feat(files_sharing): reminder for link shares with expiration date

Signed-off-by: Stefan Cherniakov <luka-sama@pm.me>

2 files changed, 297 insertions, 0 deletions

diff --git a/apps/files_sharing/lib/Migration/Version31000Date20240821142813.php b/apps/files_sharing/lib/Migration/Version31000Date20240821142813.php
new file mode 100644
index 00000000000..b063902a380
--- /dev/null
+++ b/apps/files_sharing/lib/Migration/Version31000Date20240821142813.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Files_Sharing\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version31000Date20240821142813 extends SimpleMigrationStep {
+
+	/**
+	 * @param IOutput $output
+	 * @param Closure(): ISchemaWrapper $schemaClosure
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		$schema = $schemaClosure();
+		$table = $schema->getTable('share');
+		$table->addColumn('reminder_sent', Types::BOOLEAN, [
+			'notnull' => false,
+			'default' => false,
+		]);
+		return $schema;
+	}
+
+}
diff --git a/apps/files_sharing/lib/SharesReminderJob.php b/apps/files_sharing/lib/SharesReminderJob.php
new file mode 100644
index 00000000000..214e555f173
--- /dev/null
+++ b/apps/files_sharing/lib/SharesReminderJob.php
@@ -0,0 +1,261 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Files_Sharing;
+
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\TimedJob;
+use OCP\Constants;
+use OCP\DB\Exception;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\Defaults;
+use OCP\Files\NotFoundException;
+use OCP\IDBConnection;
+use OCP\IL10N;
+use OCP\IURLGenerator;
+use OCP\IUserManager;
+use OCP\L10N\IFactory;
+use OCP\Mail\IEMailTemplate;
+use OCP\Mail\IMailer;
+use OCP\Share\Exceptions\ShareNotFound;
+use OCP\Share\IManager;
+use OCP\Share\IShare;
+use OCP\Util;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Send a reminder via email to the sharee(s) if the folder is still empty a predefined time before the expiration date
+ */
+class SharesReminderJob extends TimedJob {
+	private const SECONDS_BEFORE_REMINDER = 86400;
+
+	public function __construct(
+		ITimeFactory                     $time,
+		private readonly IDBConnection   $db,
+		private readonly IManager        $shareManager,
+		private readonly IUserManager    $userManager,
+		private readonly LoggerInterface $logger,
+		private readonly IURLGenerator   $urlGenerator,
+		private readonly IFactory        $l10nFactory,
+		private readonly IMailer         $mailer,
+		private readonly Defaults        $defaults,
+	) {
+		parent::__construct($time);
+		$this->setInterval(3600);
+	}
+
+
+	/**
+	 * Makes the background job do its work
+	 *
+	 * @param array $argument unused argument
+	 * @throws Exception if a database error occurs
+	 */
+	public function run(mixed $argument): void {
+		$shares = $this->getShares();
+		[$foldersByEmail, $langByEmail] = $this->prepareReminders($shares);
+		$this->sendReminders($foldersByEmail, $langByEmail);
+	}
+
+	/**
+	 * Finds all folder shares of type user or email with expiration dates within the specified timeframe.
+	 * This method returns only those shares that have not yet received the reminder.
+	 *
+	 * @return array<IShare>
+	 * @throws Exception if a database error occurs
+	 */
+	private function getShares(): array {
+		$minDate = new \DateTime();
+		$maxDate = new \DateTime();
+		$maxDate->setTimestamp($maxDate->getTimestamp() + self::SECONDS_BEFORE_REMINDER);
+
+		$qb = $this->db->getQueryBuilder();
+		$qb->select('id', 'share_type')
+			->from('share')
+			->where(
+				$qb->expr()->andX(
+					$qb->expr()->orX(
+						$qb->expr()->eq('share_type', $qb->expr()->literal(IShare::TYPE_USER)),
+						$qb->expr()->eq('share_type', $qb->expr()->literal(IShare::TYPE_EMAIL))
+					),
+					$qb->expr()->eq('item_type', $qb->expr()->literal('folder')),
+					$qb->expr()->gte('expiration', $qb->createNamedParameter($minDate->format('Y-m-d H:i:s'))),
+					$qb->expr()->lt('expiration', $qb->createNamedParameter($maxDate->format('Y-m-d H:i:s'))),
+					$qb->expr()->eq('reminder_sent', $qb->createNamedParameter(
+						false, IQueryBuilder::PARAM_BOOL
+					))
+				)
+			);
+
+		$sharesResult = $qb->executeQuery();
+		$shares = [];
+		while ($share = $sharesResult->fetch()) {
+			if ((int)$share['share_type'] === IShare::TYPE_EMAIL) {
+				$id = "ocMailShare:$share[id]";
+			} else {
+				$id = "ocinternal:$share[id]";
+			}
+
+			try {
+				$shares[] = $this->shareManager->getShareById($id);
+			} catch (ShareNotFound) {
+				$this->logger->error("Share with ID $id not found.");
+			}
+		}
+		$sharesResult->closeCursor();
+		return $shares;
+	}
+
+	/**
+	 * Checks if the user should be reminded about this share.
+	 * If so, it will retrieve and return all the necessary data for this.
+	 * It also updates the reminder sent flag for the affected shares (to avoid multiple reminders).
+	 *
+	 * @param array<IShare> $shares Shares that were obtained with {@link getShares}
