Include accept / decline links in CalDAV invitation emails

Signed-off-by: Georg Ehrke <developer@georgehrke.com>

5 files changed, 566 insertions, 6 deletions

diff --git a/apps/dav/lib/BackgroundJob/CleanupInvitationTokenJob.php b/apps/dav/lib/BackgroundJob/CleanupInvitationTokenJob.php
new file mode 100644
index 00000000000..e855b57ee9f
--- /dev/null
+++ b/apps/dav/lib/BackgroundJob/CleanupInvitationTokenJob.php
@@ -0,0 +1,53 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright 2018, Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.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\BackgroundJob;
+
+use OC\BackgroundJob\TimedJob;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\IDBConnection;
+
+class CleanupInvitationTokenJob extends TimedJob {
+
+	/** @var IDBConnection  */
+	private $db;
+
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	public function __construct(IDBConnection $db, ITimeFactory $timeFactory) {
+		$this->db = $db;
+		$this->timeFactory = $timeFactory;
+
+		$this->setInterval(60 * 60 * 24);
+	}
+
+	public function run($argument) {
+		$query = $this->db->getQueryBuilder();
+		$query->delete('calendar_invitation_tokens')
+			->where($query->expr()->lt('expiration',
+				$query->createNamedParameter($this->timeFactory->getTime())))
+			->execute();
+	}
+}
diff --git a/apps/dav/lib/CalDAV/InvitationResponse/InvitationResponseServer.php b/apps/dav/lib/CalDAV/InvitationResponse/InvitationResponseServer.php
new file mode 100644
index 00000000000..61ead99ce12
--- /dev/null
+++ b/apps/dav/lib/CalDAV/InvitationResponse/InvitationResponseServer.php
@@ -0,0 +1,118 @@
+<?php
+/**
+ * @copyright Copyright (c) 2018, 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\CalDAV\InvitationResponse;
+
+use OCA\DAV\Connector\Sabre\BlockLegacyClientPlugin;
+use OCA\DAV\Connector\Sabre\CachingTree;
+use OCA\DAV\Connector\Sabre\DavAclPlugin;
+use OCA\DAV\Connector\Sabre\AnonymousOptionsPlugin;
+use OCA\DAV\RootCollection;
+use OCP\SabrePluginEvent;
+use Sabre\DAV\Auth\Plugin;
+use OCA\DAV\AppInfo\PluginManager;
+use Sabre\VObject\ITip\Message;
+
+class InvitationResponseServer {
+
+	/** @var \OCA\DAV\Connector\Sabre\Server */
+	public $server;
+
+	/**
+	 * InvitationResponseServer constructor.
+	 */
+	public function __construct() {
+		$baseUri = \OC::$WEBROOT . '/remote.php/dav/';
+		$logger = \OC::$server->getLogger();
+		$dispatcher = \OC::$server->getEventDispatcher();
+
+		$root = new RootCollection();
+		$this->server = new \OCA\DAV\Connector\Sabre\Server(new CachingTree($root));
+
+		// Add maintenance plugin
+		$this->server->addPlugin(new \OCA\DAV\Connector\Sabre\MaintenancePlugin(\OC::$server->getConfig()));
+
+		// Set URL explicitly due to reverse-proxy situations
+		$this->server->httpRequest->setUrl($baseUri);
+		$this->server->setBaseUri($baseUri);
+
+		$this->server->addPlugin(new BlockLegacyClientPlugin(\OC::$server->getConfig()));
+		$this->server->addPlugin(new AnonymousOptionsPlugin());
+		$this->server->addPlugin(new class() extends Plugin {
