Add activities for addressbook management

Signed-off-by: Joas Schilling <coding@schilljs.com>

apps/dav/appinfo/info.xml

@@ -76,6 +76,7 @@
 			<provider>OCA\DAV\CalDAV\Activity\Provider\Calendar</provider>
 			<provider>OCA\DAV\CalDAV\Activity\Provider\Event</provider>
 			<provider>OCA\DAV\CalDAV\Activity\Provider\Todo</provider>
+			<provider>OCA\DAV\CardDAV\Activity\Provider\Addressbook</provider>
 		</providers>
 	</activity>
 

apps/dav/composer/composer/autoload_classmap.php

@@ -85,7 +85,10 @@ return array(
     'OCA\\DAV\\CalDAV\\WebcalCaching\\Plugin' => $baseDir . '/../lib/CalDAV/WebcalCaching/Plugin.php',
     'OCA\\DAV\\CalDAV\\WebcalCaching\\RefreshWebcalService' => $baseDir . '/../lib/CalDAV/WebcalCaching/RefreshWebcalService.php',
     'OCA\\DAV\\Capabilities' => $baseDir . '/../lib/Capabilities.php',
+    'OCA\\DAV\\CardDAV\\Activity\\Backend' => $baseDir . '/../lib/CardDAV/Activity/Backend.php',
     'OCA\\DAV\\CardDAV\\Activity\\Filter' => $baseDir . '/../lib/CardDAV/Activity/Filter.php',
+    'OCA\\DAV\\CardDAV\\Activity\\Provider\\Addressbook' => $baseDir . '/../lib/CardDAV/Activity/Provider/Addressbook.php',
+    'OCA\\DAV\\CardDAV\\Activity\\Provider\\Base' => $baseDir . '/../lib/CardDAV/Activity/Provider/Base.php',
     'OCA\\DAV\\CardDAV\\Activity\\Setting' => $baseDir . '/../lib/CardDAV/Activity/Setting.php',
     'OCA\\DAV\\CardDAV\\AddressBook' => $baseDir . '/../lib/CardDAV/AddressBook.php',
     'OCA\\DAV\\CardDAV\\AddressBookImpl' => $baseDir . '/../lib/CardDAV/AddressBookImpl.php',
@@ -208,6 +211,7 @@ return array(
     'OCA\\DAV\\Files\\Sharing\\PublicLinkCheckPlugin' => $baseDir . '/../lib/Files/Sharing/PublicLinkCheckPlugin.php',
     'OCA\\DAV\\HookManager' => $baseDir . '/../lib/HookManager.php',
     'OCA\\DAV\\Listener\\ActivityUpdaterListener' => $baseDir . '/../lib/Listener/ActivityUpdaterListener.php',
+    'OCA\\DAV\\Listener\\AddressbookListener' => $baseDir . '/../lib/Listener/AddressbookListener.php',
     'OCA\\DAV\\Listener\\CalendarContactInteractionListener' => $baseDir . '/../lib/Listener/CalendarContactInteractionListener.php',
     'OCA\\DAV\\Listener\\CalendarDeletionDefaultUpdaterListener' => $baseDir . '/../lib/Listener/CalendarDeletionDefaultUpdaterListener.php',
     'OCA\\DAV\\Listener\\CalendarObjectReminderUpdaterListener' => $baseDir . '/../lib/Listener/CalendarObjectReminderUpdaterListener.php',

apps/dav/composer/composer/autoload_static.php

@@ -100,7 +100,10 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\CalDAV\\WebcalCaching\\Plugin' => __DIR__ . '/..' . '/../lib/CalDAV/WebcalCaching/Plugin.php',
         'OCA\\DAV\\CalDAV\\WebcalCaching\\RefreshWebcalService' => __DIR__ . '/..' . '/../lib/CalDAV/WebcalCaching/RefreshWebcalService.php',
         'OCA\\DAV\\Capabilities' => __DIR__ . '/..' . '/../lib/Capabilities.php',
+        'OCA\\DAV\\CardDAV\\Activity\\Backend' => __DIR__ . '/..' . '/../lib/CardDAV/Activity/Backend.php',
         'OCA\\DAV\\CardDAV\\Activity\\Filter' => __DIR__ . '/..' . '/../lib/CardDAV/Activity/Filter.php',
+        'OCA\\DAV\\CardDAV\\Activity\\Provider\\Addressbook' => __DIR__ . '/..' . '/../lib/CardDAV/Activity/Provider/Addressbook.php',
+        'OCA\\DAV\\CardDAV\\Activity\\Provider\\Base' => __DIR__ . '/..' . '/../lib/CardDAV/Activity/Provider/Base.php',
         'OCA\\DAV\\CardDAV\\Activity\\Setting' => __DIR__ . '/..' . '/../lib/CardDAV/Activity/Setting.php',
         'OCA\\DAV\\CardDAV\\AddressBook' => __DIR__ . '/..' . '/../lib/CardDAV/AddressBook.php',
         'OCA\\DAV\\CardDAV\\AddressBookImpl' => __DIR__ . '/..' . '/../lib/CardDAV/AddressBookImpl.php',
@@ -223,6 +226,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Files\\Sharing\\PublicLinkCheckPlugin' => __DIR__ . '/..' . '/../lib/Files/Sharing/PublicLinkCheckPlugin.php',
         'OCA\\DAV\\HookManager' => __DIR__ . '/..' . '/../lib/HookManager.php',
         'OCA\\DAV\\Listener\\ActivityUpdaterListener' => __DIR__ . '/..' . '/../lib/Listener/ActivityUpdaterListener.php',
+        'OCA\\DAV\\Listener\\AddressbookListener' => __DIR__ . '/..' . '/../lib/Listener/AddressbookListener.php',
         'OCA\\DAV\\Listener\\CalendarContactInteractionListener' => __DIR__ . '/..' . '/../lib/Listener/CalendarContactInteractionListener.php',
         'OCA\\DAV\\Listener\\CalendarDeletionDefaultUpdaterListener' => __DIR__ . '/..' . '/../lib/Listener/CalendarDeletionDefaultUpdaterListener.php',
         'OCA\\DAV\\Listener\\CalendarObjectReminderUpdaterListener' => __DIR__ . '/..' . '/../lib/Listener/CalendarObjectReminderUpdaterListener.php',