+	 * @return array<array> A tuple consisting of two dictionaries: folders and languages by email
+	 * @throws Exception if the reminder sent flag could not be saved
+	 */
+	private function prepareReminders(array $shares): array {
+		// This dictionary stores email addresses as keys and folder lists as values.
+		// It is used to ensure that each user receives no more than one email notification.
+		// The email will include the names and links of the folders that the user should be reminded of.
+		$foldersByEmail = [];
+		// Similar to the previous one, this variable stores the language for each email (if provided)
+		$langByEmail = [];
+
+		/** @var IShare $share */
+		foreach ($shares as $share) {
+			if (!$this->shouldRemindOfThisShare($share)) {
+				continue;
+			}
+
+			$sharedWith = $share->getSharedWith();
+			if ($share->getShareType() == IShare::TYPE_USER) {
+				$user = $this->userManager->get($sharedWith);
+				$mailTo = $user->getEMailAddress();
+				$lang = $this->l10nFactory->getUserLanguage($user);
+				$link = $this->urlGenerator->linkToRouteAbsolute('files.view.index', [
+					'dir' => $share->getTarget()
+				]);
+			} else {
+				$mailTo = $sharedWith;
+				$lang = '';
+				$link = $this->urlGenerator->linkToRouteAbsolute('files_sharing.sharecontroller.showShare', [
+					'token' => $share->getToken()
+				]);
+			}
+			if (empty($mailTo)) {
+				continue;
+			}
+
+			if (!empty($lang)) {
+				$langByEmail[$mailTo] ??= $lang;
+			}
+			if (!isset($foldersByEmail[$mailTo])) {
+				$foldersByEmail[$mailTo] = [];
+			}
+			$foldersByEmail[$mailTo][] = ['name' => $share->getNode()->getName(), 'link' => $link];
+
+			$share->setReminderSent(true);
+			$qb = $this->db->getQueryBuilder();
+			$qb->update('share')
+				->where($qb->expr()->eq('id', $qb->createNamedParameter($share->getId())))
+				->set('reminder_sent', $qb->createNamedParameter($share->getReminderSent()))
+				->execute();
+		}
+
+		return [$foldersByEmail, $langByEmail];
+	}
+
+	/**
+	 * Checks if user has write permission and folder is empty
+	 *
+	 * @param IShare $share Share to check
+	 * @return bool
+	 */
+	private function shouldRemindOfThisShare(IShare $share): bool {
+		try {
+			$folder = $share->getNode();
+			$fileCount = count($folder->getDirectoryListing());
+		} catch (NotFoundException) {
+			$id = $share->getFullId();
+			$this->logger->debug("File by share ID $id not found.");
+			return false;
+		}
+		$permissions = $share->getPermissions();
+		$hasCreatePermission = ($permissions & Constants::PERMISSION_CREATE) === Constants::PERMISSION_CREATE;
+		return ($fileCount == 0 && $hasCreatePermission);
+	}
+
+	/**
+	 * This method accepts data obtained by {@link prepareReminders} and sends reminder emails.
+	 *
+	 * @param array $foldersByEmail
+	 * @param array $langByEmail
+	 * @return void
+	 */
+	private function sendReminders(array $foldersByEmail, array $langByEmail): void {
+		$instanceName = $this->defaults->getName();
+		$from = [Util::getDefaultEmailAddress($instanceName) => $instanceName];
+		foreach ($foldersByEmail as $email => $folders) {
+			$l = $this->l10nFactory->get('files_sharing', $langByEmail[$email] ?? null);
+			$emailTemplate = $this->generateEMailTemplate($l, $folders);
+			$message = $this->mailer->createMessage();
+			$message->setFrom($from);
+			$message->setTo([$email]);
+			$message->useTemplate($emailTemplate);
+			$errorText = "Sending email with share reminder to $email failed.";
+			try {
+				$failedRecipients = $this->mailer->send($message);
+				if (count($failedRecipients) > 0) {
+					$this->logger->error($errorText);
+				}
+			} catch (\Exception) {
+				$this->logger->error($errorText);
+			}
+		}
+	}
+
+	/**
+	 * Returns the reminder email template
+	 *
+	 * @param IL10N $l
+	 * @param array<array> $folders Folders the user should be reminded of
+	 * @return IEMailTemplate
+	 */
+	private function generateEMailTemplate(IL10N $l, array $folders): IEMailTemplate {
+		$emailTemplate = $this->mailer->createEMailTemplate('files_sharing.SharesReminder', [
+			'folders' => $folders,
+		]);
+
+		$emailTemplate->addHeader();
+		if (count($folders) == 1) {
+			$emailTemplate->setSubject(
+				$l->t('Remember to upload the files to %s', [$folders[0]['name']])
+			);
+			$emailTemplate->addBodyText($l->t(
+				'We would like to kindly remind you that you have not yet uploaded any files to the shared folder.'
+			));
+		} else {
+			$emailTemplate->setSubject(
+				$l->t('Remember to upload the files to shared folders')
+			);
+			$emailTemplate->addBodyText($l->t(
+				'We would like to kindly remind you that you have not yet uploaded any files to the shared folders.'
+			));
+		}
+
+		foreach ($folders as $folder) {
+			$emailTemplate->addBodyButton(
+				$l->t('Open "%s"', [$folder['name']]),
+				$folder['link']
+			);
+		}
+		$emailTemplate->addFooter();
+		return $emailTemplate;
+	}
+}