feat: Calendar Exportfeat/issue-563-calendar-export

Signed-off-by: SebastianKrupinski <krupinskis05@gmail.com>

15 files changed, 522 insertions, 15 deletions

diff --git a/apps/dav/appinfo/info.xml b/apps/dav/appinfo/info.xml
index a99bea224b6..ac8886555f6 100644
--- a/apps/dav/appinfo/info.xml
+++ b/apps/dav/appinfo/info.xml
@@ -60,6 +60,7 @@
 		<command>OCA\DAV\Command\CreateSubscription</command>
 		<command>OCA\DAV\Command\DeleteCalendar</command>
 		<command>OCA\DAV\Command\DeleteSubscription</command>
+		<command>OCA\DAV\Command\ExportCalendar</command>
 		<command>OCA\DAV\Command\FixCalendarSyncCommand</command>
 		<command>OCA\DAV\Command\ListAddressbooks</command>
 		<command>OCA\DAV\Command\ListCalendars</command>
diff --git a/apps/dav/composer/composer/autoload_classmap.php b/apps/dav/composer/composer/autoload_classmap.php
index 0e0ae51bb7a..94626cce752 100644
--- a/apps/dav/composer/composer/autoload_classmap.php
+++ b/apps/dav/composer/composer/autoload_classmap.php
@@ -64,6 +64,7 @@ return array(
     'OCA\\DAV\\CalDAV\\EventReader' => $baseDir . '/../lib/CalDAV/EventReader.php',
     'OCA\\DAV\\CalDAV\\EventReaderRDate' => $baseDir . '/../lib/CalDAV/EventReaderRDate.php',
     'OCA\\DAV\\CalDAV\\EventReaderRRule' => $baseDir . '/../lib/CalDAV/EventReaderRRule.php',
+    'OCA\\DAV\\CalDAV\\Export\\ExportService' => $baseDir . '/../lib/CalDAV/Export/ExportService.php',
     'OCA\\DAV\\CalDAV\\FreeBusy\\FreeBusyGenerator' => $baseDir . '/../lib/CalDAV/FreeBusy/FreeBusyGenerator.php',
     'OCA\\DAV\\CalDAV\\ICSExportPlugin\\ICSExportPlugin' => $baseDir . '/../lib/CalDAV/ICSExportPlugin/ICSExportPlugin.php',
     'OCA\\DAV\\CalDAV\\IRestorable' => $baseDir . '/../lib/CalDAV/IRestorable.php',
@@ -159,6 +160,7 @@ return array(
     'OCA\\DAV\\Command\\CreateSubscription' => $baseDir . '/../lib/Command/CreateSubscription.php',
     'OCA\\DAV\\Command\\DeleteCalendar' => $baseDir . '/../lib/Command/DeleteCalendar.php',
     'OCA\\DAV\\Command\\DeleteSubscription' => $baseDir . '/../lib/Command/DeleteSubscription.php',
+    'OCA\\DAV\\Command\\ExportCalendar' => $baseDir . '/../lib/Command/ExportCalendar.php',
     'OCA\\DAV\\Command\\FixCalendarSyncCommand' => $baseDir . '/../lib/Command/FixCalendarSyncCommand.php',
     'OCA\\DAV\\Command\\ListAddressbooks' => $baseDir . '/../lib/Command/ListAddressbooks.php',
     'OCA\\DAV\\Command\\ListCalendars' => $baseDir . '/../lib/Command/ListCalendars.php',
diff --git a/apps/dav/composer/composer/autoload_static.php b/apps/dav/composer/composer/autoload_static.php
index c6ac9757c5b..b30da1d48c9 100644
--- a/apps/dav/composer/composer/autoload_static.php
+++ b/apps/dav/composer/composer/autoload_static.php
@@ -79,6 +79,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\CalDAV\\EventReader' => __DIR__ . '/..' . '/../lib/CalDAV/EventReader.php',
         'OCA\\DAV\\CalDAV\\EventReaderRDate' => __DIR__ . '/..' . '/../lib/CalDAV/EventReaderRDate.php',
         'OCA\\DAV\\CalDAV\\EventReaderRRule' => __DIR__ . '/..' . '/../lib/CalDAV/EventReaderRRule.php',
+        'OCA\\DAV\\CalDAV\\Export\\ExportService' => __DIR__ . '/..' . '/../lib/CalDAV/Export/ExportService.php',
         'OCA\\DAV\\CalDAV\\FreeBusy\\FreeBusyGenerator' => __DIR__ . '/..' . '/../lib/CalDAV/FreeBusy/FreeBusyGenerator.php',
         'OCA\\DAV\\CalDAV\\ICSExportPlugin\\ICSExportPlugin' => __DIR__ . '/..' . '/../lib/CalDAV/ICSExportPlugin/ICSExportPlugin.php',
         'OCA\\DAV\\CalDAV\\IRestorable' => __DIR__ . '/..' . '/../lib/CalDAV/IRestorable.php',
@@ -174,6 +175,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Command\\CreateSubscription' => __DIR__ . '/..' . '/../lib/Command/CreateSubscription.php',
         'OCA\\DAV\\Command\\DeleteCalendar' => __DIR__ . '/..' . '/../lib/Command/DeleteCalendar.php',
         'OCA\\DAV\\Command\\DeleteSubscription' => __DIR__ . '/..' . '/../lib/Command/DeleteSubscription.php',
+        'OCA\\DAV\\Command\\ExportCalendar' => __DIR__ . '/..' . '/../lib/Command/ExportCalendar.php',
         'OCA\\DAV\\Command\\FixCalendarSyncCommand' => __DIR__ . '/..' . '/../lib/Command/FixCalendarSyncCommand.php',
         'OCA\\DAV\\Command\\ListAddressbooks' => __DIR__ . '/..' . '/../lib/Command/ListAddressbooks.php',
         'OCA\\DAV\\Command\\ListCalendars' => __DIR__ . '/..' . '/../lib/Command/ListCalendars.php',
diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index 2ef57ca77bb..e69fe9ed3f0 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -9,6 +9,7 @@ namespace OCA\DAV\CalDAV;
 use DateTime;
 use DateTimeImmutable;
 use DateTimeInterface;
+use Generator;
 use OCA\DAV\AppInfo\Application;
 use OCA\DAV\CalDAV\Sharing\Backend;
 use OCA\DAV\Connector\Sabre\Principal;
@@ -28,6 +29,7 @@ use OCA\DAV\Events\SubscriptionCreatedEvent;
 use OCA\DAV\Events\SubscriptionDeletedEvent;
 use OCA\DAV\Events\SubscriptionUpdatedEvent;
 use OCP\AppFramework\Db\TTransactional;
+use OCP\Calendar\CalendarExportOptions;
 use OCP\Calendar\Events\CalendarObjectCreatedEvent;
 use OCP\Calendar\Events\CalendarObjectDeletedEvent;
 use OCP\Calendar\Events\CalendarObjectMovedEvent;
@@ -988,6 +990,44 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	}
 
