basic notify_push usage with session handling (rebased)

Signed-off-by: chandi Langecker <git@chandi.it>

appinfo/routes.php

@@ -82,6 +82,11 @@ return [
 		['name' => 'label#update', 'url' => '/labels/{labelId}', 'verb' => 'PUT'],
 		['name' => 'label#delete', 'url' => '/labels/{labelId}', 'verb' => 'DELETE'],
 
+		// sessions
+		['name' => 'Session#create', 'url' => '/session/create', 'verb' => 'PUT'],
+		['name' => 'Session#sync', 'url' => '/session/sync', 'verb' => 'POST'],
+		['name' => 'Session#close', 'url' => '/session/close', 'verb' => 'POST'],
+
 		// api
 		['name' => 'board_api#index', 'url' => '/api/v{apiVersion}/boards', 'verb' => 'GET'],
 		['name' => 'board_api#get', 'url' => '/api/v{apiVersion}/boards/{boardId}', 'verb' => 'GET'],

lib/AppInfo/Application.php

@@ -40,6 +40,8 @@ use OCA\Deck\Event\AclUpdatedEvent;
 use OCA\Deck\Event\CardCreatedEvent;
 use OCA\Deck\Event\CardDeletedEvent;
 use OCA\Deck\Event\CardUpdatedEvent;
+use OCA\Deck\Event\SessionClosedEvent;
+use OCA\Deck\Event\SessionCreatedEvent;
 use OCA\Deck\Listeners\BeforeTemplateRenderedListener;
 use OCA\Deck\Listeners\ParticipantCleanupListener;
 use OCA\Deck\Listeners\FullTextSearchEventListener;
@@ -51,8 +53,10 @@ use OCA\Deck\Reference\CardReferenceProvider;
 use OCA\Deck\Search\CardCommentProvider;
 use OCA\Deck\Search\DeckProvider;
 use OCA\Deck\Service\PermissionService;
+use OCA\Deck\Service\SessionService;
 use OCA\Deck\Sharing\DeckShareProvider;
 use OCA\Deck\Sharing\Listener;
+use OCA\NotifyPush\Queue\IQueue;
 use OCP\AppFramework\App;
 use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IBootstrap;
@@ -96,6 +100,7 @@ class Application extends App implements IBootstrap {
 		$context->injectFn(Closure::fromCallable([$this, 'registerCommentsEventHandler']));
 		$context->injectFn(Closure::fromCallable([$this, 'registerNotifications']));
 		$context->injectFn(Closure::fromCallable([$this, 'registerCollaborationResources']));
+		$context->injectFn(Closure::fromCallable([$this, 'registerSessionListener']));
 
 		$context->injectFn(function (IManager $shareManager) {
 			$shareManager->registerShareProvider(DeckShareProvider::class);
@@ -188,4 +193,33 @@ class Application extends App implements IBootstrap {
 			Util::addScript('deck', 'deck-collections');
 		});
 	}
+
+	protected function registerSessionListener(IEventDispatcher $eventDispatcher): void {
+		$container = $this->getContainer();
+
+		try {
+			$queue = $container->get(IQueue::class);
+		} catch (\Exception $e) {
+			// most likely notify_push is not installed.
+			return;
+		}
+
+		// if SessionService is injected via function parameters, tests throw following error:
+		// "OCA\Deck\NoPermissionException: Creating boards has been disabled for your account."
+		// doing it this way it somehow works
+		$sessionService = $container->get(SessionService::class);
+
+		
+		$eventDispatcher->addListener(SessionCreatedEvent::class, function (SessionCreatedEvent $event) use ($sessionService, $queue) {
+			$sessionService->notifyAllSessions($queue, $event->getBoardId(), "DeckBoardUpdate", $event->getUserId(), [
+				"id" => $event->getBoardId()
+			]);
+		});
+
+		$eventDispatcher->addListener(SessionClosedEvent::class, function (SessionClosedEvent $event) use ($sessionService, $queue) {
+			$sessionService->notifyAllSessions($queue, $event->getBoardId(), "DeckBoardUpdate", $event->getUserId(), [
+				"id" => $event->getBoardId()
+			]);
+		});
+	}
 }