apps/dav/lib/AppInfo/Application.php

@@ -51,6 +51,10 @@ use OCA\DAV\CardDAV\CardDavBackend;
 use OCA\DAV\CardDAV\ContactsManager;
 use OCA\DAV\CardDAV\PhotoCache;
 use OCA\DAV\CardDAV\SyncService;
+use OCA\DAV\Events\AddressBookCreatedEvent;
+use OCA\DAV\Events\AddressBookDeletedEvent;
+use OCA\DAV\Events\AddressBookShareUpdatedEvent;
+use OCA\DAV\Events\AddressBookUpdatedEvent;
 use OCA\DAV\Events\CalendarCreatedEvent;
 use OCA\DAV\Events\CalendarDeletedEvent;
 use OCA\DAV\Events\CalendarObjectCreatedEvent;
@@ -60,6 +64,7 @@ use OCA\DAV\Events\CalendarShareUpdatedEvent;
 use OCA\DAV\Events\CalendarUpdatedEvent;
 use OCA\DAV\HookManager;
 use OCA\DAV\Listener\ActivityUpdaterListener;
+use OCA\DAV\Listener\AddressbookListener;
 use OCA\DAV\Listener\CalendarContactInteractionListener;
 use OCA\DAV\Listener\CalendarDeletionDefaultUpdaterListener;
 use OCA\DAV\Listener\CalendarObjectReminderUpdaterListener;
@@ -131,6 +136,12 @@ class Application extends App implements IBootstrap {
 		$context->registerEventListener(CalendarObjectDeletedEvent::class, CalendarObjectReminderUpdaterListener::class);
 		$context->registerEventListener(CalendarShareUpdatedEvent::class, CalendarContactInteractionListener::class);
 
+
+		$context->registerEventListener(AddressBookCreatedEvent::class, AddressbookListener::class);
+		$context->registerEventListener(AddressBookDeletedEvent::class, AddressbookListener::class);
+		$context->registerEventListener(AddressBookUpdatedEvent::class, AddressbookListener::class);
+		$context->registerEventListener(AddressBookShareUpdatedEvent::class, AddressbookListener::class);
+
 		$context->registerNotifierService(Notifier::class);
 	}
 

