = $calendarObjectIdQuery->execute();
+		$matches = $result->fetchAll();
+		$result->closeCursor();
+		$matches = array_map(static function (array $match):int {
+			return (int) $match['objectid'];
+		}, $matches);
+
+		$query = $this->db->getQueryBuilder();
+		$query->select('calendardata', 'uri', 'calendarid', 'calendartype')
+			->from('calendarobjects')
+			->where($query->expr()->in('id', $query->createNamedParameter($matches, IQueryBuilder::PARAM_INT_ARRAY)));
+
+		$result = $query->execute();
+		$calendarObjects = $result->fetchAll();
+		$result->closeCursor();
+
+		return array_map(function (array $array): array {
+			$array['calendarid'] = (int)$array['calendarid'];
+			$array['calendartype'] = (int)$array['calendartype'];
+			$array['calendardata'] = $this->readBlob($array['calendardata']);
+
+			return $array;
+		}, $calendarObjects);
+	}
+
+	/**
 	 * Searches through all of a users calendars and calendar objects to find
 	 * an object with a specific UID.
 	 *
diff --git a/apps/dav/lib/Search/ACalendarSearchProvider.php b/apps/dav/lib/Search/ACalendarSearchProvider.php
new file mode 100644
index 00000000000..56273fe17e4
--- /dev/null
+++ b/apps/dav/lib/Search/ACalendarSearchProvider.php
@@ -0,0 +1,138 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Search;
+
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCP\App\IAppManager;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use OCP\Search\IProvider;
+use Sabre\VObject\Component;
+use Sabre\VObject\Reader;
+
+/**
+ * Class ACalendarSearchProvider
+ *
+ * @package OCA\DAV\Search
+ */
+abstract class ACalendarSearchProvider implements IProvider {
+
+	/** @var IAppManager */
+	protected $appManager;
+
+	/** @var IL10N */
+	protected $l10n;
+
+	/** @var IURLGenerator */
+	protected $urlGenerator;
+
+	/** @var CalDavBackend */
+	protected $backend;
+
+	/**
+	 * ACalendarSearchProvider constructor.
+	 *
+	 * @param IAppManager $appManager
+	 * @param IL10N $l10n
+	 * @param IURLGenerator $urlGenerator
+	 * @param CalDavBackend $backend
+	 */
+	public function __construct(IAppManager $appManager,
+								IL10N $l10n,
+								IURLGenerator $urlGenerator,
+								CalDavBackend $backend) {
+		$this->appManager = $appManager;
+		$this->l10n = $l10n;
+		$this->urlGenerator = $urlGenerator;
+		$this->backend = $backend;
+	}
+
+	/**
+	 * Get an associative array of calendars
+	 * calendarId => calendar
+	 *
+	 * @param string $principalUri
+	 * @return array
+	 */
+	protected function getSortedCalendars(string $principalUri): array {
+		$calendars = $this->backend->getCalendarsForUser($principalUri);
+		$calendarsById = [];
+		foreach ($calendars as $calendar) {
+			$calendarsById[(int) $calendar['id']] = $calendar;
+		}
+
+		return $calendarsById;
+	}
+
+	/**
+	 * Get an associative array of subscriptions
+	 * subscriptionId => subscription
+	 *
+	 * @param string $principalUri
+	 * @return array
+	 */
+	protected function getSortedSubscriptions(string $principalUri): array {
+		$subscriptions = $this->backend->getSubscriptionsForUser($principalUri);
+		$subscriptionsById = [];
+		foreach ($subscriptions as $subscription) {
+			$subscriptionsById[(int) $subscription['id']] = $subscription;
+		}
+
+		return $subscriptionsById;
+	}
+
+	/**
+	 * Returns the primary VEvent / VJournal / VTodo component
+	 * If it's a component with recurrence-ids, it will return
+	 * the primary component
+	 *
+	 * TODO: It would be a nice enhancement to show recurrence-exceptions
+	 * as individual search-results.
+	 * For now we will just display the primary element of a recurrence-set.