 	/**
+	 * Returns all calendar entries as a stream of data
+	 *
+	 * @since 32.0.0
+	 *
+	 * @return Generator<array>
+	 */
+	public function exportCalendar(int $calendarId, int $calendarType = self::CALENDAR_TYPE_CALENDAR, ?CalendarExportOptions $options = null): Generator {
+		// extract options
+		$rangeStart = $options?->getRangeStart();
+		$rangeCount = $options?->getRangeCount();
+		// construct query
+		$qb = $this->db->getQueryBuilder();
+		$qb->select('*')
+			->from('calendarobjects')
+			->where($qb->expr()->eq('calendarid', $qb->createNamedParameter($calendarId)))
+			->andWhere($qb->expr()->eq('calendartype', $qb->createNamedParameter($calendarType)))
+			->andWhere($qb->expr()->isNull('deleted_at'));
+		if ($rangeStart !== null) {
+			$qb->andWhere($qb->expr()->gt('uid', $qb->createNamedParameter($rangeStart)));
+		}
+		if ($rangeCount !== null) {
+			$qb->setMaxResults($rangeCount);
+		}
+		if ($rangeStart !== null || $rangeCount !== null) {
+			$qb->orderBy('uid', 'ASC');
+		}
+		$rs = $qb->executeQuery();
+		// iterate through results
+		try {
+			while (($row = $rs->fetch()) !== false) {
+				yield $row;
+			}
+		} finally {
+			$rs->closeCursor();
+		}
+	}
+	
+	/**
 	 * Returns all calendar objects with limited metadata for a calendar
 	 *
 	 * Every item contains an array with the following keys:
diff --git a/apps/dav/lib/CalDAV/CalendarImpl.php b/apps/dav/lib/CalDAV/CalendarImpl.php
index b3062f005ee..46f1b9aef9d 100644
--- a/apps/dav/lib/CalDAV/CalendarImpl.php
+++ b/apps/dav/lib/CalDAV/CalendarImpl.php
@@ -8,9 +8,14 @@ declare(strict_types=1);
  */
 namespace OCA\DAV\CalDAV;
 