apps/dav/lib/CardDAV/Activity/Backend.php

@@ -0,0 +1,521 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Christoph Wurst <christoph@winzerhof-wurst.at>
+ * @author Joas Schilling <coding@schilljs.com>
+ * @author Roeland Jago Douma <roeland@famdouma.nl>
+ * @author Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * 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
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\DAV\CardDAV\Activity;
+
+use OCA\DAV\CardDAV\Activity\Provider\Addressbook;
+use OCP\Activity\IEvent;
+use OCP\Activity\IManager as IActivityManager;
+use OCP\App\IAppManager;
+use OCP\IGroup;
+use OCP\IGroupManager;
+use OCP\IUser;
+use OCP\IUserSession;
+use Sabre\CardDAV\Plugin;
+use Sabre\VObject\Reader;
+
+class Backend {
+
+	/** @var IActivityManager */
+	protected $activityManager;
+
+	/** @var IGroupManager */
+	protected $groupManager;
+
+	/** @var IUserSession */
+	protected $userSession;
+
+	/** @var IAppManager */
+	protected $appManager;
+
+	public function __construct(IActivityManager $activityManager,
+								IGroupManager $groupManager,
+								IUserSession $userSession,
+								IAppManager $appManager) {
+		$this->activityManager = $activityManager;
+		$this->groupManager = $groupManager;
+		$this->userSession = $userSession;
+		$this->appManager = $appManager;
+	}
+
+	/**
+	 * Creates activities when an addressbook was creates
+	 *
+	 * @param array $addressbookData
+	 */
+	public function onAddressbookCreate(array $addressbookData): void {
+		$this->triggerAddressbookActivity(Addressbook::SUBJECT_ADD, $addressbookData);
+	}
+
+	/**
+	 * Creates activities when a calendar was updated
+	 *
+	 * @param array $calendarData
+	 * @param array $shares
+	 * @param array $properties
+	 */
+	public function onAddressbookUpdate(array $calendarData, array $shares, array $properties): void {
+		$this->triggerAddressbookActivity(Addressbook::SUBJECT_UPDATE, $calendarData, $shares, $properties);
+	}
+
+	/**
+	 * Creates activities when a calendar was deleted
+	 *
+	 * @param array $calendarData
+	 * @param array $shares
+	 */
+	public function onAddressbookDelete(array $calendarData, array $shares): void {
+		$this->triggerAddressbookActivity(Addressbook::SUBJECT_DELETE, $calendarData, $shares);
+	}
+
+	/**
+	 * Creates activities for all related users when a calendar was touched
+	 *
+	 * @param string $action
+	 * @param array $addressbookData
+	 * @param array $shares
+	 * @param array $changedProperties
+	 */
+	protected function triggerAddressbookActivity($action, array $addressbookData, array $shares = [], array $changedProperties = []) {
+		if (!isset($addressbookData['principaluri'])) {
+			return;
+		}
+
+		$principal = explode('/', $addressbookData['principaluri']);
+		$owner = array_pop($principal);
+
+		$currentUser = $this->userSession->getUser();
+		if ($currentUser instanceof IUser) {
+			$currentUser = $currentUser->getUID();
+		} else {
+			$currentUser = $owner;
+		}
+
+		$event = $this->activityManager->generateEvent();
+		$event->setApp('dav')
+			->setObject('addressbook', (int) $addressbookData['id'])
+			->setType('addressbook')
+			->setAuthor($currentUser);
+
+		$changedVisibleInformation = array_intersect([
+			'{DAV:}displayname',
+			'{' . Plugin::NS_CARDDAV . '}addressbook-description',
+		], array_keys($changedProperties));
+
+		if (empty($shares) || ($action === Addressbook::SUBJECT_UPDATE && empty($changedVisibleInformation))) {
+			$users = [$owner];
+		} else {
+			$users = $this->getUsersForShares($shares);
+			$users[] = $owner;
+		}
+
+		foreach ($users as $user) {
+			$event->setAffectedUser($user)
+				->setSubject(
+					$user === $currentUser ? $action . '_self' : $action,
+					[
+						'actor' => $currentUser,
+						'addressbook' => [
+							'id' => (int) $addressbookData['id'],
+							'uri' => $addressbookData['uri'],
+							'name' => $addressbookData['{DAV:}displayname'],
+						],
+					]
+				);
+			$this->activityManager->publish($event);
+		}
+	}
+
+	/**
+	 * Creates activities for all related users when an addressbook was (un-)shared
+	 *
+	 * @param array $addressbookData
+	 * @param array $shares
+	 * @param array $add
+	 * @param array $remove
+	 */
+	public function onAddressbookUpdateShares(array $addressbookData, array $shares, array $add, array $remove) {
+		$principal = explode('/', $addressbookData['principaluri']);
+		$owner = $principal[2];
+
+		$currentUser = $this->userSession->getUser();
+		if ($currentUser instanceof IUser) {
+			$currentUser = $currentUser->getUID();
+		} else {
+			$currentUser = $owner;
+		}
+
+		$event = $this->activityManager->generateEvent();
+		$event->setApp('dav')
+			->setObject('addressbook', (int) $addressbookData['id'])
+			->setType('addressbook')
+			->setAuthor($currentUser);
+
+		foreach ($remove as $principal) {
+			// principal:principals/users/test
+			$parts = explode(':', $principal, 2);
+			if ($parts[0] !== 'principal') {
+				continue;
+			}
+			$principal = explode('/', $parts[1]);
+
+			if ($principal[1] === 'users') {
+				$this->triggerActivityUser(
+					$principal[2],
+					$event,
+					$addressbookData,