+	 *
+	 * @param string $calendarData
+	 * @param string $componentName
+	 * @return Component
+	 */
+	protected function getPrimaryComponent(string $calendarData, string $componentName): Component {
+		$vCalendar = Reader::read($calendarData, Reader::OPTION_FORGIVING);
+
+		$components = $vCalendar->select($componentName);
+		if (count($components) === 1) {
+			return $components[0];
+		}
+
+		// If it's a recurrence-set, take the primary element
+		foreach ($components as $component) {
+			/** @var Component $component */
+			if (!$component->{'RECURRENCE-ID'}) {
+				return $component;
+			}
+		}
+
+		// In case of error, just fallback to the first element in the set
+		return $components[0];
+	}
+}
diff --git a/apps/dav/lib/Search/EventsSearchProvider.php b/apps/dav/lib/Search/EventsSearchProvider.php
new file mode 100644
index 00000000000..43fc4f65dfc
--- /dev/null
+++ b/apps/dav/lib/Search/EventsSearchProvider.php
@@ -0,0 +1,231 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Search;
+
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCP\IUser;
+use OCP\Search\ISearchQuery;
+use OCP\Search\SearchResult;
+use Sabre\VObject\Component;
+use Sabre\VObject\DateTimeParser;
+use Sabre\VObject\Property;
+
+/**
+ * Class EventsSearchProvider
+ *
+ * @package OCA\DAV\Search
+ */
+class EventsSearchProvider extends ACalendarSearchProvider {
+
+	/**
+	 * @var string[]
+	 */
+	private static $searchProperties = [
+		'SUMMARY',
+		'LOCATION',
+		'DESCRIPTION',
+		'ATTENDEE',
+		'ORGANIZER',
+		'CATEGORIES',
+	];
+
+	/**
+	 * @var string[]
+	 */
+	private static $searchParameters = [
+		'ATTENDEE' => ['CN'],
+		'ORGANIZER' => ['CN'],
+	];
+
+	/**
+	 * @var string
+	 */
+	private static $componentType = 'VEVENT';
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getId(): string {
+		return 'calendar-dav';
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getName(): string {
+		return $this->l10n->t('Events');
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function search(IUser $user,
+						   ISearchQuery $query): SearchResult {
+		if (!$this->appManager->isEnabledForUser('calendar', $user)) {
+			return SearchResult::complete($this->getName(), []);
+		}
+
+		$principalUri = 'principals/users/' . $user->getUID();
+		$calendarsById = $this->getSortedCalendars($principalUri);
+		$subscriptionsById = $this->getSortedSubscriptions($principalUri);
+
+		$searchResults = $this->backend->searchPrincipalUri(
+			$principalUri,
+			$query->getTerm(),
+			[self::$componentType],
+			self::$searchProperties,
+			self::$searchParameters,
+			[
+				'limit' => $query->getLimit(),
+				'offset' => $query->getCursor(),
+			]
+		);
+		$formattedResults = \array_map(function (array $eventRow) use ($calendarsById, $subscriptionsById):EventsSearchResultEntry {
+			$component = $this->getPrimaryComponent($eventRow['calendardata'], self::$componentType);
+			$title = (string)($component->SUMMARY ?? $this->l10n->t('Untitled event'));
+			$subline = $this->generateSubline($component);
+
+			if ($eventRow['calendartype'] === CalDavBackend::CALENDAR_TYPE_CALENDAR) {
+				$calendar = $calendarsById[$eventRow['calendarid']];
+			} else {
+				$calendar = $subscriptionsById[$eventRow['calendarid']];
+			}
+			$resourceUrl = $this->getDeepLinkToCalendarApp($calendar['principaluri'], $calendar['uri'], $eventRow['uri']);
+
+			return new EventsSearchResultEntry('', $title, $subline, $resourceUrl, 'icon-calendar-dark', false);
+		}, $searchResults);
+
+		return SearchResult::paginated(
+			$this->getName(),
+			$formattedResults,
+			$query->getCursor() + count($formattedResults)
+		);
+	}
+
+	/**
+	 * @param string $principalUri
+	 * @param string $calendarUri
+	 * @param string $calendarObjectUri
+	 * @return string
+	 */
+	protected function getDeepLinkToCalendarApp(string $principalUri,
+												string $calendarUri,
+												string $calendarObjectUri): string {
+		$davUrl = $this->getDavUrlForCalendarObject($principalUri, $calendarUri, $calendarObjectUri);
+		// This route will automatically figure out what recurrence-id to open
