1 files changed, 107 insertions, 0 deletions
diff --git a/apps/dav/lib/CalDAV/Export/ExportService.php b/apps/dav/lib/CalDAV/Export/ExportService.php
new file mode 100644
index 00000000000..552b9e2b675
--- /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();
+	}
+
+}