+					Addressbook::SUBJECT_UNSHARE_USER,
+					Addressbook::SUBJECT_DELETE . '_self'
+				);
+
+				if ($owner !== $principal[2]) {
+					$parameters = [
+						'actor' => $event->getAuthor(),
+						'addressbook' => [
+							'id' => (int) $addressbookData['id'],
+							'uri' => $addressbookData['uri'],
+							'name' => $addressbookData['{DAV:}displayname'],
+						],
+						'user' => $principal[2],
+					];
+
+					if ($owner === $event->getAuthor()) {
+						$subject = Addressbook::SUBJECT_UNSHARE_USER . '_you';
+					} elseif ($principal[2] === $event->getAuthor()) {
+						$subject = Addressbook::SUBJECT_UNSHARE_USER . '_self';
+					} else {
+						$event->setAffectedUser($event->getAuthor())
+							->setSubject(Addressbook::SUBJECT_UNSHARE_USER . '_you', $parameters);
+						$this->activityManager->publish($event);
+
+						$subject = Addressbook::SUBJECT_UNSHARE_USER . '_by';
+					}
+
+					$event->setAffectedUser($owner)
+						->setSubject($subject, $parameters);
+					$this->activityManager->publish($event);
+				}
+			} elseif ($principal[1] === 'groups') {
+				$this->triggerActivityGroup($principal[2], $event, $addressbookData, Addressbook::SUBJECT_UNSHARE_USER);
+
+				$parameters = [
+					'actor' => $event->getAuthor(),
+					'addressbook' => [
+						'id' => (int) $addressbookData['id'],
+						'uri' => $addressbookData['uri'],
+						'name' => $addressbookData['{DAV:}displayname'],
+					],
+					'group' => $principal[2],
+				];
+
+				if ($owner === $event->getAuthor()) {
+					$subject = Addressbook::SUBJECT_UNSHARE_GROUP . '_you';
+				} else {
+					$event->setAffectedUser($event->getAuthor())
+						->setSubject(Addressbook::SUBJECT_UNSHARE_GROUP . '_you', $parameters);
+					$this->activityManager->publish($event);
+
+					$subject = Addressbook::SUBJECT_UNSHARE_GROUP . '_by';
+				}
+
+				$event->setAffectedUser($owner)
+					->setSubject($subject, $parameters);
+				$this->activityManager->publish($event);
+			}
+		}
+
+		foreach ($add as $share) {
+			if ($this->isAlreadyShared($share['href'], $shares)) {
+				continue;
+			}
+
+			// principal:principals/users/test
+			$parts = explode(':', $share['href'], 2);
+			if ($parts[0] !== 'principal') {
+				continue;
+			}
+			$principal = explode('/', $parts[1]);
+
+			if ($principal[1] === 'users') {
+				$this->triggerActivityUser($principal[2], $event, $addressbookData, Addressbook::SUBJECT_SHARE_USER);
+
+				if ($owner !== $principal[2]) {
+					$parameters = [
+						'actor' => $event->getAuthor(),
+						'addressbook' => [
+							'id' => (int) $addressbookData['id'],
+							'uri' => $addressbookData['uri'],
+							'name' => $addressbookData['{DAV:}displayname'],
+						],
+						'user' => $principal[2],
+					];
+
+					if ($owner === $event->getAuthor()) {
+						$subject = Addressbook::SUBJECT_SHARE_USER . '_you';
+					} else {
+						$event->setAffectedUser($event->getAuthor())
+							->setSubject(Addressbook::SUBJECT_SHARE_USER . '_you', $parameters);
+						$this->activityManager->publish($event);
+
+						$subject = Addressbook::SUBJECT_SHARE_USER . '_by';
+					}
+
+					$event->setAffectedUser($owner)
+						->setSubject($subject, $parameters);
+					$this->activityManager->publish($event);
+				}
+			} elseif ($principal[1] === 'groups') {
+				$this->triggerActivityGroup($principal[2], $event, $addressbookData, Addressbook::SUBJECT_SHARE_USER);
+
+				$parameters = [
+					'actor' => $event->getAuthor(),
+					'addressbook' => [
+						'id' => (int) $addressbookData['id'],
+						'uri' => $addressbookData['uri'],
+						'name' => $addressbookData['{DAV:}displayname'],
+					],
+					'group' => $principal[2],
+				];
+
+				if ($owner === $event->getAuthor()) {
+					$subject = Addressbook::SUBJECT_SHARE_GROUP . '_you';
+				} else {
+					$event->setAffectedUser($event->getAuthor())
+						->setSubject(Addressbook::SUBJECT_SHARE_GROUP . '_you', $parameters);
+					$this->activityManager->publish($event);
+
+					$subject = Addressbook::SUBJECT_SHARE_GROUP . '_by';
+				}
+
+				$event->setAffectedUser($owner)
+					->setSubject($subject, $parameters);
+				$this->activityManager->publish($event);
+			}
+		}
+	}
+
+	/**
+	 * Checks if a calendar is already shared with a principal
+	 *
+	 * @param string $principal
+	 * @param array[] $shares
+	 * @return bool
+	 */
+	protected function isAlreadyShared(string $principal, array $shares): bool {
+		foreach ($shares as $share) {
+			if ($principal === $share['href']) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * Creates the given activity for all members of the given group
+	 *
+	 * @param string $gid
+	 * @param IEvent $event
+	 * @param array $properties
+	 * @param string $subject
+	 */
+	protected function triggerActivityGroup(string $gid, IEvent $event, array $properties, string $subject): void {
+		$group = $this->groupManager->get($gid);
+
+		if ($group instanceof IGroup) {
+			foreach ($group->getUsers() as $user) {
+				// Exclude current user
+				if ($user->getUID() !== $event->getAuthor()) {
+					$this->triggerActivityUser($user->getUID(), $event, $properties, $subject);
+				}
+			}
+		}
+	}
+
+	/**