lib/Controller/SessionController.php

@@ -0,0 +1,88 @@
+<?php
+/**
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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\Deck\Controller;
+
+use OCA\Deck\Service\SessionService;
+use OCA\Deck\Service\PermissionService;
+use OCA\Deck\Db\BoardMapper;
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\AppFramework\ApiController;
+use OCP\IRequest;
+use OCA\Deck\Db\Acl;
+
+class SessionController extends ApiController {
+	private SessionService $sessionService;
+	private PermissionService $permissionService;
+	private BoardMapper $boardMapper;
+
+	public function __construct($appName,
+		IRequest $request,
+		SessionService $sessionService,
+		PermissionService $permissionService,
+		BoardMapper $boardMapper
+	) {
+		parent::__construct($appName, $request);
+		$this->sessionService = $sessionService;
+		$this->permissionService = $permissionService;
+		$this->boardMapper = $boardMapper;
+	}
+
+	/**
+	 * @NoAdminRequired
+	 */
+	public function create(int $boardId): DataResponse {
+		$this->permissionService->checkPermission($this->boardMapper, $boardId, Acl::PERMISSION_READ);
+
+		$session = $this->sessionService->initSession($boardId);
+		return new DataResponse([
+			'token' => $session->getToken(),
+		]);
+	}
+
+	/**
+	 * notifies the server that the session is still active
+	 * @NoAdminRequired
+	 * @param $boardId
+	 */
+	public function sync($boardId, $token): DataResponse {
+		$this->permissionService->checkPermission($this->boardMapper, $boardId, Acl::PERMISSION_READ);
+		try {
+			$this->sessionService->syncSession($boardId, $token);
+			return new DataResponse([]);
+		} catch (DoesNotExistException $e) {
+			return new DataResponse([], 403);
+		}
+	}
+
+	/**
+	 * delete a session if existing
+	 * @NoAdminRequired
+	 * @param $boardId
+	 * @return bool
+	 */
+	public function close($boardId, $token) {
+		$this->permissionService->checkPermission($this->boardMapper, $boardId, Acl::PERMISSION_READ);
+		$this->sessionService->closeSession((int)$boardId, $token);
+		return true;
+	}
+}

lib/Db/Board.php

@@ -44,6 +44,7 @@ class Board extends RelationalEntity {
 	protected $users = [];
 	protected $shared;
 	protected $stacks = [];
+	protected $activeSessions = [];
 	protected $deletedAt = 0;
 	protected $lastModified = 0;
 
@@ -59,6 +60,7 @@ class Board extends RelationalEntity {
 		$this->addRelation('acl');
 		$this->addRelation('shared');
 		$this->addRelation('users');
+		$this->addRelation('activeSessions');
 		$this->addRelation('permissions');
 		$this->addRelation('stacks');
 		$this->addRelation('settings');

lib/Db/Session.php

@@ -0,0 +1,48 @@
+<?php
+/**
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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\Deck\Db;
+
+use OCP\AppFramework\Db\Entity;
+
+class Session extends Entity implements \JsonSerializable {
+	public $id;
+	protected $userId;
+	protected $token;
+	protected $lastContact;
+	protected $boardId;
+
+	public function __construct() {
+		$this->addType('id', 'integer');
+		$this->addType('boardId', 'integer');
+		$this->addType('lastContact', 'integer');
+	}
+
+	public function jsonSerialize(): array {
+		return [
+			'id' => $this->id,
+			'userId' => $this->userId,
+			'token' => $this->token,
+			'lastContact' => $this->lastContact,
+			'boardId' => $this->boardId,
+		];
+	}
+}

lib/Db/SessionMapper.php

@@ -0,0 +1,62 @@
+<?php
+/**
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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\Deck\Db;
+
+use OCA\Deck\Service\SessionService;
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\AppFramework\Db\QBMapper;
+use OCP\IDBConnection;
+
+class SessionMapper extends QBMapper {
+	public function __construct(IDBConnection $db) {
+		parent::__construct($db, 'deck_sessions', Session::class);
+	}
+
+	public function find(int $boardId, string $userId, string $token): Session {
+		$qb = $this->db->getQueryBuilder();
+		$result = $qb->select('*')
+			->from($this->getTableName())
+			->where($qb->expr()->eq('board_id', $qb->createNamedParameter($boardId)))
+			->andWhere($qb->expr()->eq('user_id', $qb->createNamedParameter($userId)))
+			->andWhere($qb->expr()->eq('token', $qb->createNamedParameter($token)))
+			->andWhere($qb->expr()->gt('last_contact', $qb->createNamedParameter(time() - SessionService::SESSION_VALID_TIME)))
+			->executeQuery();
+
+		$data = $result->fetch();
+		$result->closeCursor();
+		if ($data === false) {
+			throw new DoesNotExistException('Session is invalid');
+		}
+		return Session::fromRow($data);
+	}
+
+	public function findAllActive($boardId) {
+		$qb = $this->db->getQueryBuilder();
+		$qb->select('id', 'board_id', 'last_contact', 'user_id')
+			->from($this->getTableName())
+			->where($qb->expr()->eq('board_id', $qb->createNamedParameter($boardId)))
+			->andWhere($qb->expr()->gt('last_contact', $qb->createNamedParameter(time() - SessionService::SESSION_VALID_TIME)))
+			->executeQuery();
+
+		return $this->findEntities($qb);
+	}
+}