+use Generator;
 use OCA\DAV\CalDAV\Auth\CustomPrincipalPlugin;
 use OCA\DAV\CalDAV\InvitationResponse\InvitationResponseServer;
+use OCP\Calendar\CalendarExportOptions;
 use OCP\Calendar\Exceptions\CalendarException;
+use OCP\Calendar\ICalendarExport;
+use OCP\Calendar\ICalendarIsShared;
+use OCP\Calendar\ICalendarIsWritable;
 use OCP\Calendar\ICreateFromString;
 use OCP\Calendar\IHandleImipMessage;
 use OCP\Constants;
@@ -24,7 +29,7 @@ use Sabre\VObject\Property;
 use Sabre\VObject\Reader;
 use function Sabre\Uri\split as uriSplit;
 
-class CalendarImpl implements ICreateFromString, IHandleImipMessage {
+class CalendarImpl implements ICreateFromString, IHandleImipMessage, ICalendarIsWritable, ICalendarIsShared, ICalendarExport {
 	public function __construct(
 		private Calendar $calendar,
 		/** @var array<string, mixed> */
@@ -257,4 +262,27 @@ class CalendarImpl implements ICreateFromString, IHandleImipMessage {
 	public function getInvitationResponseServer(): InvitationResponseServer {
 		return new InvitationResponseServer(false);
 	}
+
+	/**
+	 * Export objects
+	 *
+	 * @since 32.0.0
+	 *
+	 * @return Generator<mixed, \Sabre\VObject\Component\VCalendar, mixed, mixed>
+	 */
+	public function export(?CalendarExportOptions $options = null): Generator {
+		foreach (
+			$this->backend->exportCalendar(
+				$this->calendarInfo['id'],
+				$this->backend::CALENDAR_TYPE_CALENDAR,
+				$options
+			) as $event
+		) {
+			$vObject = Reader::read($event['calendardata']);
+			if ($vObject instanceof VCalendar) {
+				yield $vObject;
+			}
+		}
+	}
+
 }
diff --git a/apps/dav/lib/CalDAV/Export/ExportService.php b/apps/dav/lib/CalDAV/Export/ExportService.php
new file mode 100644
index 00000000000..393c53b92e4
--- /dev/null
+++ b/apps/dav/lib/CalDAV/Export/ExportService.php
@@ -0,0 +1,107 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\DAV\CalDAV\Export;
+
+use Generator;
+use OCP\Calendar\CalendarExportOptions;
+use OCP\Calendar\ICalendarExport;
+use OCP\ServerVersion;
+use Sabre\VObject\Component;
+use Sabre\VObject\Writer;
+
+/**
+ * Calendar Export Service
+ */
+class ExportService {
+	
+	public const FORMATS = ['ical', 'jcal', 'xcal'];
+	private string $systemVersion;
+
+	public function __construct(ServerVersion $serverVersion) {
+		$this->systemVersion = $serverVersion->getVersionString();
+	}
+
+	/**
+	 * Generates serialized content stream for a calendar and objects based in selected format
+	 *
+	 * @return Generator<string>
+	 */
+	public function export(ICalendarExport $calendar, CalendarExportOptions $options): Generator {
+		// output start of serialized content based on selected format
+		yield $this->exportStart($options->getFormat());
+		// iterate through each returned vCalendar entry
+		// extract each component except timezones, convert to appropriate format and output
+		// extract any timezones and save them but do not output
+		$timezones = [];
+		foreach ($calendar->export($options) as $entry) {
+			$consecutive = false;
+			foreach ($entry->getComponents() as $vComponent) {
+				if ($vComponent->name === 'VTIMEZONE') {
+					if (isset($vComponent->TZID) && !isset($timezones[$vComponent->TZID->getValue()])) {
+						$timezones[$vComponent->TZID->getValue()] = clone $vComponent;
+					}
+				} else {
+					yield $this->exportObject($vComponent, $options->getFormat(), $consecutive);
+					$consecutive = true;
+				}
+			}
+		}
+		// iterate through each saved vTimezone entry, convert to appropriate format and output
+		foreach ($timezones as $vComponent) {
+			yield $this->exportObject($vComponent, $options->getFormat(), $consecutive);
+			$consecutive = true;
+		}
+		// output end of serialized content based on selected format
+		yield $this->exportFinish($options->getFormat());
+	}
+
+	/**
+	 * Generates serialized content start based on selected format
+	 */
+	private function exportStart(string $format): string {
+		return match ($format) {
+			'jcal' => '["vcalendar",[["version",{},"text","2.0"],["prodid",{},"text","-\/\/IDN nextcloud.com\/\/Calendar Export v' . $this->systemVersion . '\/\/EN"]],[',
+			'xcal' => '<?xml version="1.0" encoding="UTF-8"?><icalendar xmlns="urn:ietf:params:xml:ns:icalendar-2.0"><vcalendar><properties><version><text>2.0</text></version><prodid><text>-//IDN nextcloud.com//Calendar Export v' . $this->systemVersion . '//EN</text></prodid></properties><components>',
+			default => "BEGIN:VCALENDAR\nVERSION:2.0\nPRODID:-//IDN nextcloud.com//Calendar Export v" . $this->systemVersion . "//EN\n"
+		};
+	}
+
+	/**
+	 * Generates serialized content end based on selected format
+	 */
+	private function exportFinish(string $format): string {
