Check if the offset exists before accessing

This checks if the offset exists before accessing it and also adds unit tests to this function which would have catched this before 

Fixes https://github.com/owncloud/core/issues/14277

apps/files/controller/apicontroller.php

 <?php
 /**
- * Copyright (c) 2014 Lukas Reschke <lukas@owncloud.com>
+ * Copyright (c) 2014-2015 Lukas Reschke <lukas@owncloud.com>
  * This file is licensed under the Affero General Public License version 3 or
  * later.
  * See the COPYING-README file.
@@ -17,19 +17,27 @@ use OCP\AppFramework\Http\DownloadResponse;
 use OC\Preview;
 use OCA\Files\Service\TagService;
 
+/**
+ * Class ApiController
+ *
+ * @package OCA\Files\Controller
+ */
 class ApiController extends Controller {
+	/** @var TagService */
+	private $tagService;
 
 	/**
-	 * @var TagService $tagService
+	 * @param string $appName
+	 * @param IRequest $request
+	 * @param TagService $tagService
 	 */
-	private $tagService;
-
-	public function __construct($appName, IRequest $request, TagService $tagService){
+	public function __construct($appName,
+								IRequest $request,
+								TagService $tagService){
 		parent::__construct($appName, $request);
 		$this->tagService = $tagService;
 	}
 
-
 	/**
 	 * Gets a thumbnail of the specified file
 	 *
@@ -66,25 +74,31 @@ class ApiController extends Controller {
 	 * @CORS
 	 *
 	 * @param string $path path
-	 * @param array  $tags array of tags
+	 * @param array|string $tags array of tags
 	 * @return DataResponse
 	 */
 	public function updateFileTags($path, $tags = null) {
-		$result = array();
+		$result = [];
 		// if tags specified or empty array, update tags
 		if (!is_null($tags)) {
 			try {
 				$this->tagService->updateFileTags($path, $tags);
 			} catch (\OCP\Files\NotFoundException $e) {
-				return new DataResponse(['message' => $e->getMessage()], Http::STATUS_NOT_FOUND);
+				return new DataResponse([
+					'message' => $e->getMessage()
+				], Http::STATUS_NOT_FOUND);
 			} catch (\OCP\Files\StorageNotAvailableException $e) {
-				return new DataResponse(['message' => $e->getMessage()], Http::STATUS_SERVICE_UNAVAILABLE);
+				return new DataResponse([
+					'message' => $e->getMessage()
+				], Http::STATUS_SERVICE_UNAVAILABLE);
 			} catch (\Exception $e) {
-				return new DataResponse(['message' => $e->getMessage()], Http::STATUS_NOT_FOUND);
+				return new DataResponse([
+					'message' => $e->getMessage()
+				], Http::STATUS_NOT_FOUND);
 			}
 			$result['tags'] = $tags;
 		}
-		return new DataResponse($result, Http::STATUS_OK);
+		return new DataResponse($result);
 	}
 
 	/**
@@ -93,7 +107,7 @@ class ApiController extends Controller {
 	 * @NoAdminRequired
 	 * @CORS
 	 *
-	 * @param array $tagName tag name to filter by
+	 * @param array|string $tagName tag name to filter by
 	 * @return DataResponse
 	 */
 	public function getFilesByTag($tagName) {
@@ -102,11 +116,15 @@ class ApiController extends Controller {
 		foreach ($fileInfos as &$fileInfo) {
 			$file = \OCA\Files\Helper::formatFileInfo($fileInfo);
 			$parts = explode('/', dirname($fileInfo->getPath()), 4);
-			$file['path'] = '/' . $parts[3];
-			$file['tags'] = array($tagName);
+			if(isset($parts[3])) {
+				$file['path'] = '/' . $parts[3];
+			} else {
+				$file['path'] = '/';
+			}
+			$file['tags'] = [$tagName];
 			$files[] = $file;
 		}
-		return new DataResponse(array('files' => $files), Http::STATUS_OK);
+		return new DataResponse(['files' => $files]);
 	}
 