+			public function getCurrentPrincipal() {
+				return 'principals/system/public';
+			}
+		});
+
+		// allow setup of additional auth backends
+		$event = new SabrePluginEvent($this->server);
+		$dispatcher->dispatch('OCA\DAV\Connector\Sabre::authInit', $event);
+
+		$this->server->addPlugin(new \OCA\DAV\Connector\Sabre\ExceptionLoggerPlugin('webdav', $logger));
+		$this->server->addPlugin(new \OCA\DAV\Connector\Sabre\LockPlugin());
+		$this->server->addPlugin(new \Sabre\DAV\Sync\Plugin());
+
+		// acl
+		$acl = new DavAclPlugin();
+		$acl->principalCollectionSet = [
+			'principals/users', 'principals/groups'
+		];
+		$acl->defaultUsernamePath = 'principals/users';
+		$this->server->addPlugin($acl);
+
+		// calendar plugins
+		$this->server->addPlugin(new \OCA\DAV\CalDAV\Plugin());
+		$this->server->addPlugin(new \Sabre\CalDAV\ICSExportPlugin());
+		$this->server->addPlugin(new \OCA\DAV\CalDAV\Schedule\Plugin());
+		$this->server->addPlugin(new \Sabre\CalDAV\Subscriptions\Plugin());
+		$this->server->addPlugin(new \Sabre\CalDAV\Notifications\Plugin());
+		//$this->server->addPlugin(new \OCA\DAV\DAV\Sharing\Plugin($authBackend, \OC::$server->getRequest()));
+		$this->server->addPlugin(new \OCA\DAV\CalDAV\Publishing\PublishPlugin(
+			\OC::$server->getConfig(),
+			\OC::$server->getURLGenerator()
+		));
+
+		// wait with registering these until auth is handled and the filesystem is setup
+		$this->server->on('beforeMethod', function () use ($root) {
+			// register plugins from apps
+			$pluginManager = new PluginManager(
+				\OC::$server,
+				\OC::$server->getAppManager()
+			);
+			foreach ($pluginManager->getAppPlugins() as $appPlugin) {
+				$this->server->addPlugin($appPlugin);
+			}
+			foreach ($pluginManager->getAppCollections() as $appCollection) {
+				$root->addChild($appCollection);
+			}
+		});
+	}
+
+	/**
+	 * @param Message $iTipMessage
+	 * @return void
+	 */
+	public function handleITipMessage(Message $iTipMessage) {
+		/** @var \OCA\DAV\CalDAV\Schedule\Plugin $schedulingPlugin */
+		$schedulingPlugin = $this->server->getPlugin('caldav-schedule');
+		$schedulingPlugin->scheduleLocalDelivery($iTipMessage);
+	}
+}
\ No newline at end of file
diff --git a/apps/dav/lib/CalDAV/Schedule/IMipPlugin.php b/apps/dav/lib/CalDAV/Schedule/IMipPlugin.php
index 85973a8be12..40b4ee355f3 100644
--- a/apps/dav/lib/CalDAV/Schedule/IMipPlugin.php
+++ b/apps/dav/lib/CalDAV/Schedule/IMipPlugin.php
@@ -28,12 +28,14 @@ namespace OCA\DAV\CalDAV\Schedule;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\Defaults;
 use OCP\IConfig;
+use OCP\IDBConnection;
 use OCP\IL10N;
 use OCP\ILogger;
 use OCP\IURLGenerator;
 use OCP\L10N\IFactory as L10NFactory;
 use OCP\Mail\IEMailTemplate;
 use OCP\Mail\IMailer;
+use OCP\Security\ISecureRandom;
 use Sabre\CalDAV\Schedule\IMipPlugin as SabreIMipPlugin;
 use Sabre\VObject\Component\VCalendar;
 use Sabre\VObject\Component\VEvent;
@@ -79,6 +81,12 @@ class IMipPlugin extends SabreIMipPlugin {
 	/** @var IURLGenerator */
 	private $urlGenerator;
 