+	 * Creates the given activity for the given user
+	 *
+	 * @param string $user
+	 * @param IEvent $event
+	 * @param array $properties
+	 * @param string $subject
+	 * @param string $subjectSelf
+	 */
+	protected function triggerActivityUser(string $user, IEvent $event, array $properties, string $subject, string $subjectSelf = ''): void {
+		$event->setAffectedUser($user)
+			->setSubject(
+				$user === $event->getAuthor() && $subjectSelf ? $subjectSelf : $subject,
+				[
+					'actor' => $event->getAuthor(),
+					'addressbook' => [
+						'id' => (int) $properties['id'],
+						'uri' => $properties['uri'],
+						'name' => $properties['{DAV:}displayname'],
+					],
+				]
+			);
+
+		$this->activityManager->publish($event);
+	}
+
+	/**
+	 * Creates activities when a calendar object was created/updated/deleted
+	 *
+	 * @param string $action
+	 * @param array $calendarData
+	 * @param array $shares
+	 * @param array $objectData
+	 */
+	public function onTouchCalendarObject($action, array $calendarData, array $shares, array $objectData) {
+		if (!isset($calendarData['principaluri'])) {
+			return;
+		}
+
+		$principal = explode('/', $calendarData['principaluri']);
+		$owner = array_pop($principal);
+
+		$currentUser = $this->userSession->getUser();
+		if ($currentUser instanceof IUser) {
+			$currentUser = $currentUser->getUID();
+		} else {
+			$currentUser = $owner;
+		}
+
+		$classification = $objectData['classification'] ?? CalDavBackend::CLASSIFICATION_PUBLIC;
+		$object = $this->getObjectNameAndType($objectData);
+		$action = $action . '_' . $object['type'];
+
+		if ($object['type'] === 'todo' && strpos($action, Event::SUBJECT_OBJECT_UPDATE) === 0 && $object['status'] === 'COMPLETED') {
+			$action .= '_completed';
+		} elseif ($object['type'] === 'todo' && strpos($action, Event::SUBJECT_OBJECT_UPDATE) === 0 && $object['status'] === 'NEEDS-ACTION') {
+			$action .= '_needs_action';
+		}
+
+		$event = $this->activityManager->generateEvent();
+		$event->setApp('dav')
+			->setObject('calendar', (int) $calendarData['id'])
+			->setType($object['type'] === 'event' ? 'calendar_event' : 'calendar_todo')
+			->setAuthor($currentUser);
+
+		$users = $this->getUsersForShares($shares);
+		$users[] = $owner;
+
+		// Users for share can return the owner itself if the calendar is published
+		foreach (array_unique($users) as $user) {
+			if ($classification === CalDavBackend::CLASSIFICATION_PRIVATE && $user !== $owner) {
+				// Private events are only shown to the owner
+				continue;
+			}
+
+			$params = [
+				'actor' => $event->getAuthor(),
+				'calendar' => [
+					'id' => (int) $calendarData['id'],
+					'uri' => $calendarData['uri'],
+					'name' => $calendarData['{DAV:}displayname'],
+				],
+				'object' => [
+					'id' => $object['id'],
+					'name' => $classification === CalDavBackend::CLASSIFICATION_CONFIDENTIAL && $user !== $owner ? 'Busy' : $object['name'],
+					'classified' => $classification === CalDavBackend::CLASSIFICATION_CONFIDENTIAL && $user !== $owner,
+				],
+			];
+
+			if ($object['type'] === 'event' && strpos($action, Event::SUBJECT_OBJECT_DELETE) === false && $this->appManager->isEnabledForUser('calendar')) {
+				$params['object']['link']['object_uri'] = $objectData['uri'];
+				$params['object']['link']['calendar_uri'] = $calendarData['uri'];
+				$params['object']['link']['owner'] = $owner;
+			}
+
+
+			$event->setAffectedUser($user)
+				->setSubject(
+					$user === $currentUser ? $action . '_self' : $action,
+					$params
+				);
+
+			$this->activityManager->publish($event);
+		}
+	}
+
+	/**
+	 * @param array $objectData
+	 * @return string[]|bool
+	 */
+	protected function getObjectNameAndType(array $objectData) {
+		$vObject = Reader::read($objectData['calendardata']);
+		$component = $componentType = null;
+		foreach ($vObject->getComponents() as $component) {
+			if (in_array($component->name, ['VEVENT', 'VTODO'])) {
+				$componentType = $component->name;
+				break;
+			}
+		}
+
+		if (!$componentType) {
+			// Calendar objects must have a VEVENT or VTODO component
+			return false;
+		}
+
+		if ($componentType === 'VEVENT') {
+			return ['id' => (string) $component->UID, 'name' => (string) $component->SUMMARY, 'type' => 'event'];
+		}
+		return ['id' => (string) $component->UID, 'name' => (string) $component->SUMMARY, 'type' => 'todo', 'status' => (string) $component->STATUS];
+	}
+
+	/**
+	 * Get all users that have access to a given calendar
+	 *
+	 * @param array $shares
+	 * @return string[]
+	 */
+	protected function getUsersForShares(array $shares) {
+		$users = $groups = [];
+		foreach ($shares as $share) {
+			$principal = explode('/', $share['{http://owncloud.org/ns}principal']);
+			if ($principal[1] === 'users') {
+				$users[] = $principal[2];
+			} elseif ($principal[1] === 'groups') {
+				$groups[] = $principal[2];
+			}
+		}
+
+		if (!empty($groups)) {
+			foreach ($groups as $gid) {
+				$group = $this->groupManager->get($gid);
+				if ($group instanceof IGroup) {
+					foreach ($group->getUsers() as $user) {
+						$users[] = $user->getUID();
+					}
+				}
+			}
+		}
+
+		return array_unique($users);
+	}
+}