lib/Event/SessionClosedEvent.php

@@ -0,0 +1,45 @@
+<?php
+/**
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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/>.
+ *
+ */
+declare(strict_types=1);
+
+
+namespace OCA\Deck\Event;
+
+use OCP\EventDispatcher\Event;
+
+class SessionClosedEvent extends Event {
+	private $boardId;
+	private $userId;
+	
+	public function __construct($boardId, $userId) {
+		parent::__construct();
+
+		$this->boardId = $boardId;
+		$this->userId = $userId;
+	}
+
+	public function getBoardId(): int {
+		return $this->boardId;
+	}
+	public function getUserId(): string {
+		return $this->userId;
+	}
+}

lib/Event/SessionCreatedEvent.php

@@ -0,0 +1,46 @@
+<?php
+/**
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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/>.
+ *
+ */
+
+declare(strict_types=1);
+
+
+namespace OCA\Deck\Event;
+
+use OCP\EventDispatcher\Event;
+
+class SessionCreatedEvent extends Event {
+	private $boardId;
+	private $userId;
+	
+	public function __construct($boardId, $userId) {
+		parent::__construct();
+
+		$this->boardId = $boardId;
+		$this->userId = $userId;
+	}
+
+	public function getBoardId(): int {
+		return $this->boardId;
+	}
+	public function getUserId(): string {
+		return $this->userId;
+	}
+}

lib/Migration/Version10900Date202206151724222.php

@@ -0,0 +1,65 @@
+<?php
+/**
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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/>.
+ *
+ */
+
+declare(strict_types=1);
+
+
+namespace OCA\Deck\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version10900Date202206151724222 extends SimpleMigrationStep {
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		$schema = $schemaClosure();
+
+		if (!$schema->hasTable('deck_sessions')) {
+			$table = $schema->createTable('deck_sessions');
+			$table->addColumn('id', 'integer', [
+				'autoincrement' => true,
+				'notnull' => true,
+				'unsigned' => true,
+			]);
+			$table->addColumn('user_id', 'string', [
+				'notnull' => false,
+				'length' => 64,
+			]);
+			$table->addColumn('board_id', 'integer', [
+				'notnull' => false,
+			]);
+			$table->addColumn('token', 'string', [
+				'notnull' => true,
+				'length' => 64,
+			]);
+			$table->addColumn('last_contact', 'integer', [
+				'notnull' => true,
+				'length' => 20,
+				'unsigned' => true,
+			]);
+			$table->setPrimaryKey(['id']);
+			$table->addIndex(['token'], 'rd_session_token_idx');
+			$table->addIndex(['last_contact'], 'ts_lastcontact');
+		}
+		return $schema;
+	}
+}

lib/Service/BoardService.php

@@ -34,6 +34,8 @@ use OCA\Deck\Db\CardMapper;
 use OCA\Deck\Db\ChangeHelper;
 use OCA\Deck\Db\IPermissionMapper;
 use OCA\Deck\Db\Label;
+use OCA\Deck\Db\Session;
+use OCA\Deck\Db\SessionMapper;
 use OCA\Deck\Db\Stack;
 use OCA\Deck\Db\StackMapper;
 use OCA\Deck\Event\AclCreatedEvent;
@@ -81,6 +83,7 @@ class BoardService {
 	private IURLGenerator $urlGenerator;
 	private IDBConnection $connection;
 	private BoardServiceValidator $boardServiceValidator;
+	private SessionMapper $sessionMapper;
 
 	public function __construct(
 		BoardMapper $boardMapper,
@@ -101,6 +104,7 @@ class BoardService {
 		IURLGenerator $urlGenerator,
 		IDBConnection $connection,
 		BoardServiceValidator $boardServiceValidator,
+		SessionMapper $sessionMapper,
 		?string $userId
 	) {
 		$this->boardMapper = $boardMapper;
@@ -122,6 +126,7 @@ class BoardService {
 		$this->urlGenerator = $urlGenerator;
 		$this->connection = $connection;
 		$this->boardServiceValidator = $boardServiceValidator;
+		$this->sessionMapper = $sessionMapper;
 	}
 