+		return match ($format) {
+			'jcal' => ']]',
+			'xcal' => '</components></vcalendar></icalendar>',
+			default => "END:VCALENDAR\n"
+		};
+	}
+
+	/**
+	 * Generates serialized content for a component based on selected format
+	 */
+	private function exportObject(Component $vobject, string $format, bool $consecutive): string {
+		return match ($format) {
+			'jcal' => $consecutive ? ',' . Writer::writeJson($vobject) : Writer::writeJson($vobject),
+			'xcal' => $this->exportObjectXml($vobject),
+			default => Writer::write($vobject)
+		};
+	}
+	
+	/**
+	 * Generates serialized content for a component in xml format
+	 */
+	private function exportObjectXml(Component $vobject): string {
+		$writer = new \Sabre\Xml\Writer();
+		$writer->openMemory();
+		$writer->setIndent(false);
+		$vobject->xmlSerialize($writer);
+		return $writer->outputMemory();
+	}
+
+}
diff --git a/apps/dav/lib/Command/ExportCalendar.php b/apps/dav/lib/Command/ExportCalendar.php
new file mode 100644
index 00000000000..5758cd4fa87
--- /dev/null
+++ b/apps/dav/lib/Command/ExportCalendar.php
@@ -0,0 +1,95 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\DAV\Command;
+
+use InvalidArgumentException;
+use OCA\DAV\CalDAV\Export\ExportService;
+use OCP\Calendar\CalendarExportOptions;
+use OCP\Calendar\ICalendarExport;
+use OCP\Calendar\IManager;
+use OCP\IUserManager;
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+
+/**
+ * Calendar Export Command
+ *
+ * Used to export data from supported calendars to disk or stdout
+ */
+#[AsCommand(
+	name: 'calendar:export',
+	description: 'Export calendar data from supported calendars to disk or stdout',
+	hidden: false
+)]
+class ExportCalendar extends Command {
+	public function __construct(
+		private IUserManager $userManager,
+		private IManager $calendarManager,
+		private ExportService $exportService,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('calendar:export')
+			->setDescription('Export calendar data from supported calendars to disk or stdout')
+			->addArgument('uid', InputArgument::REQUIRED, 'Id of system user')
+			->addArgument('uri', InputArgument::REQUIRED, 'Uri of calendar')
+			->addOption('format', null, InputOption::VALUE_REQUIRED, 'Format of output (ical, jcal, xcal) defaults to ical', 'ical')
+			->addOption('location', null, InputOption::VALUE_REQUIRED, 'Location of where to write the output. defaults to stdout');
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$userId = $input->getArgument('uid');
+		$calendarId = $input->getArgument('uri');
+		$format = $input->getOption('format');
+		$location = $input->getOption('location');
+
+		if (!$this->userManager->userExists($userId)) {
+			throw new InvalidArgumentException("User <$userId> not found.");
+		}
+		// retrieve calendar and evaluate if export is supported
+		$calendars = $this->calendarManager->getCalendarsForPrincipal('principals/users/' . $userId, [$calendarId]);
+		if ($calendars === []) {
+			throw new InvalidArgumentException("Calendar <$calendarId> not found.");
+		}
+		$calendar = $calendars[0];
+		if (!$calendar instanceof ICalendarExport) {
+			throw new InvalidArgumentException("Calendar <$calendarId> does not support exporting");
+		}
+		// construct options object
+		$options = new CalendarExportOptions();
+		// evaluate if provided format is supported
+		if (!in_array($format, ExportService::FORMATS, true)) {
+			throw new InvalidArgumentException("Format <$format> is not valid.");
+		}
+		$options->setFormat($format);
+		// evaluate is a valid location was given and is usable otherwise output to stdout
+		if ($location !== null) {
+			$handle = fopen($location, 'wb');
+			if ($handle === false) {
+				throw new InvalidArgumentException("Location <$location> is not valid. Can not open location for write operation.");
+			}
+			
+			foreach ($this->exportService->export($calendar, $options) as $chunk) {
+				fwrite($handle, $chunk);
+			}
+			fclose($handle);
+		} else {
+			foreach ($this->exportService->export($calendar, $options) as $chunk) {
+				$output->writeln($chunk);
+			}
+		}
+
+		return self::SUCCESS;
+	}
+}
diff --git a/apps/dav/lib/Listener/AddMissingIndicesListener.php b/apps/dav/lib/Listener/AddMissingIndicesListener.php
index 035c6c9582e..d3a1cf4b224 100644
--- a/apps/dav/lib/Listener/AddMissingIndicesListener.php
+++ b/apps/dav/lib/Listener/AddMissingIndicesListener.php
@@ -30,6 +30,11 @@ class AddMissingIndicesListener implements IEventListener {
 			'dav_shares_resourceid_access',
 			['resourceid', 'access']
 		);
+		$event->addMissingIndex(
+			'calendarobjects',
+			'calobjects_by_uid_index',
+			['calendarid', 'calendartype', 'uid']
+		);
 	}
 