+	/** @var ISecureRandom */
+	private $random;
+
+	/** @var IDBConnection */
+	private $db;
+
 	/** @var Defaults */
 	private $defaults;
 
@@ -96,9 +104,14 @@ class IMipPlugin extends SabreIMipPlugin {
 	 * @param L10NFactory $l10nFactory
 	 * @param IUrlGenerator $urlGenerator
 	 * @param Defaults $defaults
+	 * @param ISecureRandom $random
+	 * @param IDBConnection $db
 	 * @param string $userId
 	 */
-	public function __construct(IConfig $config, IMailer $mailer, ILogger $logger, ITimeFactory $timeFactory, L10NFactory $l10nFactory, IURLGenerator $urlGenerator, Defaults $defaults, $userId) {
+	public function __construct(IConfig $config, IMailer $mailer, ILogger $logger,
+								ITimeFactory $timeFactory, L10NFactory $l10nFactory,
+								IURLGenerator $urlGenerator, Defaults $defaults,
+								ISecureRandom $random, IDBConnection $db, $userId) {
 		parent::__construct('');
 		$this->userId = $userId;
 		$this->config = $config;
@@ -107,6 +120,8 @@ class IMipPlugin extends SabreIMipPlugin {
 		$this->timeFactory = $timeFactory;
 		$this->l10nFactory = $l10nFactory;
 		$this->urlGenerator = $urlGenerator;
+		$this->random = $random;
+		$this->db = $db;
 		$this->defaults = $defaults;
 	}
 
@@ -138,7 +153,9 @@ class IMipPlugin extends SabreIMipPlugin {
 		}
 
 		// don't send out mails for events that already took place
-		if ($this->isEventInThePast($iTipMessage->message)) {
+		$lastOccurrence = $this->getLastOccurrence($iTipMessage->message);
+		$currentTime = $this->timeFactory->getTime();
+		if ($lastOccurrence < $currentTime) {
 			return;
 		}
 
@@ -222,6 +239,7 @@ class IMipPlugin extends SabreIMipPlugin {
 			$meetingAttendeeName, $meetingInviteeName);
 		$this->addBulletList($template, $l10n, $meetingWhen, $meetingLocation,
 			$meetingDescription, $meetingUrl);
+		$this->addResponseButtons($template, $l10n, $iTipMessage, $lastOccurrence);
 
 		$template->addFooter();
 		$message->useTemplate($template);
@@ -249,9 +267,9 @@ class IMipPlugin extends SabreIMipPlugin {
 	/**
 	 * check if event took place in the past already
 	 * @param VCalendar $vObject
-	 * @return bool
+	 * @return int
 	 */
-	private function isEventInThePast(VCalendar $vObject) {
+	private function getLastOccurrence(VCalendar $vObject) {
 		/** @var VEvent $component */
 		$component = $vObject->VEVENT;
 
@@ -291,8 +309,7 @@ class IMipPlugin extends SabreIMipPlugin {
 			}
 		}
 
-		$currentTime = $this->timeFactory->getTime();
-		return $lastOccurrence < $currentTime;
+		return $lastOccurrence;
 	}
 