 	/**
@@ -214,6 +219,7 @@ class BoardService {
 		]);
 		$this->enrichWithUsers($board);
 		$this->enrichWithBoardSettings($board);
+		$this->enrichWithActiveSessions($board);
 		$this->boardsCache[$board->getId()] = $board;
 		return $board;
 	}
@@ -448,6 +454,14 @@ class BoardService {
 		$board->setSettings($settings);
 	}
 
+	public function enrichWithActiveSessions(Board $board) {
+		$sessions = $this->sessionMapper->findAllActive($board->getId());
+		
+		$board->setActiveSessions(array_unique(array_map(function (Session $session) {
+			return $session->getUserId();
+		}, $sessions)));
+	}
+
 	/**
 	 * @param $boardId
 	 * @param $type

lib/Service/SessionService.php

@@ -0,0 +1,95 @@
+<?php
+/**
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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\Deck\Service;
+
+use OCA\Deck\Db\Session;
+use OCA\Deck\Db\SessionMapper;
+use OCA\Deck\Event\SessionCreatedEvent;
+use OCA\Deck\Event\SessionClosedEvent;
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCA\NotifyPush\Queue\IQueue;
+use OCP\Security\ISecureRandom;
+
+class SessionService {
+	public const SESSION_VALID_TIME = 30;
+
+	private SessionMapper $sessionMapper;
+	private ITimeFactory $timeFactory;
+	private string|null $userId;
+	private IEventDispatcher $eventDispatcher;
+	private ISecureRandom $secureRandom;
+
+	public function __construct(
+		SessionMapper $sessionMapper,
+		ISecureRandom $secureRandom,
+		ITimeFactory $timeFactory,
+		$userId,
+		IEventDispatcher $eventDispatcher
+	) {
+		$this->sessionMapper = $sessionMapper;
+		$this->secureRandom = $secureRandom;
+		$this->timeFactory = $timeFactory;
+		$this->userId = $userId;
+		$this->eventDispatcher = $eventDispatcher;
+	}
+
+	public function initSession($boardId): Session {
+		$session = new Session();
+		$session->setBoardId($boardId);
+		$session->setUserId($this->userId);
+		$session->setToken($this->secureRandom->generate(64));
+		$session->setLastContact($this->timeFactory->getTime());
+
+		$session = $this->sessionMapper->insert($session);
+		$this->eventDispatcher->dispatchTyped(new SessionCreatedEvent($boardId, $this->userId));
+		return $session;
+	}
+
+	public function syncSession(int $boardId, string $token) {
+		$session = $this->sessionMapper->find($boardId, $this->userId, $token);
+		$session->setLastContact($this->timeFactory->getTime());
+		$this->sessionMapper->update($session);
+	}
+
+	public function closeSession(int $boardId, string $token): void {
+		try {
+			$session = $this->sessionMapper->find($boardId, $this->userId, $token);
+			$this->sessionMapper->delete($session);
+		} catch (DoesNotExistException $e) {
+		}
+		$this->eventDispatcher->dispatchTyped(new SessionClosedEvent($boardId, $this->userId));
+	}
+
+	public function notifyAllSessions(IQueue $queue, int $boardId, $event, $excludeUserId, $body) {
+		$activeSessions = $this->sessionMapper->findAllActive($boardId);
+
+		foreach ($activeSessions as $session) {
+			$queue->push("notify_custom", [
+				'user' => $session->getUserId(),
+				'message' => $event,
+				'body' => $body
+			]);
+		}
+	}
+}

package.json

@@ -39,6 +39,7 @@
     "@nextcloud/initial-state": "^2.0.0",
     "@nextcloud/l10n": "^1.6.0",
     "@nextcloud/moment": "^1.2.1",
+		"@nextcloud/notify_push": "^1.1.2",
     "@nextcloud/router": "^2.0.1",
     "@nextcloud/vue": "^7.3.0",
     "@nextcloud/vue-dashboard": "^2.0.1",