 }
diff --git a/apps/dav/lib/Migration/Version1006Date20180628111625.php b/apps/dav/lib/Migration/Version1006Date20180628111625.php
index 5f3aa4b6fe2..f4be26e6ad0 100644
--- a/apps/dav/lib/Migration/Version1006Date20180628111625.php
+++ b/apps/dav/lib/Migration/Version1006Date20180628111625.php
@@ -49,6 +49,7 @@ class Version1006Date20180628111625 extends SimpleMigrationStep {
 				$calendarObjectsTable->dropIndex('calobjects_index');
 			}
 			$calendarObjectsTable->addUniqueIndex(['calendarid', 'calendartype', 'uri'], 'calobjects_index');
+			$calendarObjectsTable->addUniqueIndex(['calendarid', 'calendartype', 'uid'], 'calobjects_by_uid_index');
 		}
 
 		if ($schema->hasTable('calendarobjects_props')) {
diff --git a/apps/dav/tests/unit/CalDAV/CalendarImplTest.php b/apps/dav/tests/unit/CalDAV/CalendarImplTest.php
index ee9b85fafe8..0d5223739f3 100644
--- a/apps/dav/tests/unit/CalDAV/CalendarImplTest.php
+++ b/apps/dav/tests/unit/CalDAV/CalendarImplTest.php
@@ -5,6 +5,7 @@
  */
 namespace OCA\DAV\Tests\unit\CalDAV;
 
+use Generator;
 use OCA\DAV\CalDAV\Auth\CustomPrincipalPlugin;
 use OCA\DAV\CalDAV\CalDavBackend;
 use OCA\DAV\CalDAV\Calendar;
@@ -20,24 +21,19 @@ use Sabre\VObject\ITip\Message;
 use Sabre\VObject\Reader;
 
 class CalendarImplTest extends \Test\TestCase {
-	/** @var CalendarImpl */
-	private $calendarImpl;
 
-	/** @var Calendar | \PHPUnit\Framework\MockObject\MockObject */
-	private $calendar;
-
-	/** @var array */
-	private $calendarInfo;
-
-	/** @var CalDavBackend | \PHPUnit\Framework\MockObject\MockObject */
-	private $backend;
+	private Calendar|MockObject $calendar;
+	private array $calendarInfo;
+	private CalDavBackend|MockObject $backend;
+	private CalendarImpl|MockObject $calendarImpl;
+	private array $mockExportCollection;
 
 	protected function setUp(): void {
 		parent::setUp();
 
 		$this->calendar = $this->createMock(Calendar::class);
 		$this->calendarInfo = [
-			'id' => 'fancy_id_123',
+			'id' => 1,
 			'{DAV:}displayname' => 'user readable name 123',
 			'{http://apple.com/ns/ical/}calendar-color' => '#AABBCC',
 			'uri' => '/this/is/a/uri',
@@ -45,13 +41,16 @@ class CalendarImplTest extends \Test\TestCase {
 		];
 		$this->backend = $this->createMock(CalDavBackend::class);
 