apps/dav/lib/CardDAV/Activity/Provider/Addressbook.php

@@ -0,0 +1,203 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * 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
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\DAV\CardDAV\Activity\Provider;
+
+use OCP\Activity\IEvent;
+use OCP\Activity\IEventMerger;
+use OCP\Activity\IManager;
+use OCP\IGroupManager;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use OCP\IUserManager;
+use OCP\L10N\IFactory;
+
+class Addressbook extends Base {
+	public const SUBJECT_ADD = 'addressbook_add';
+	public const SUBJECT_UPDATE = 'addressbook_update';
+	public const SUBJECT_DELETE = 'addressbook_delete';
+	public const SUBJECT_SHARE_USER = 'addressbook_user_share';
+	public const SUBJECT_SHARE_GROUP = 'addressbook_group_share';
+	public const SUBJECT_UNSHARE_USER = 'addressbook_user_unshare';
+	public const SUBJECT_UNSHARE_GROUP = 'addressbook_group_unshare';
+
+	/** @var IFactory */
+	protected $languageFactory;
+
+	/** @var IL10N */
+	protected $l;
+
+	/** @var IManager */
+	protected $activityManager;
+
+	/** @var IEventMerger */
+	protected $eventMerger;
+
+	/**
+	 * @param IFactory $languageFactory
+	 * @param IURLGenerator $url
+	 * @param IManager $activityManager
+	 * @param IUserManager $userManager
+	 * @param IGroupManager $groupManager
+	 * @param IEventMerger $eventMerger
+	 */
+	public function __construct(IFactory $languageFactory,
+								IURLGenerator $url,
+								IManager $activityManager,
+								IUserManager $userManager,
+								IGroupManager $groupManager,
+								IEventMerger $eventMerger) {
+		parent::__construct($userManager, $groupManager, $url);
+		$this->languageFactory = $languageFactory;
+		$this->activityManager = $activityManager;
+		$this->eventMerger = $eventMerger;
+	}
+
+	/**
+	 * @param string $language
+	 * @param IEvent $event
+	 * @param IEvent|null $previousEvent
+	 * @return IEvent
+	 * @throws \InvalidArgumentException
+	 * @since 11.0.0
+	 */
+	public function parse($language, IEvent $event, IEvent $previousEvent = null): IEvent {
+		if ($event->getApp() !== 'dav' || $event->getType() !== 'addressbook') {
+			throw new \InvalidArgumentException();
+		}
+
+		$this->l = $this->languageFactory->get('dav', $language);
+
+		if ($this->activityManager->getRequirePNG()) {
+			$event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'places/contacts-dark.png')));
+		} else {
+			$event->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'places/contacts.svg')));
+		}
+
+		if ($event->getSubject() === self::SUBJECT_ADD) {
+			$subject = $this->l->t('{actor} created addressbook {addressbook}');
+		} elseif ($event->getSubject() === self::SUBJECT_ADD . '_self') {
+			$subject = $this->l->t('You created addressbook {addressbook}');
+		} elseif ($event->getSubject() === self::SUBJECT_DELETE) {
+			$subject = $this->l->t('{actor} deleted addressbook {addressbook}');
+		} elseif ($event->getSubject() === self::SUBJECT_DELETE . '_self') {
+			$subject = $this->l->t('You deleted addressbook {addressbook}');
+		} elseif ($event->getSubject() === self::SUBJECT_UPDATE) {
+			$subject = $this->l->t('{actor} updated addressbook {addressbook}');
+		} elseif ($event->getSubject() === self::SUBJECT_UPDATE . '_self') {
+			$subject = $this->l->t('You updated addressbook {addressbook}');
+		} elseif ($event->getSubject() === self::SUBJECT_SHARE_USER) {
+			$subject = $this->l->t('{actor} shared addressbook {addressbook} with you');
+		} elseif ($event->getSubject() === self::SUBJECT_SHARE_USER . '_you') {
+			$subject = $this->l->t('You shared addressbook {addressbook} with {user}');
+		} elseif ($event->getSubject() === self::SUBJECT_SHARE_USER . '_by') {
+			$subject = $this->l->t('{actor} shared addressbook {addressbook} with {user}');
+		} elseif ($event->getSubject() === self::SUBJECT_UNSHARE_USER) {
+			$subject = $this->l->t('{actor} unshared addressbook {addressbook} from you');
+		} elseif ($event->getSubject() === self::SUBJECT_UNSHARE_USER . '_you') {
+			$subject = $this->l->t('You unshared addressbook {addressbook} from {user}');
+		} elseif ($event->getSubject() === self::SUBJECT_UNSHARE_USER . '_by') {
+			$subject = $this->l->t('{actor} unshared addressbook {addressbook} from {user}');
+		} elseif ($event->getSubject() === self::SUBJECT_UNSHARE_USER . '_self') {
+			$subject = $this->l->t('{actor} unshared addressbook {addressbook} from themselves');
+		} elseif ($event->getSubject() === self::SUBJECT_SHARE_GROUP . '_you') {
+			$subject = $this->l->t('You shared addressbook {addressbook} with group {group}');
+		} elseif ($event->getSubject() === self::SUBJECT_SHARE_GROUP . '_by') {
+			$subject = $this->l->t('{actor} shared addressbook {addressbook} with group {group}');
+		} elseif ($event->getSubject() === self::SUBJECT_UNSHARE_GROUP . '_you') {
+			$subject = $this->l->t('You unshared addressbook {addressbook} from group {group}');
+		} elseif ($event->getSubject() === self::SUBJECT_UNSHARE_GROUP . '_by') {
+			$subject = $this->l->t('{actor} unshared addressbook {addressbook} from group {group}');
+		} else {
+			throw new \InvalidArgumentException();
+		}
+
+		$parsedParameters = $this->getParameters($event);
+		$this->setSubjects($event, $subject, $parsedParameters);
+
+		$event = $this->eventMerger->mergeEvents('addressbook', $event, $previousEvent);
+
+		if ($event->getChildEvent() === null) {
+			if (isset($parsedParameters['user'])) {
+				// Couldn't group by calendar, maybe we can group by users
+				$event = $this->eventMerger->mergeEvents('user', $event, $previousEvent);
+			} elseif (isset($parsedParameters['group'])) {
+				// Couldn't group by calendar, maybe we can group by groups
+				$event = $this->eventMerger->mergeEvents('group', $event, $previousEvent);
+			}
+		}
+
+		return $event;
+	}
+
+	protected function getParameters(IEvent $event): array {
+		$subject = $event->getSubject();
+		$parameters = $event->getSubjectParameters();
+
+		switch ($subject) {
+			case self::SUBJECT_ADD:
+			case self::SUBJECT_ADD . '_self':
+			case self::SUBJECT_DELETE:
+			case self::SUBJECT_DELETE . '_self':
+			case self::SUBJECT_UPDATE:
+			case self::SUBJECT_UPDATE . '_self':
+			case self::SUBJECT_SHARE_USER:
+			case self::SUBJECT_UNSHARE_USER:
+			case self::SUBJECT_UNSHARE_USER . '_self':
+				return [
+					'actor' => $this->generateUserParameter($parameters['actor']),
+					'addressbook' => $this->generateAddressbookParameter($parameters['addressbook'], $this->l),
+				];
+			case self::SUBJECT_SHARE_USER . '_you':
+			case self::SUBJECT_UNSHARE_USER . '_you':
+				return [
+					'addressbook' => $this->generateAddressbookParameter($parameters['addressbook'], $this->l),
+					'user' => $this->generateUserParameter($parameters['user']),
+				];
+			case self::SUBJECT_SHARE_USER . '_by':
+			case self::SUBJECT_UNSHARE_USER . '_by':
+				return [
+					'actor' => $this->generateUserParameter($parameters['actor']),
+					'addressbook' => $this->generateAddressbookParameter($parameters['addressbook'], $this->l),
+					'user' => $this->generateUserParameter($parameters['user']),
+				];
+			case self::SUBJECT_SHARE_GROUP . '_you':
+			case self::SUBJECT_UNSHARE_GROUP . '_you':
+				return [
+					'addressbook' => $this->generateAddressbookParameter($parameters['addressbook'], $this->l),
+					'group' => $this->generateGroupParameter($parameters['group']),
+				];
+			case self::SUBJECT_SHARE_GROUP . '_by':
+			case self::SUBJECT_UNSHARE_GROUP . '_by':
+				return [
+					'actor' => $this->generateUserParameter($parameters['actor']),
+					'addressbook' => $this->generateAddressbookParameter($parameters['addressbook'], $this->l),
+					'group' => $this->generateGroupParameter($parameters['group']),
+				];
+		}
+
+		throw new \InvalidArgumentException();
+	}
+}