 }

apps/files/tests/controller/apicontrollertest.php

+<?php
+/**
+ * Copyright (c) 2015 Lukas Reschke <lukas@owncloud.com>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+namespace OCA\Files\Controller;
+
+use OC\Files\FileInfo;
+use OCP\AppFramework\Http;
+use OC\Preview;
+use OCP\Files\NotFoundException;
+use OCP\Files\StorageNotAvailableException;
+use Test\TestCase;
+use OCP\IRequest;
+use OCA\Files\Service\TagService;
+use OCP\AppFramework\Http\DataResponse;
+
+/**
+ * Class ApiController
+ *
+ * @package OCA\Files\Controller
+ */
+class ApiControllerTest extends TestCase {
+	/** @var string */
+	private $appName = 'files';
+	/** @var IRequest */
+	private $request;
+	/** @var TagService */
+	private $tagService;
+	/** @var ApiController */
+	private $apiController;
+
+	public function setUp() {
+		$this->request = $this->getMockBuilder('\OCP\IRequest')
+			->disableOriginalConstructor()
+			->getMock();
+		$this->tagService = $this->getMockBuilder('\OCA\Files\Service\TagService')
+			->disableOriginalConstructor()
+			->getMock();
+
+		$this->apiController = new ApiController(
+			$this->appName,
+			$this->request,
+			$this->tagService
+		);
+	}
+
+	public function testGetFilesByTagEmpty() {
+		$tagName = 'MyTagName';
+		$this->tagService->expects($this->once())
+			->method('getFilesByTag')
+			->with($this->equalTo([$tagName]))
+			->will($this->returnValue([]));
+
+		$expected = new DataResponse(['files' => []]);
+		$this->assertEquals($expected, $this->apiController->getFilesByTag([$tagName]));
+	}
+
+	public function testGetFilesByTagSingle() {
+		$tagName = 'MyTagName';
+		$fileInfo = new FileInfo(
+			'/root.txt',
+			$this->getMockBuilder('\OC\Files\Storage\Storage')
+				->disableOriginalConstructor()
+				->getMock(),
+			'/var/www/root.txt',
+			[
+				'mtime' => 55,
+				'mimetype' => 'application/pdf',
+				'size' => 1234,
+				'etag' => 'MyEtag',
+			],
+			$this->getMockBuilder('\OCP\Files\Mount\IMountPoint')
+				->disableOriginalConstructor()
+				->getMock()
+		);
+		$this->tagService->expects($this->once())
+			->method('getFilesByTag')
+			->with($this->equalTo([$tagName]))
+			->will($this->returnValue([$fileInfo]));
+
+		$expected = new DataResponse([
+			'files' => [
+				[
+					'id' => null,
+					'parentId' => null,
+					'date' => 'January 1, 1970 at 12:00:55 AM GMT+0',
+					'mtime' => 55000,
+					'icon' => \OCA\Files\Helper::determineIcon($fileInfo),
+					'name' => 'root.txt',
+					'permissions' => null,
+					'mimetype' => 'application/pdf',
+					'size' => 1234,
+					'type' => 'file',
+					'etag' => 'MyEtag',
+					'path' => '/',
+					'tags' => [
+						[
+							'MyTagName'
+						]
+					],
+				],
+			],
+		]);
+		$this->assertEquals($expected, $this->apiController->getFilesByTag([$tagName]));
+	}
+
+	public function testGetFilesByTagMultiple() {
+		$tagName = 'MyTagName';
+		$fileInfo1 = new FileInfo(
+			'/root.txt',
+			$this->getMockBuilder('\OC\Files\Storage\Storage')
+				->disableOriginalConstructor()
+				->getMock(),
+			'/var/www/root.txt',
+			[
+				'mtime' => 55,
+				'mimetype' => 'application/pdf',
+				'size' => 1234,
+				'etag' => 'MyEtag',
+			],
+			$this->getMockBuilder('\OCP\Files\Mount\IMountPoint')
+				->disableOriginalConstructor()
+				->getMock()
+		);
+		$fileInfo2 = new FileInfo(
+			'/root.txt',
+			$this->getMockBuilder('\OC\Files\Storage\Storage')
+				->disableOriginalConstructor()
+				->getMock(),