-		$this->calendarImpl = new CalendarImpl($this->calendar,
-			$this->calendarInfo, $this->backend);
+		$this->calendarImpl = new CalendarImpl(
+			$this->calendar,
+			$this->calendarInfo,
+			$this->backend
+		);
 	}
 
 
 	public function testGetKey(): void {
-		$this->assertEquals($this->calendarImpl->getKey(), 'fancy_id_123');
+		$this->assertEquals($this->calendarImpl->getKey(), 1);
 	}
 
 	public function testGetDisplayname(): void {
@@ -261,4 +260,48 @@ EOF;
 		$iTipMessage->message = $vObject;
 		return $iTipMessage;
 	}
+
+	protected function mockExportGenerator(): Generator {
+		foreach ($this->mockExportCollection as $entry) {
+			yield $entry;
+		}
+	}
+
+	public function testExport(): void {
+		// Arrange
+		// construct calendar with a 1 hour event and same start/end time zones
+		$vCalendar = new VCalendar();
+		/** @var VEvent $vEvent */
+		$vEvent = $vCalendar->add('VEVENT', []);
+		$vEvent->UID->setValue('96a0e6b1-d886-4a55-a60d-152b31401dcc');
+		$vEvent->add('DTSTART', '20240701T080000', ['TZID' => 'America/Toronto']);
+		$vEvent->add('DTEND', '20240701T090000', ['TZID' => 'America/Toronto']);
+		$vEvent->add('SUMMARY', 'Test Recurrence Event');
+		$vEvent->add('ORGANIZER', 'mailto:organizer@testing.com', ['CN' => 'Organizer']);
+		$vEvent->add('ATTENDEE', 'mailto:attendee1@testing.com', [
+			'CN' => 'Attendee One',
+			'CUTYPE' => 'INDIVIDUAL',
+			'PARTSTAT' => 'NEEDS-ACTION',
+			'ROLE' => 'REQ-PARTICIPANT',
+			'RSVP' => 'TRUE'
+		]);
+		// construct data store return
+		$this->mockExportCollection[] = [
+			'id' => 1,
+			'calendardata' => $vCalendar->serialize()
+		];
+		$this->backend->expects($this->once())
+			->method('exportCalendar')
+			->with(1, $this->backend::CALENDAR_TYPE_CALENDAR, null)
+			->willReturn($this->mockExportGenerator());
+
+		// Act
+		foreach ($this->calendarImpl->export(null) as $entry) {
+			$exported[] = $entry;
+		}
+		
+		// Assert
+		$this->assertCount(1, $exported, 'Invalid exported items count');
+	}
+
 }
diff --git a/apps/dav/tests/unit/CalDAV/Export/ExportServiceTest.php b/apps/dav/tests/unit/CalDAV/Export/ExportServiceTest.php
new file mode 100644
index 00000000000..f1e049c4a80
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/Export/ExportServiceTest.php
@@ -0,0 +1,80 @@
+<?php
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\DAV\Tests\unit\CalDAV\Export;
+
+use Generator;
+use OCA\DAV\CalDAV\Export\ExportService;
+use OCP\Calendar\CalendarExportOptions;
+use OCP\Calendar\ICalendarExport;
+use OCP\ServerVersion;
+use PHPUnit\Framework\MockObject\MockObject;
+use Sabre\VObject\Component\VCalendar;
+
+class ExportServiceTest extends \Test\TestCase {
+
+	private ServerVersion|MockObject $serverVersion;
+	private ExportService $service;
+	private ICalendarExport|MockObject $calendar;
+	private array $mockExportCollection;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->serverVersion = $this->createMock(ServerVersion::class);
+		$this->serverVersion->method('getVersionString')
+			->willReturn('32.0.0.0');
+		$this->service = new ExportService($this->serverVersion);
+		$this->calendar = $this->createMock(ICalendarExport::class);
+
+	}
+
+	protected function mockGenerator(): Generator {
+		foreach ($this->mockExportCollection as $entry) {
+			yield $entry;
+		}
+	}
+	
+	public function testExport(): void {
+		// Arrange
+		// construct calendar with a 1 hour event and same start/end time zones
+		$vCalendar = new VCalendar();
+		/** @var \Sabre\VObject\Component\VEvent $vEvent */
+		$vEvent = $vCalendar->add('VEVENT', []);
+		$vEvent->UID->setValue('96a0e6b1-d886-4a55-a60d-152b31401dcc');