psalm.xml

@@ -42,6 +42,7 @@
 				<referencedClass name="OC\*" />
 				<referencedClass name="OC" />
 				<referencedClass name="OC\Security\CSP\ContentSecurityPolicyNonceManager" />
+				<referencedClass name="OCA\NotifyPush\Queue\IQueue" />
 			</errorLevel>
 		</UndefinedClass>
 		<UndefinedDocblockClass>

src/components/Controls.vue

@@ -40,6 +40,8 @@
 			</p>
 		</div>
 		<div class="board-actions">
+			<SessionList v-if="isNotifyPushEnabled && board && board.activeSessions"
+				:sessions="board.activeSessions" />
 			<div v-if="searchQuery || true" class="deck-search">
 				<input type="search"
 					class="icon-search"
@@ -224,6 +226,8 @@ import FilterIcon from 'vue-material-design-icons/Filter.vue'
 import FilterOffIcon from 'vue-material-design-icons/FilterOff.vue'
 import ArrowCollapseVerticalIcon from 'vue-material-design-icons/ArrowCollapseVertical.vue'
 import ArrowExpandVerticalIcon from 'vue-material-design-icons/ArrowExpandVertical.vue'
+import SessionList from './SessionList'
+import { isNotifyPushEnabled } from '../listeners'
 
 export default {
 	name: 'Controls',
@@ -239,6 +243,7 @@ export default {
 		FilterOffIcon,
 		ArrowCollapseVerticalIcon,
 		ArrowExpandVerticalIcon,
+		SessionList,
 	},
 	mixins: [labelStyle],
 	props: {
@@ -286,6 +291,9 @@ export default {
 		labelsSorted() {
 			return [...this.board.labels].sort((a, b) => (a.title < b.title) ? -1 : 1)
 		},
+		isNotifyPushEnabled() {
+			return isNotifyPushEnabled()
+		},
 	},
 	watch: {
 		board(current, previous) {

src/components/SessionList.vue

@@ -0,0 +1,115 @@
+<!--
+ * @copyright Copyright (c) 2019 Julius Härtl <jus@bitgrid.net>
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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/>.
+ *
+ * -->
+
+<template>
+	<div class="session-list">
+		<button slot="trigger"
+			v-tooltip.bottom="t('text', 'Active people')"
+			class="avatar-list">
+			<div v-for="session in sessionsVisible"
+				:key="session"
+				class="avatar-wrapper"
+				:style="sessionAvatarStyle">
+				<Avatar :user="session"
+					:disable-menu="true"
+					:show-user-status="false"
+					:disable-tooltip="true"
+					:size="size" />
+			</div>
+		</button>
+	</div>
+</template>
+
+<script>
+import Tooltip from '@nextcloud/vue/dist/Directives/Tooltip'
+import Avatar from '@nextcloud/vue/dist/Components/Avatar'
+
+export default {
+	name: 'SessionList',
+	components: {
+		Avatar,
+	},
+	directives: {
+		tooltip: Tooltip,
+	},
+	props: {
+		sessions: {
+			type: Array,
+			default: () => { return [] },
+		},
+		size: {
+			type: Number,
+			default: () => 32,
+		},
+	},
+	computed: {
+		sessionsVisible() {
+			if (!this.sessions) return []
+			return this.sessions.slice(0, 5)
+		},
+		sessionAvatarStyle() {
+			return {
+				'--size': this.size + 'px',
+				'--font-size': this.size / 2 + 'px',
+			}
+		},
+	},
+}
+</script>
+
+<style scoped lang="scss">
+.session-list {
+	padding-left: 0.5em;
+	padding-right: 0.5em;
+}
+.avatar-list {
+	border: none;
+	background-color: var(--color-main-background);
+	padding: 0;
+	margin: 0;
+	padding-left: 6px;
+	display: inline-flex;
+	flex-direction: row-reverse;
+
+	&:focus {
+		background-color: #eee;
+	}
+
+}
+
+.avatar-wrapper {
+	background-color: #b9b9b9;
+	border-radius: 50%;
+	border-width: 2px;
+	border-style: solid;
+	width: var(--size);
+	height: var(--size);
+	text-align: center;
+	color: #ffffff;
+	line-height: var(--size);
+	font-size: var(--font-size);
+	font-weight: normal;
+	z-index: 1;
+	overflow: hidden;
+	box-sizing: content-box !important;
+	margin-left: -8px;
+}
+</style>