+		return $this->urlGenerator->getAbsoluteURL(
+			$this->urlGenerator->linkToRoute('calendar.view.index')
+			. 'edit/'
+			. base64_encode($davUrl)
+		);
+	}
+
+	/**
+	 * @param string $principalUri
+	 * @param string $calendarUri
+	 * @param string $calendarObjectUri
+	 * @return string
+	 */
+	protected function getDavUrlForCalendarObject(string $principalUri,
+												  string $calendarUri,
+												  string $calendarObjectUri): string {
+		[,, $principalId] = explode('/', $principalUri, 3);
+
+		return $this->urlGenerator->linkTo('', 'remote.php') . '/dav/calendars/'
+			. $principalId . '/'
+			. $calendarUri . '/'
+			. $calendarObjectUri;
+	}
+
+	/**
+	 * @param Component $eventComponent
+	 * @return string
+	 */
+	protected function generateSubline(Component $eventComponent): string {
+		$dtStart = $eventComponent->DTSTART;
+		$dtEnd = $this->getDTEndForEvent($eventComponent);
+		$isAllDayEvent = $dtStart instanceof Property\ICalendar\Date;
+		$startDateTime = new \DateTime($dtStart->getDateTime()->format(\DateTime::ATOM));
+		$endDateTime = new \DateTime($dtEnd->getDateTime()->format(\DateTime::ATOM));
+
+		if ($isAllDayEvent) {
+			$endDateTime->modify('-1 day');
+			if ($this->isDayEqual($startDateTime, $endDateTime)) {
+				return $this->l10n->l('date', $startDateTime, ['width' => 'medium']);
+			}
+
+			$formattedStart = $this->l10n->l('date', $startDateTime, ['width' => 'medium']);
+			$formattedEnd = $this->l10n->l('date', $endDateTime, ['width' => 'medium']);
+			return "$formattedStart - $formattedEnd";
+		}
+
+		$formattedStartDate = $this->l10n->l('date', $startDateTime, ['width' => 'medium']);
+		$formattedEndDate = $this->l10n->l('date', $endDateTime, ['width' => 'medium']);
+		$formattedStartTime = $this->l10n->l('time', $startDateTime, ['width' => 'short']);
+		$formattedEndTime = $this->l10n->l('time', $endDateTime, ['width' => 'short']);
+
+		if ($this->isDayEqual($startDateTime, $endDateTime)) {
+			return "$formattedStartDate $formattedStartTime - $formattedEndTime";
+		}
+
+		return "$formattedStartDate $formattedStartTime - $formattedEndDate $formattedEndTime";
+	}
+
+	/**
+	 * @param Component $eventComponent
+	 * @return Property
+	 */
+	protected function getDTEndForEvent(Component $eventComponent):Property {
+		if (isset($eventComponent->DTEND)) {
+			$end = $eventComponent->DTEND;
+		} elseif (isset($eventComponent->DURATION)) {
+			$isFloating = $eventComponent->DTSTART->isFloating();
+			$end = clone $eventComponent->DTSTART;
+			$endDateTime = $end->getDateTime();
+			$endDateTime = $endDateTime->add(DateTimeParser::parse($eventComponent->DURATION->getValue()));
+			$end->setDateTime($endDateTime, $isFloating);
+		} elseif (!$eventComponent->DTSTART->hasTime()) {
+			$isFloating = $eventComponent->DTSTART->isFloating();
+			$end = clone $eventComponent->DTSTART;
+			$endDateTime = $end->getDateTime();
+			$endDateTime = $endDateTime->modify('+1 day');
+			$end->setDateTime($endDateTime, $isFloating);
+		} else {
+			$end = clone $eventComponent->DTSTART;
+		}
+
+		return $end;
+	}
+
+	/**
+	 * @param \DateTime $dtStart
+	 * @param \DateTime $dtEnd
+	 * @return bool
+	 */
+	protected function isDayEqual(\DateTime $dtStart,
+								  \DateTime $dtEnd) {
+		return $dtStart->format('Y-m-d') === $dtEnd->format('Y-m-d');
+	}
+}
diff --git a/apps/dav/lib/Search/EventsSearchResultEntry.php b/apps/dav/lib/Search/EventsSearchResultEntry.php
new file mode 100644
index 00000000000..f70f10a6e75
--- /dev/null
+++ b/apps/dav/lib/Search/EventsSearchResultEntry.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Search;
+
+use OCP\Search\ASearchResultEntry;
+
+class EventsSearchResultEntry extends ASearchResultEntry {
+}
diff --git a/apps/dav/lib/Search/TasksSearchProvider.php b/apps/dav/lib/Search/TasksSearchProvider.php
new file mode 100644
index 00000000000..eee4694f08f
--- /dev/null
+++ b/apps/dav/lib/Search/TasksSearchProvider.php
@@ -0,0 +1,160 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Search;
+
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCP\IUser;