 
@@ -460,6 +477,38 @@ class IMipPlugin extends SabreIMipPlugin {
 	}
 
 	/**
+	 * @param IEMailTemplate $template
+	 * @param IL10N $l10n
+	 * @param Message $iTipMessage
+	 * @param int $lastOccurrence
+	 */
+	private function addResponseButtons(IEMailTemplate $template, IL10N $l10n,
+										Message $iTipMessage, $lastOccurrence) {
+		$token = $this->createInvitationToken($iTipMessage, $lastOccurrence);
+
+		$template->addBodyButtonGroup(
+			$l10n->t('Accept'),
+			$this->urlGenerator->linkToRouteAbsolute('dav.invitation_response.accept', [
+				'token' => $token,
+			]),
+			$l10n->t('Decline'),
+			$this->urlGenerator->linkToRouteAbsolute('dav.invitation_response.decline', [
+				'token' => $token,
+			])
+		);
+
+		$moreOptionsURL = $this->urlGenerator->linkToRouteAbsolute('dav.invitation_response.options', [
+			'token' => $token,
+		]);
+		$html = vsprintf('<small><a href="%s">%s</a></small>', [
+			$moreOptionsURL, $l10n->t('More options ...')
+		]);
+		$text = $l10n->t('More options at %s', [$moreOptionsURL]);
+		
+		$template->addBodyText($html, $text);
+	}
+
+	/**
 	 * @param string $path
 	 * @return string
 	 */
@@ -468,4 +517,37 @@ class IMipPlugin extends SabreIMipPlugin {
 			$this->urlGenerator->imagePath('core', $path)
 		);
 	}
+
+	/**
+	 * @param Message $iTipMessage
+	 * @param int $lastOccurrence
+	 * @return string
+	 */
+	private function createInvitationToken(Message $iTipMessage, $lastOccurrence):string {
+		$token = $this->random->generate(60, ISecureRandom::CHAR_UPPER . ISecureRandom::CHAR_LOWER . ISecureRandom::CHAR_DIGITS);
+
+		/** @var VEvent $vevent */
+		$vevent = $iTipMessage->message->VEVENT;
+		$attendee = $iTipMessage->recipient;
+		$organizer = $iTipMessage->sender;
+		$sequence = $iTipMessage->sequence;
+		$recurrenceId = isset($vevent->{'RECURRENCE-ID'}) ?
+			$vevent->{'RECURRENCE-ID'}->serialize() : null;
+		$uid = $vevent->{'UID'};
+
+		$query = $this->db->getQueryBuilder();
+		$query->insert('calendar_invitation_tokens')
+			->values([
+				'token' => $query->createNamedParameter($token),
+				'attendee' => $query->createNamedParameter($attendee),
+				'organizer' => $query->createNamedParameter($organizer),
+				'sequence' => $query->createNamedParameter($sequence),
+				'recurrenceid' => $query->createNamedParameter($recurrenceId),
+				'expiration' => $query->createNamedParameter($lastOccurrence),
+				'uid' => $query->createNamedParameter($uid)
+			])
+			->execute();
+
+		return $token;
+	}
 }
diff --git a/apps/dav/lib/Controller/InvitationResponseController.php b/apps/dav/lib/Controller/InvitationResponseController.php
new file mode 100644
index 00000000000..08298a29f0f
--- /dev/null
+++ b/apps/dav/lib/Controller/InvitationResponseController.php
@@ -0,0 +1,236 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright 2018, Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.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\Controller;
+
+use OCA\DAV\CalDAV\InvitationResponse\InvitationResponseServer;
+use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http\TemplateResponse;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\IDBConnection;
+use OCP\IRequest;
+use Sabre\VObject\ITip\Message;
+use Sabre\VObject\Reader;
+
+class InvitationResponseController extends Controller {
+
+	/** @var IDBConnection */
+	private $db;
+
+	/** @var ITimeFactory */
+	private $timeFactory;
+
+	/** @var InvitationResponseServer */
+	private $responseServer;
+
+	/**
+	 * InvitationResponseController constructor.
+	 *
+	 * @param string $appName
+	 * @param IRequest $request
+	 * @param IDBConnection $db
+	 * @param ITimeFactory $timeFactory
+	 * @param InvitationResponseServer $responseServer
+	 */