+		$vEvent->add('DTSTART', '20240701T080000', ['TZID' => 'America/Toronto']);
+		$vEvent->add('DTEND', '20240701T090000', ['TZID' => 'America/Toronto']);
+		$vEvent->add('SUMMARY', 'Test Recurrence Event');
+		$vEvent->add('ORGANIZER', 'mailto:organizer@testing.com', ['CN' => 'Organizer']);
+		$vEvent->add('ATTENDEE', 'mailto:attendee1@testing.com', [
+			'CN' => 'Attendee One',
+			'CUTYPE' => 'INDIVIDUAL',
+			'PARTSTAT' => 'NEEDS-ACTION',
+			'ROLE' => 'REQ-PARTICIPANT',
+			'RSVP' => 'TRUE'
+		]);
+		// construct calendar return
+		$options = new CalendarExportOptions();
+		$this->mockExportCollection[] = $vCalendar;
+		$this->calendar->expects($this->once())
+			->method('export')
+			->with($options)
+			->willReturn($this->mockGenerator());
+
+		// Act
+		$document = '';
+		foreach ($this->service->export($this->calendar, $options) as $chunk) {
+			$document .= $chunk;
+		}
+
+		// Assert
+		$this->assertStringContainsString('BEGIN:VCALENDAR', $document, 'Exported document calendar start missing');
+		$this->assertStringContainsString('BEGIN:VEVENT', $document, 'Exported document event start missing');
+		$this->assertStringContainsString('END:VEVENT', $document, 'Exported document event end missing');
+		$this->assertStringContainsString('END:VCALENDAR', $document, 'Exported document calendar end missing');
+
+	}
+
+}
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index 6264126b028..177abfefe8e 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -191,6 +191,7 @@ return array(
     'OCP\\Cache\\CappedMemoryCache' => $baseDir . '/lib/public/Cache/CappedMemoryCache.php',
     'OCP\\Calendar\\BackendTemporarilyUnavailableException' => $baseDir . '/lib/public/Calendar/BackendTemporarilyUnavailableException.php',
     'OCP\\Calendar\\CalendarEventStatus' => $baseDir . '/lib/public/Calendar/CalendarEventStatus.php',
+    'OCP\\Calendar\\CalendarExportOptions' => $baseDir . '/lib/public/Calendar/CalendarExportOptions.php',
     'OCP\\Calendar\\Events\\AbstractCalendarObjectEvent' => $baseDir . '/lib/public/Calendar/Events/AbstractCalendarObjectEvent.php',
     'OCP\\Calendar\\Events\\CalendarObjectCreatedEvent' => $baseDir . '/lib/public/Calendar/Events/CalendarObjectCreatedEvent.php',
     'OCP\\Calendar\\Events\\CalendarObjectDeletedEvent' => $baseDir . '/lib/public/Calendar/Events/CalendarObjectDeletedEvent.php',
@@ -202,6 +203,7 @@ return array(
     'OCP\\Calendar\\IAvailabilityResult' => $baseDir . '/lib/public/Calendar/IAvailabilityResult.php',
     'OCP\\Calendar\\ICalendar' => $baseDir . '/lib/public/Calendar/ICalendar.php',
     'OCP\\Calendar\\ICalendarEventBuilder' => $baseDir . '/lib/public/Calendar/ICalendarEventBuilder.php',
+    'OCP\\Calendar\\ICalendarExport' => $baseDir . '/lib/public/Calendar/ICalendarExport.php',
     'OCP\\Calendar\\ICalendarIsShared' => $baseDir . '/lib/public/Calendar/ICalendarIsShared.php',
     'OCP\\Calendar\\ICalendarIsWritable' => $baseDir . '/lib/public/Calendar/ICalendarIsWritable.php',
     'OCP\\Calendar\\ICalendarProvider' => $baseDir . '/lib/public/Calendar/ICalendarProvider.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index 5771a621afe..ddccd0692ca 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -232,6 +232,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\Cache\\CappedMemoryCache' => __DIR__ . '/../../..' . '/lib/public/Cache/CappedMemoryCache.php',
         'OCP\\Calendar\\BackendTemporarilyUnavailableException' => __DIR__ . '/../../..' . '/lib/public/Calendar/BackendTemporarilyUnavailableException.php',