+use OCP\Search\ISearchQuery;
+use OCP\Search\SearchResult;
+use Sabre\VObject\Component;
+
+/**
+ * Class TasksSearchProvider
+ *
+ * @package OCA\DAV\Search
+ */
+class TasksSearchProvider extends ACalendarSearchProvider {
+
+	/**
+	 * @var string[]
+	 */
+	private static $searchProperties = [
+		'SUMMARY',
+		'DESCRIPTION',
+		'CATEGORIES',
+	];
+
+	/**
+	 * @var string[]
+	 */
+	private static $searchParameters = [];
+
+	/**
+	 * @var string
+	 */
+	private static $componentType = 'VTODO';
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getId(): string {
+		return 'tasks-dav';
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getName(): string {
+		return $this->l10n->t('Tasks');
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function search(IUser $user,
+						   ISearchQuery $query): SearchResult {
+		if (!$this->appManager->isEnabledForUser('tasks', $user)) {
+			return SearchResult::complete($this->getName(), []);
+		}
+
+		$principalUri = 'principals/users/' . $user->getUID();
+		$calendarsById = $this->getSortedCalendars($principalUri);
+		$subscriptionsById = $this->getSortedSubscriptions($principalUri);
+
+		$searchResults = $this->backend->searchPrincipalUri(
+			$principalUri,
+			$query->getTerm(),
+			[self::$componentType],
+			self::$searchProperties,
+			self::$searchParameters,
+			[
+				'limit' => $query->getLimit(),
+				'offset' => $query->getCursor(),
+			]
+		);
+		$formattedResults = \array_map(function (array $taskRow) use ($calendarsById, $subscriptionsById):TasksSearchResultEntry {
+			$component = $this->getPrimaryComponent($taskRow['calendardata'], self::$componentType);
+			$title = (string)($component->SUMMARY ?? $this->l10n->t('Untitled task'));
+			$subline = $this->generateSubline($component);
+
+			if ($taskRow['calendartype'] === CalDavBackend::CALENDAR_TYPE_CALENDAR) {
+				$calendar = $calendarsById[$taskRow['calendarid']];
+			} else {
+				$calendar = $subscriptionsById[$taskRow['calendarid']];
+			}
+			$resourceUrl = $this->getDeepLinkToTasksApp($calendar['uri'], $taskRow['uri']);
+
+			return new TasksSearchResultEntry('', $title, $subline, $resourceUrl, 'icon-checkmark', false);
+		}, $searchResults);
+
+		return SearchResult::paginated(
+			$this->getName(),
+			$formattedResults,
+			$query->getCursor() + count($formattedResults)
+		);
+	}
+
+	/**
+	 * @param string $calendarUri
+	 * @param string $taskUri
+	 * @return string
+	 */
+	protected function getDeepLinkToTasksApp(string $calendarUri,
+											 string $taskUri): string {
+		return $this->urlGenerator->getAbsoluteURL(
+			$this->urlGenerator->linkToRoute('tasks.page.index')
+			. '#/calendars/'
+			. $calendarUri
+			. '/tasks/'
+			. $taskUri
+		);
+	}
+
+	/**
+	 * @param Component $taskComponent
+	 * @return string
+	 */
+	protected function generateSubline(Component $taskComponent): string {
+		if ($taskComponent->COMPLETED) {
+			$completedDateTime = new \DateTime($taskComponent->COMPLETED->getDateTime()->format(\DateTime::ATOM));
+			$formattedDate = $this->l10n->l('date', $completedDateTime, ['width' => 'medium']);
+			return $this->l10n->t('Completed on %s', [$formattedDate]);
+		}
+
+		if ($taskComponent->DUE) {
+			$dueDateTime = new \DateTime($taskComponent->DUE->getDateTime()->format(\DateTime::ATOM));
+			$formattedDate = $this->l10n->l('date', $dueDateTime, ['width' => 'medium']);
+
+			if ($taskComponent->DUE->hasTime()) {
+				$formattedTime =  $this->l10n->l('time', $dueDateTime, ['width' => 'short']);
+				return $this->l10n->t('Due on %s by %s', [$formattedDate, $formattedTime]);
+			}
+
+			return $this->l10n->t('Due on %s', [$formattedDate]);
+		}
+
+		return '';
+	}
+}
diff --git a/apps/dav/lib/Search/TasksSearchResultEntry.php b/apps/dav/lib/Search/TasksSearchResultEntry.php
new file mode 100644
index 00000000000..ec58ba80af9
--- /dev/null
+++ b/apps/dav/lib/Search/TasksSearchResultEntry.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\Search;
+
+use OCP\Search\ASearchResultEntry;
+
+class TasksSearchResultEntry extends ASearchResultEntry {
+}