apps/dav/lib/CardDAV/Activity/Provider/Base.php

@@ -0,0 +1,159 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * 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
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\DAV\CardDAV\Activity\Provider;
+
+use OCA\DAV\CardDAV\CardDavBackend;
+use OCP\Activity\IEvent;
+use OCP\Activity\IProvider;
+use OCP\IGroup;
+use OCP\IGroupManager;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use OCP\IUser;
+use OCP\IUserManager;
+
+abstract class Base implements IProvider {
+
+	/** @var IUserManager */
+	protected $userManager;
+
+	/** @var string[]  */
+	protected $userDisplayNames = [];
+
+	/** @var IGroupManager */
+	protected $groupManager;
+
+	/** @var string[] */
+	protected $groupDisplayNames = [];
+
+	/** @var IURLGenerator */
+	protected $url;
+
+	/**
+	 * @param IUserManager $userManager
+	 * @param IGroupManager $groupManager
+	 * @param IURLGenerator $urlGenerator
+	 */
+	public function __construct(IUserManager $userManager, IGroupManager $groupManager, IURLGenerator $urlGenerator) {
+		$this->userManager = $userManager;
+		$this->groupManager = $groupManager;
+		$this->url = $urlGenerator;
+	}
+
+	/**
+	 * @param IEvent $event
+	 * @param string $subject
+	 * @param array $parameters
+	 */
+	protected function setSubjects(IEvent $event, string $subject, array $parameters): void {
+		$placeholders = $replacements = [];
+		foreach ($parameters as $placeholder => $parameter) {
+			$placeholders[] = '{' . $placeholder . '}';
+			$replacements[] = $parameter['name'];
+		}
+
+		$event->setParsedSubject(str_replace($placeholders, $replacements, $subject))
+			->setRichSubject($subject, $parameters);
+	}
+
+	/**
+	 * @param array $data
+	 * @param IL10N $l
+	 * @return array
+	 */
+	protected function generateAddressbookParameter(array $data, IL10N $l): array {
+		if ($data['uri'] === CardDavBackend::PERSONAL_ADDRESSBOOK_URI &&
+			$data['name'] === CardDavBackend::PERSONAL_ADDRESSBOOK_NAME) {
+			return [
+				'type' => 'addressbook',
+				'id' => $data['id'],
+				'name' => $l->t('Personal'),
+			];
+		}
+
+		return [
+			'type' => 'addressbook',
+			'id' => $data['id'],
+			'name' => $data['name'],
+		];
+	}
+
+	/**
+	 * @param string $uid
+	 * @return array
+	 */
+	protected function generateUserParameter(string $uid): array {
+		if (!isset($this->userDisplayNames[$uid])) {
+			$this->userDisplayNames[$uid] = $this->getUserDisplayName($uid);
+		}
+
+		return [
+			'type' => 'user',
+			'id' => $uid,
+			'name' => $this->userDisplayNames[$uid],
+		];
+	}
+
+	/**
+	 * @param string $uid
+	 * @return string
+	 */
+	protected function getUserDisplayName(string $uid): string {
+		$user = $this->userManager->get($uid);
+		if ($user instanceof IUser) {
+			return $user->getDisplayName();
+		}
+		return $uid;
+	}
+
+	/**
+	 * @param string $gid
+	 * @return array
+	 */
+	protected function generateGroupParameter(string $gid): array {
+		if (!isset($this->groupDisplayNames[$gid])) {
+			$this->groupDisplayNames[$gid] = $this->getGroupDisplayName($gid);
+		}
+
+		return [
+			'type' => 'user-group',
+			'id' => $gid,
+			'name' => $this->groupDisplayNames[$gid],
+		];
+	}
+
+	/**
+	 * @param string $gid
+	 * @return string
+	 */
+	protected function getGroupDisplayName(string $gid): string {
+		$group = $this->groupManager->get($gid);
+		if ($group instanceof IGroup) {
+			return $group->getDisplayName();
+		}
+		return $gid;
+	}
+}