+			'/var/www/some/sub.txt',
+			[
+				'mtime' => 999,
+				'mimetype' => 'application/binary',
+				'size' => 9876,
+				'etag' => 'SubEtag',
+			],
+			$this->getMockBuilder('\OCP\Files\Mount\IMountPoint')
+				->disableOriginalConstructor()
+				->getMock()
+		);
+		$this->tagService->expects($this->once())
+			->method('getFilesByTag')
+			->with($this->equalTo([$tagName]))
+			->will($this->returnValue([$fileInfo1, $fileInfo2]));
+
+		$expected = new DataResponse([
+			'files' => [
+				[
+					'id' => null,
+					'parentId' => null,
+					'date' => 'January 1, 1970 at 12:00:55 AM GMT+0',
+					'mtime' => 55000,
+					'icon' => \OCA\Files\Helper::determineIcon($fileInfo1),
+					'name' => 'root.txt',
+					'permissions' => null,
+					'mimetype' => 'application/pdf',
+					'size' => 1234,
+					'type' => 'file',
+					'etag' => 'MyEtag',
+					'path' => '/',
+					'tags' => [
+						[
+							'MyTagName'
+						]
+					],
+				],
+				[
+					'id' => null,
+					'parentId' => null,
+					'date' => 'January 1, 1970 at 12:16:39 AM GMT+0',
+					'mtime' => 999000,
+					'icon' => \OCA\Files\Helper::determineIcon($fileInfo2),
+					'name' => 'root.txt',
+					'permissions' => null,
+					'mimetype' => 'application/binary',
+					'size' => 9876,
+					'type' => 'file',
+					'etag' => 'SubEtag',
+					'path' => '/',
+					'tags' => [
+						[
+							'MyTagName'
+						]
+					],
+				]
+			],
+		]);
+		$this->assertEquals($expected, $this->apiController->getFilesByTag([$tagName]));
+	}
+
+	public function testUpdateFileTagsEmpty() {
+		$expected = new DataResponse([]);
+		$this->assertEquals($expected, $this->apiController->updateFileTags('/path.txt'));
+	}
+
+	public function testUpdateFileTagsWorking() {
+		$this->tagService->expects($this->once())
+			->method('updateFileTags')
+			->with('/path.txt', ['Tag1', 'Tag2']);
+
+		$expected = new DataResponse([
+			'tags' => [
+				'Tag1',
+				'Tag2'
+			],
+		]);
+		$this->assertEquals($expected, $this->apiController->updateFileTags('/path.txt', ['Tag1', 'Tag2']));
+	}
+
+	public function testUpdateFileTagsNotFoundException() {
+		$this->tagService->expects($this->once())
+			->method('updateFileTags')
+			->with('/path.txt', ['Tag1', 'Tag2'])
+			->will($this->throwException(new NotFoundException('My error message')));
+
+		$expected = new DataResponse(['message' => 'My error message'], Http::STATUS_NOT_FOUND);
+		$this->assertEquals($expected, $this->apiController->updateFileTags('/path.txt', ['Tag1', 'Tag2']));
+	}
+
+	public function testUpdateFileTagsStorageNotAvailableException() {
+		$this->tagService->expects($this->once())
+			->method('updateFileTags')
+			->with('/path.txt', ['Tag1', 'Tag2'])
+			->will($this->throwException(new StorageNotAvailableException('My error message')));
+
+		$expected = new DataResponse(['message' => 'My error message'], Http::STATUS_SERVICE_UNAVAILABLE);
+		$this->assertEquals($expected, $this->apiController->updateFileTags('/path.txt', ['Tag1', 'Tag2']));
+	}
+
+	public function testUpdateFileTagsStorageGenericException() {
+		$this->tagService->expects($this->once())
+			->method('updateFileTags')
+			->with('/path.txt', ['Tag1', 'Tag2'])
+			->will($this->throwException(new \Exception('My error message')));
+
+		$expected = new DataResponse(['message' => 'My error message'], Http::STATUS_NOT_FOUND);
+		$this->assertEquals($expected, $this->apiController->updateFileTags('/path.txt', ['Tag1', 'Tag2']));
+	}
+}