         'OCP\\Calendar\\CalendarEventStatus' => __DIR__ . '/../../..' . '/lib/public/Calendar/CalendarEventStatus.php',
+        'OCP\\Calendar\\CalendarExportOptions' => __DIR__ . '/../../..' . '/lib/public/Calendar/CalendarExportOptions.php',
         'OCP\\Calendar\\Events\\AbstractCalendarObjectEvent' => __DIR__ . '/../../..' . '/lib/public/Calendar/Events/AbstractCalendarObjectEvent.php',
         'OCP\\Calendar\\Events\\CalendarObjectCreatedEvent' => __DIR__ . '/../../..' . '/lib/public/Calendar/Events/CalendarObjectCreatedEvent.php',
         'OCP\\Calendar\\Events\\CalendarObjectDeletedEvent' => __DIR__ . '/../../..' . '/lib/public/Calendar/Events/CalendarObjectDeletedEvent.php',
@@ -243,6 +244,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\Calendar\\IAvailabilityResult' => __DIR__ . '/../../..' . '/lib/public/Calendar/IAvailabilityResult.php',
         'OCP\\Calendar\\ICalendar' => __DIR__ . '/../../..' . '/lib/public/Calendar/ICalendar.php',
         'OCP\\Calendar\\ICalendarEventBuilder' => __DIR__ . '/../../..' . '/lib/public/Calendar/ICalendarEventBuilder.php',
+        'OCP\\Calendar\\ICalendarExport' => __DIR__ . '/../../..' . '/lib/public/Calendar/ICalendarExport.php',
         'OCP\\Calendar\\ICalendarIsShared' => __DIR__ . '/../../..' . '/lib/public/Calendar/ICalendarIsShared.php',
         'OCP\\Calendar\\ICalendarIsWritable' => __DIR__ . '/../../..' . '/lib/public/Calendar/ICalendarIsWritable.php',
         'OCP\\Calendar\\ICalendarProvider' => __DIR__ . '/../../..' . '/lib/public/Calendar/ICalendarProvider.php',
diff --git a/lib/public/Calendar/CalendarExportOptions.php b/lib/public/Calendar/CalendarExportOptions.php
new file mode 100644
index 00000000000..bf21dd85ae4
--- /dev/null
+++ b/lib/public/Calendar/CalendarExportOptions.php
@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Calendar;
+
+/**
+ * Calendar Export Options
+ *
+ * @since 32.0.0
+ */
+final class CalendarExportOptions {
+
+	/** @var 'ical'|'jcal'|'xcal' */
+	private string $format = 'ical';
+	private ?string $rangeStart = null;
+	private ?int $rangeCount = null;
+
+	/**
+	 * Gets the export format
+	 *
+	 * @return 'ical'|'jcal'|'xcal' (defaults to ical)
+	 */
+	public function getFormat(): string {
+		return $this->format;
+	}
+
+	/**
+	 * Sets the export format
+	 *
+	 * @param 'ical'|'jcal'|'xcal' $format
+	 */
+	public function setFormat(string $format): void {
+		$this->format = $format;
+	}
+
+	/**
+	 * Gets the start of the range to export
+	 */
+	public function getRangeStart(): ?string {
+		return $this->rangeStart;
+	}
+
+	/**
+	 * Sets the start of the range to export
+	 */
+	public function setRangeStart(?string $rangeStart): void {
+		$this->rangeStart = $rangeStart;
+	}
+
+	/**
+	 * Gets the number of objects to export
+	 */
+	public function getRangeCount(): ?int {
+		return $this->rangeCount;
+	}
+
+	/**
+	 * Sets the number of objects to export
+	 */
+	public function setRangeCount(?int $rangeCount): void {
+		$this->rangeCount = $rangeCount;
+	}
+}
diff --git a/lib/public/Calendar/ICalendarExport.php b/lib/public/Calendar/ICalendarExport.php
new file mode 100644
index 00000000000..61b286e1668
--- /dev/null
+++ b/lib/public/Calendar/ICalendarExport.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Calendar;
+
+use Generator;
+
+/**
+ * ICalendar Interface Extension to export data
+ *
+ * @since 32.0.0
+ */
+interface ICalendarExport {
+	
+	/**
+	 * Export objects
+	 *
+	 * @since 32.0.0
+	 *
+	 * @param CalendarExportOptions|null $options
+	 *
+	 * @return Generator<\Sabre\VObject\Component\VCalendar>
+	 */
+	public function export(?CalendarExportOptions $options): Generator;
+
+}