+	public function __construct(string $appName, IRequest $request,
+								IDBConnection $db, ITimeFactory $timeFactory,
+								InvitationResponseServer $responseServer) {
+		parent::__construct($appName, $request);
+		$this->db = $db;
+		$this->timeFactory = $timeFactory;
+		$this->responseServer = $responseServer;
+		// Don't run `$server->exec()`, because we just need access to the
+		// fully initialized schedule plugin, but we don't want Sabre/DAV
+		// to actually handle and reply to the request
+	}
+
+	/**
+	 * @PublicPage
+	 * @NoCSRFRequired
+	 *
+	 * @param string $token
+	 * @return TemplateResponse
+	 */
+	public function accept(string $token):TemplateResponse {
+		$row = $this->getTokenInformation($token);
+		if (!$row) {
+			return new TemplateResponse($this->appName, 'schedule-response-error', [], 'guest');
+		}
+
+		$iTipMessage = $this->buildITipResponse($row, 'ACCEPTED');
+		$this->responseServer->handleITipMessage($iTipMessage);
+		if ($iTipMessage->getScheduleStatus() === '1.2') {
+			return new TemplateResponse($this->appName, 'schedule-response-success', [], 'guest');
+		}
+
+		return new TemplateResponse($this->appName, 'schedule-response-error', [
+			'organizer' => $row['organizer'],
+		], 'guest');
+	}
+
+	/**
+	 * @PublicPage
+	 * @NoCSRFRequired
+	 *
+	 * @param string $token
+	 * @return TemplateResponse
+	 */
+	public function decline(string $token):TemplateResponse {
+		$row = $this->getTokenInformation($token);
+		if (!$row) {
+			return new TemplateResponse($this->appName, 'schedule-response-error', [], 'guest');
+		}
+
+		$iTipMessage = $this->buildITipResponse($row, 'DECLINED');
+		$this->responseServer->handleITipMessage($iTipMessage);
+
+		if ($iTipMessage->getScheduleStatus() === '1.2') {
+			return new TemplateResponse($this->appName, 'schedule-response-success', [], 'guest');
+		}
+
+		return new TemplateResponse($this->appName, 'schedule-response-error', [
+			'organizer' => $row['organizer'],
+		], 'guest');
+	}
+
+	/**
+	 * @PublicPage
+	 * @NoCSRFRequired
+	 *
+	 * @param string $token
+	 * @return TemplateResponse
+	 */
+	public function options(string $token):TemplateResponse {
+		return new TemplateResponse($this->appName, 'schedule-response-options', [
+			'token' => $token
+		], 'guest');
+	}
+
+	/**
+	 * @PublicPage
+	 * @NoCSRFRequired
+	 *
+	 * @param string $token
+	 *
+	 * @return TemplateResponse
+	 */
+	public function processMoreOptionsResult(string $token):TemplateResponse {
+		$partstat = $this->request->getParam('partStat');
+		$guests = (int) $this->request->getParam('guests');
+		$comment = $this->request->getParam('comment');
+
+		$row = $this->getTokenInformation($token);
+		if (!$row || !\in_array($partstat, ['ACCEPTED', 'DECLINED', 'TENTATIVE'])) {
+			return new TemplateResponse($this->appName, 'schedule-response-error', [], 'guest');
+		}
+
+		$iTipMessage = $this->buildITipResponse($row, $partstat, $guests, $comment);
+		$this->responseServer->handleITipMessage($iTipMessage);
+		if ($iTipMessage->getScheduleStatus() === '1.2') {
+			return new TemplateResponse($this->appName, 'schedule-response-success', [], 'guest');
+		}
+
+		return new TemplateResponse($this->appName, 'schedule-response-error', [
+			'organizer' => $row['organizer'],
+		], 'guest');
+	}
+
+	/**
+	 * @param string $token
+	 * @return array|null
+	 */
+	private function getTokenInformation(string $token) {
+		$query = $this->db->getQueryBuilder();
+		$query->select('*')
+			->from('calendar_invitation_tokens')
+			->where($query->expr()->eq('token', $query->createNamedParameter($token)));
+		$stmt = $query->execute();
+		$row = $stmt->fetch(\PDO::FETCH_ASSOC);
+
+		if(!$row) {
+			return null;
+		}
+
+		$currentTime = $this->timeFactory->getTime();
