Add exportable endpoint

Signed-off-by: Christopher Ng <[email protected]>

appinfo/routes.php

@@ -33,7 +33,7 @@
 		['name' => 'Api#migrators', 'url' => '/api/v{apiVersion}/migrators', 'verb' => 'GET', 'requirements' => $requirements],
 		['name' => 'Api#status', 'url' => '/api/v{apiVersion}/status', 'verb' => 'GET', 'requirements' => $requirements],
 		['name' => 'Api#cancel', 'url' => '/api/v{apiVersion}/cancel', 'verb' => 'PUT', 'requirements' => $requirements],
-		['name' => 'Api#estimateExportSize', 'url' => '/api/v{apiVersion}/estimate', 'verb' => 'POST', 'requirements' => $requirements],
+		['name' => 'Api#exportable', 'url' => '/api/v{apiVersion}/exportable', 'verb' => 'GET', 'requirements' => $requirements],
 		['name' => 'Api#export', 'url' => '/api/v{apiVersion}/export', 'verb' => 'POST', 'requirements' => $requirements],
 		['name' => 'Api#import', 'url' => '/api/v{apiVersion}/import', 'verb' => 'POST', 'requirements' => $requirements],
 	],

lib/Controller/ApiController.php

@@ -29,6 +29,7 @@
 use OCA\UserMigration\AppInfo\Application;
 use OCA\UserMigration\Db\UserExport;
 use OCA\UserMigration\Db\UserImport;
+use OCA\UserMigration\Service\NotExportableException;
 use OCA\UserMigration\Service\UserMigrationService;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
@@ -170,6 +171,23 @@ public function cancel(): DataResponse {
 		return new DataResponse([], Http::STATUS_OK);
 	}
 
+	/**
+	 * @throws OCSException
+	 */
+	private function checkMigrators(array $migrators): void {
+		/** @var string[] $availableMigrators */
+		$availableMigrators = array_map(
+			fn (IMigrator $migrator) => $migrator->getId(),
+			$this->migrationService->getMigrators(),
+		);
+
+		foreach ($migrators as $migrator) {
+			if (!in_array($migrator, $availableMigrators, true)) {
+				throw new OCSException("Requested migrator \"$migrator\" not available");
+			}
+		}
+	}
+
 	/**
 	 * @throws OCSException
 	 */
@@ -199,28 +217,20 @@ private function checkJobAndGetUser(): IUser {
 	 *
 	 * @throws OCSException
 	 */
-	public function estimateExportSize(array $migrators): DataResponse {
+	public function exportable(?array $migrators): DataResponse {
 		$user = $this->checkJobAndGetUser();
 
-		/** @var string[] $availableMigrators */
-		$availableMigrators = array_map(
-			fn (IMigrator $migrator) => $migrator->getId(),
-			$this->migrationService->getMigrators(),
-		);
-
-		foreach ($migrators as $migrator) {
-			if (!in_array($migrator, $availableMigrators, true)) {
-				throw new OCSException("Requested migrator \"$migrator\" not available");
-			}
+		if (!is_null($migrators)) {
+			$this->checkMigrators($migrators);
 		}
 
 		try {
-			$size = $this->migrationService->estimateExportSize($user, $migrators);
-		} catch (UserMigrationException $e) {
-			throw new OCSException('Error estimating export size');
+			$this->migrationService->checkExportability($user, $migrators);
+		} catch (NotExportableException $e) {
+			throw new OCSException($e->getMessage());
 		}
 
-		return new DataResponse(['kibibytes' => $size], Http::STATUS_OK);
+		return new DataResponse([], Http::STATUS_OK);
 	}
 
 	/**
@@ -232,18 +242,7 @@ public function estimateExportSize(array $migrators): DataResponse {
 	 */
 	public function export(array $migrators): DataResponse {
 		$user = $this->checkJobAndGetUser();
-
-		/** @var string[] $availableMigrators */
-		$availableMigrators = array_map(
-			fn (IMigrator $migrator) => $migrator->getId(),
-			$this->migrationService->getMigrators(),
-		);
-
-		foreach ($migrators as $migrator) {
-			if (!in_array($migrator, $availableMigrators, true)) {
-				throw new OCSException("Requested migrator \"$migrator\" not available");
-			}
-		}
+		$this->checkMigrators($migrators);
 
 		try {
 			$this->migrationService->queueExportJob($user, $migrators);

lib/Service/NotExportableException.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2022 Christopher Ng <[email protected]>
+ *
+ * @author Christopher Ng <[email protected]>
+ *
+ * @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\UserMigration\Service;
+
+use Exception;
+
+class NotExportableException extends Exception {
+}

lib/Service/UserMigrationService.php

@@ -27,6 +27,8 @@
 
 namespace OCA\UserMigration\Service;
 
+use OC_Helper;
+use OC_Util;
 use OC\AppFramework\Bootstrap\Coordinator;
 use OC\Cache\CappedMemoryCache;
 use OCA\UserMigration\BackgroundJob\UserExportJob;
@@ -104,9 +106,10 @@ public function __construct(
 
 	/**
 	 * @param ?string[] $filteredMigratorList If not null, only these migrators will run. If empty only the main account data will be exported.
+	 *
 	 * @return int Estimated size in KiB
 	 */
-	public function estimateExportSize(IUser $user, ?array $filteredMigratorList = null): int {
+	private function estimateExportSize(IUser $user, ?array $filteredMigratorList = null): int {
 		$cacheKey = $user->getUID();
 		if ($filteredMigratorList !== null) {
 			$cacheKey .= '::' . json_encode($filteredMigratorList);
@@ -132,6 +135,35 @@ public function estimateExportSize(IUser $user, ?array $filteredMigratorList = n
 
 	/**
 	 * @param ?string[] $filteredMigratorList If not null, only these migrators will run. If empty only the main account data will be exported.
+	 *
+	 * @throws NotExportableException
+	 */
+	public function checkExportability(IUser $user, ?array $filteredMigratorList = null): void {
+		try {
+			OC_Util::tearDownFS();
+			OC_Util::setupFS($user->getUID());
+			$storageInfo = OC_Helper::getStorageInfo('/');
+			// TODO safe to cache?
+			$freeSpace = (int)ceil($storageInfo['free'] / 1024);
+		} catch (Throwable $e) {
+			throw new NotExportableException('Error calculating amount of free space available');
+		}
+
+		try {
+			$exportSize = $this->estimateExportSize($user, $filteredMigratorList);
+		} catch (UserMigrationException $e) {
+			throw new NotExportableException('Error estimating export size');
+		}
+
+		$freeSpaceAfterExport = $freeSpace - $exportSize;
+		if ($freeSpaceAfterExport < 0) {
+			throw new NotExportableException('Insufficient storage space available to export, please free up ' . (int)abs($freeSpaceAfterExport) . ' KiB or more to be able to export your data');
+		}
+	}
+
+	/**
+	 * @param ?string[] $filteredMigratorList If not null, only these migrators will run. If empty only the main account data will be exported.
+	 *
 	 * @throws UserMigrationException
 	 */
 	public function export(IExportDestination $exportDestination, IUser $user, ?array $filteredMigratorList = null, ?OutputInterface $output = null): void {