src/components/board/Board.vue

@@ -81,6 +81,8 @@ import Stack from './Stack.vue'
 import { NcEmptyContent } from '@nextcloud/vue'
 import GlobalSearchResults from '../search/GlobalSearchResults.vue'
 import { showError } from '../../helpers/errors.js'
+import { sessionApi } from '../../services/SessionApi'
+import { isNotifyPushEnabled } from '../../listeners'
 
 export default {
 	name: 'Board',
@@ -128,13 +130,51 @@ export default {
 		},
 	},
 	watch: {
-		id: 'fetchData',
+		id(newValue, oldValue) {
+			if (oldValue) {
+				// close old session
+				sessionApi.closeSession(oldValue, this.token)
+				this.token = null
+			}
+			// create new session
+			this.ensureSession(newValue)
+
+			this.fetchData()
+		},
 		showArchived() {
 			this.fetchData()
 		},
 	},
 	created() {
+		if (isNotifyPushEnabled()) {
+			// create a session
+			this.ensureSession()
+		}
+
 		this.fetchData()
+
+		if (isNotifyPushEnabled()) {
+			// regularly let the server know that we are still here
+			this.sessionInterval = setInterval(() => {
+				this.ensureSession()
+			}, 25 * 1000)
+
+			// we don't get events pushed for sessions that have expired,
+			// so we poll the list of sessions every minute when there
+			// are other sessions active
+			this.refreshInterval = setInterval(() => {
+				if (this.board?.activeSessions?.length) {
+					this.refreshData()
+				}
+			}, 60 * 1000)
+		}
+	},
+	beforeDestroy() {
+		if (isNotifyPushEnabled()) {
+			sessionApi.closeSession(this.id, this.token)
+			clearInterval(this.sessionInterval)
+			clearInterval(this.refreshInterval)
+		}
 	},
 	methods: {
 		async fetchData() {
@@ -149,6 +189,32 @@ export default {
 			this.loading = false
 		},
 
+		async ensureSession(boardId = this.id) {
+			if (this.token) {
+				try {
+					await sessionApi.syncSession(boardId, this.token)
+				} catch (err) {
+					// session probably expired, let's try again
+					// with a fresh session
+					this.token = null
+					setTimeout(() => {
+						this.ensureSession()
+					}, 100)
+				}
+			} else {
+				try {
+					const res = await sessionApi.createSession(boardId)
+					this.token = res.token
+				} catch (err) {
+					showError(err)
+				}
+			}
+		},
+
+		async refreshData() {
+			await this.$store.dispatch('refreshBoard', this.id)
+		},
+
 		onDropStack({ removedIndex, addedIndex }) {
 			this.$store.dispatch('orderStack', { stack: this.stacksByBoard[removedIndex], removedIndex, addedIndex })
 		},

src/listeners.js

@@ -0,0 +1,41 @@
+/*
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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/>.
+ *
+ */
+
+import { listen } from '@nextcloud/notify_push'
+import store from './store/main'
+
+let hasPush = false
+
+/**
+ * is the notify_push app active and can
+ * provide us with real time updates?
+ */
+export function isNotifyPushEnabled() {
+	return hasPush
+}
+
+hasPush = listen('DeckBoardUpdate', (name, body) => {
+	const currentBoardId = store.state.currentBoard?.id
+
+	// only handle update event for the currently open board
+	if (body.id !== currentBoardId) return
+
+	store.dispatch('refreshBoard', currentBoardId)
+})

src/main.js

@@ -31,6 +31,7 @@ import { subscribe } from '@nextcloud/event-bus'
 import { Tooltip } from '@nextcloud/vue'
 import ClickOutside from 'vue-click-outside'
 import './models/index.js'
+import './listeners'
 