+		if (((int) $row['expiration']) < $currentTime) {
+			return null;
+		}
+
+		return $row;
+	}
+
+	/**
+	 * @param array $row
+	 * @param string $partStat participation status of attendee - SEE RFC 5545
+	 * @param int|null $guests
+	 * @param string|null $comment
+	 * @return Message
+	 */
+	private function buildITipResponse(array $row, string $partStat, int $guests=null,
+									   string $comment=null):Message {
+		$iTipMessage = new Message();
+		$iTipMessage->uid = $row['uid'];
+		$iTipMessage->component = 'VEVENT';
+		$iTipMessage->method = 'REPLY';
+		$iTipMessage->sequence = $row['sequence'];
+		$iTipMessage->sender = $row['attendee'];
+		$iTipMessage->recipient = $row['organizer'];
+
+		$message = <<<EOF
+BEGIN:VCALENDAR
+PRODID:-//Nextcloud/Nextcloud CalDAV Server//EN
+METHOD:REPLY
+VERSION:2.0
+BEGIN:VEVENT
+ATTENDEE;PARTSTAT=%s:%s
+ORGANIZER:%s
+UID:%s
+SEQUENCE:%s
+REQUEST-STATUS:2.0;Success
+%sEND:VEVENT
+END:VCALENDAR
+EOF;
+
+		$vObject = Reader::read(vsprintf($message, [
+			$partStat, $row['attendee'], $row['organizer'],
+			$row['uid'], $row['sequence'] ?? 0, $row['recurrenceid'] ?? ''
+		]));
+		$vEvent = $vObject->{'VEVENT'};
+		/** @var \Sabre\VObject\Property\ICalendar\CalAddress $attendee */
+		$attendee = $vEvent->{'ATTENDEE'};
+
+		$vEvent->DTSTAMP = date('Ymd\\THis\\Z', $this->timeFactory->getTime());
+
+		if ($comment) {
+			$attendee->add('X-RESPONSE-COMMENT', $comment);
+			$vEvent->add('COMMENT', $comment);
+		}
+		if ($guests) {
+			$attendee->add('X-NUM-GUESTS', $guests);
+		}
+
+		$iTipMessage->message = $vObject;
+
+		return $iTipMessage;
+	}
+}
diff --git a/apps/dav/lib/Migration/Version1006Date20180619154313.php b/apps/dav/lib/Migration/Version1006Date20180619154313.php
new file mode 100644
index 00000000000..8fb82ffed67
--- /dev/null
+++ b/apps/dav/lib/Migration/Version1006Date20180619154313.php
@@ -0,0 +1,71 @@
+<?php
+namespace OCA\DAV\Migration;
+
+use Doctrine\DBAL\Types\Type;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\SimpleMigrationStep;
+use OCP\Migration\IOutput;
+
+/**
+ * Auto-generated migration step: Please modify to your needs!
+ */
+class Version1006Date20180619154313 extends SimpleMigrationStep {
+
+	/**
+	 * @param IOutput $output
+	 * @param \Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 * @since 13.0.0
+	 */
+	public function changeSchema(IOutput $output, \Closure $schemaClosure, array $options) {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		if (!$schema->hasTable('calendar_invitation_tokens')) {
+			$table = $schema->createTable('calendar_invitation_tokens');
+
+			$table->addColumn('id', Type::BIGINT, [
+				'autoincrement' => true,
+				'notnull' => true,
+				'length' => 11,
+				'unsigned' => true,
+			]);
+			$table->addColumn('uid', Type::STRING, [
+				'notnull' => true,
+				'length' => 255,
+			]);
+			$table->addColumn('recurrenceid', Type::STRING, [
+				'notnull' => false,
+				'length' => 255,
+			]);
+			$table->addColumn('attendee', Type::STRING, [
+				'notnull' => true,
+				'length' => 255,
+			]);
+			$table->addColumn('organizer', Type::STRING, [
+				'notnull' => true,
+				'length' => 255,
+			]);
+			$table->addColumn('sequence', Type::BIGINT, [
+				'notnull' => false,
+				'length' => 11,
+				'unsigned' => true,
+			]);
+			$table->addColumn('token', Type::STRING, [
+				'notnull' => true,
+				'length' => 60,
+			]);
+			$table->addColumn('expiration', Type::BIGINT, [
+				'notnull' => true,
+				'length' => 11,
+				'unsigned' => true,
+			]);
+
+			$table->setPrimaryKey(['id'], 'calendar_invitation_tokens_id_idx');
+			$table->addIndex(['token'], 'calendar_invitation_tokens_token_idx');
+
+			return $schema;
+		}
+	}
+}