apps/dav/lib/Listener/AddressbookListener.php

@@ -0,0 +1,122 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2021 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * 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
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\DAV\Listener;
+
+use OCA\DAV\CardDAV\Activity\Backend as ActivityBackend;
+use OCA\DAV\Events\AddressBookCreatedEvent;
+use OCA\DAV\Events\AddressBookDeletedEvent;
+use OCA\DAV\Events\AddressBookShareUpdatedEvent;
+use OCA\DAV\Events\AddressBookUpdatedEvent;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use Psr\Log\LoggerInterface;
+use Throwable;
+use function sprintf;
+
+class AddressbookListener implements IEventListener {
+
+	/** @var ActivityBackend */
+	private $activityBackend;
+
+	/** @var LoggerInterface */
+	private $logger;
+
+	public function __construct(ActivityBackend $activityBackend,
+								LoggerInterface $logger) {
+		$this->activityBackend = $activityBackend;
+		$this->logger = $logger;
+	}
+
+	public function handle(Event $event): void {
+		if ($event instanceof AddressBookCreatedEvent) {
+			try {
+				$this->activityBackend->onAddressbookCreate(
+					$event->getAddressBookData()
+				);
+
+				$this->logger->debug(
+					sprintf('Activity generated for new addressbook %d', $event->getAddressBookId())
+				);
+			} catch (Throwable $e) {
+				// Any error with activities shouldn't abort the addressbook creation, so we just log it
+				$this->logger->error('Error generating activities for a new addressbook: ' . $e->getMessage(), [
+					'exception' => $e,
+				]);
+			}
+		} else if ($event instanceof AddressBookUpdatedEvent) {
+			try {
+				$this->activityBackend->onAddressbookUpdate(
+					$event->getAddressBookData(),
+					$event->getShares(),
+					$event->getMutations()
+				);
+
+				$this->logger->debug(
+					sprintf('Activity generated for changed addressbook %d', $event->getAddressBookId())
+				);
+			} catch (Throwable $e) {
+				// Any error with activities shouldn't abort the addressbook update, so we just log it
+				$this->logger->error('Error generating activities for a changed addressbook: ' . $e->getMessage(), [
+					'exception' => $e,
+				]);
+			}
+		} else if ($event instanceof AddressBookDeletedEvent) {
+			try {
+				$this->activityBackend->onAddressbookDelete(
+					$event->getAddressBookData(),
+					$event->getShares()
+				);
+
+				$this->logger->debug(
+					sprintf('Activity generated for deleted addressbook %d', $event->getAddressBookId())
+				);
+			} catch (Throwable $e) {
+				// Any error with activities shouldn't abort the addressbook deletion, so we just log it
+				$this->logger->error('Error generating activities for a deleted addressbook: ' . $e->getMessage(), [
+					'exception' => $e,
+				]);
+			}
+		} else if ($event instanceof AddressBookShareUpdatedEvent) {
+			try {
+				$this->activityBackend->onAddressbookUpdateShares(
+					$event->getAddressBookData(),
+					$event->getOldShares(),
+					$event->getAdded(),
+					$event->getRemoved()
+				);
+
+				$this->logger->debug(
+					sprintf('Activity generated for (un)sharing addressbook %d', $event->getAddressBookId())
+				);
+			} catch (Throwable $e) {
+				// Any error with activities shouldn't abort the addressbook creation, so we just log it
+				$this->logger->error('Error generating activities for (un)sharing addressbook: ' . $e->getMessage(), [
+					'exception' => $e,
+				]);
+			}
+		}
+	}
+}