 // the server snap.js conflicts with vertical scrolling so we disable it
 document.body.setAttribute('data-snap-ignore', 'true')

src/services/SessionApi.js

@@ -0,0 +1,45 @@
+/*
+ * @copyright Copyright (c) 2022, chandi Langecker (git@chandi.it)
+ *
+ * @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/>.
+ *
+ */
+
+import axios from '@nextcloud/axios'
+import { generateUrl } from '@nextcloud/router'
+
+export class SessionApi {
+
+	url(url) {
+		url = `/apps/deck${url}`
+		return generateUrl(url)
+	}
+
+	async createSession(boardId) {
+		return (await axios.put(this.url('/session/create'), { boardId })).data
+	}
+
+	async syncSession(boardId, token) {
+		return await axios.post(this.url('/session/sync'), { boardId, token })
+	}
+
+	async closeSession(boardId, token) {
+		return await axios.post(this.url('/session/close'), { boardId, token })
+	}
+
+}
+
+export const sessionApi = new SessionApi()

tests/unit/Db/BoardTest.php

@@ -32,6 +32,7 @@ class BoardTest extends TestCase {
 			'archived' => false,
 			'users' => ['user1', 'user2'],
 			'settings' => [],
+			'activeSessions' => [],
 			'ETag' => $board->getETag(),
 		], $board->jsonSerialize());
 	}
@@ -55,6 +56,7 @@ class BoardTest extends TestCase {
 			'archived' => false,
 			'users' => ['user1', 'user2'],
 			'settings' => [],
+			'activeSessions' => [],
 			'ETag' => $board->getETag(),
 		], $board->jsonSerialize());
 	}
@@ -76,6 +78,7 @@ class BoardTest extends TestCase {
 			'archived' => false,
 			'users' => [],
 			'settings' => [],
+			'activeSessions' => [],
 			'ETag' => $board->getETag(),
 		], $board->jsonSerialize());
 	}
@@ -105,6 +108,7 @@ class BoardTest extends TestCase {
 			'shared' => 1,
 			'users' => [],
 			'settings' => [],
+			'activeSessions' => [],
 			'ETag' => $board->getETag(),
 		], $board->jsonSerialize());
 	}

tests/unit/Service/BoardServiceTest.php

@@ -34,6 +34,8 @@ use OCA\Deck\Db\BoardMapper;
 use OCA\Deck\Db\CardMapper;
 use OCA\Deck\Db\ChangeHelper;
 use OCA\Deck\Db\LabelMapper;
+use OCA\Deck\Db\Session;
+use OCA\Deck\Db\SessionMapper;
 use OCA\Deck\Db\StackMapper;
 use OCA\Deck\Event\AclCreatedEvent;
 use OCA\Deck\Event\AclDeletedEvent;
@@ -89,6 +91,8 @@ class BoardServiceTest extends TestCase {
 	private $connection;
 	/** @var BoardServiceValidator */
 	private $boardServiceValidator;
+	/** @var SessionMapper */
+	private $sessionMapper;
 
 	public function setUp(): void {
 		parent::setUp();
@@ -110,6 +114,7 @@ class BoardServiceTest extends TestCase {
 		$this->urlGenerator = $this->createMock(IURLGenerator::class);
 		$this->connection = $this->createMock(IDBConnection::class);
 		$this->boardServiceValidator = $this->createMock(BoardServiceValidator::class);
+		$this->sessionMapper = $this->createMock(SessionMapper::class);
 
 		$this->service = new BoardService(
 			$this->boardMapper,
@@ -130,6 +135,7 @@ class BoardServiceTest extends TestCase {
 			$this->urlGenerator,
 			$this->connection,
 			$this->boardServiceValidator,
+			$this->sessionMapper,
 			$this->userId
 		);
 
@@ -172,6 +178,11 @@ class BoardServiceTest extends TestCase {
 			->willReturn([
 				'admin' => 'admin',
 			]);
+		$session = $this->createMock(Session::class);
+		$this->sessionMapper->expects($this->once())
+			->method('findAllActive')
+			->with(1)
+			->willReturn([$session]);
 		$this->assertEquals($b1, $this->service->find(1));
 	}
 
@@ -224,6 +235,9 @@ class BoardServiceTest extends TestCase {
 			->willReturn([
 				'admin' => 'admin',
 			]);
+		$this->sessionMapper->expects($this->once())
+			->method('findAllActive')
+			->willReturn([]);
 		$b = $this->service->update(123, 'MyNewNameBoard', 'ffffff', false);
 
 		$this->assertEquals($b->getTitle(), 'MyNewNameBoard');
@@ -244,6 +258,10 @@ class BoardServiceTest extends TestCase {
 			->willReturn([
 				'admin' => 'admin',
 			]);
+		$this->sessionMapper->expects($this->once())
+			->method('findAllActive')
+			->with(null)
+			->willReturn([]);
 		$boardDeleted = clone $board;
 		$boardDeleted->setDeletedAt(1);
 		$this->boardMapper->expects($this->once())