nextcloud / server

lib/private/Files/Storage/DAV.php

Indentation +800 added lines, -800 removed lines

@@ -58,805 +58,805 @@
  * @package OC\Files\Storage
  */
 class DAV extends Common {
-	/** @var string */
-	protected $password;
-	/** @var string */
-	protected $user;
-	/** @var string */
-	protected $authType;
-	/** @var string */
-	protected $host;
-	/** @var bool */
-	protected $secure;
-	/** @var string */
-	protected $root;
-	/** @var string */
-	protected $certPath;
-	/** @var bool */
-	protected $ready;
-	/** @var Client */
-	protected $client;
-	/** @var ArrayCache */
-	protected $statCache;
-	/** @var \OCP\Http\Client\IClientService */
-	protected $httpClientService;
-
-	/**
-	 * @param array $params
-	 * @throws \Exception
-	 */
-	public function __construct($params) {
-		$this->statCache = new ArrayCache();
-		$this->httpClientService = \OC::$server->getHTTPClientService();
-		if (isset($params['host']) && isset($params['user']) && isset($params['password'])) {
-			$host = $params['host'];
-			//remove leading http[s], will be generated in createBaseUri()
-			if (substr($host, 0, 8) == "https://") $host = substr($host, 8);
-			else if (substr($host, 0, 7) == "http://") $host = substr($host, 7);
-			$this->host = $host;
-			$this->user = $params['user'];
-			$this->password = $params['password'];
-			if (isset($params['authType'])) {
-				$this->authType = $params['authType'];
-			}
-			if (isset($params['secure'])) {
-				if (is_string($params['secure'])) {
-					$this->secure = ($params['secure'] === 'true');
-				} else {
-					$this->secure = (bool)$params['secure'];
-				}
-			} else {
-				$this->secure = false;
-			}
-			if ($this->secure === true) {
-				// inject mock for testing
-				$certManager = \OC::$server->getCertificateManager();
-				if (is_null($certManager)) { //no user
-					$certManager = \OC::$server->getCertificateManager(null);
-				}
-				$certPath = $certManager->getAbsoluteBundlePath();
-				if (file_exists($certPath)) {
-					$this->certPath = $certPath;
-				}
-			}
-			$this->root = $params['root'] ?? '/';
-			$this->root = '/' . ltrim($this->root, '/');
-			$this->root = rtrim($this->root, '/') . '/';
-		} else {
-			throw new \Exception('Invalid webdav storage configuration');
-		}
-	}
-
-	protected function init() {
-		if ($this->ready) {
-			return;
-		}
-		$this->ready = true;
-
-		$settings = [
-			'baseUri' => $this->createBaseUri(),
-			'userName' => $this->user,
-			'password' => $this->password,
-		];
-		if (isset($this->authType)) {
-			$settings['authType'] = $this->authType;
-		}
-
-		$proxy = \OC::$server->getConfig()->getSystemValue('proxy', '');
-		if ($proxy !== '') {
-			$settings['proxy'] = $proxy;
-		}
-
-		$this->client = new Client($settings);
-		$this->client->setThrowExceptions(true);
-		if ($this->secure === true && $this->certPath) {
-			$this->client->addCurlSetting(CURLOPT_CAINFO, $this->certPath);
-		}
-	}
-
-	/**
-	 * Clear the stat cache
-	 */
-	public function clearStatCache() {
-		$this->statCache->clear();
-	}
-
-	/** {@inheritdoc} */
-	public function getId() {
-		return 'webdav::' . $this->user . '@' . $this->host . '/' . $this->root;
-	}
-
-	/** {@inheritdoc} */
-	public function createBaseUri() {
-		$baseUri = 'http';
-		if ($this->secure) {
-			$baseUri .= 's';
-		}
-		$baseUri .= '://' . $this->host . $this->root;
-		return $baseUri;
-	}
-
-	/** {@inheritdoc} */
-	public function mkdir($path) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		$result = $this->simpleResponse('MKCOL', $path, null, 201);
-		if ($result) {
-			$this->statCache->set($path, true);
-		}
-		return $result;
-	}
-
-	/** {@inheritdoc} */
-	public function rmdir($path) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		// FIXME: some WebDAV impl return 403 when trying to DELETE
-		// a non-empty folder
-		$result = $this->simpleResponse('DELETE', $path . '/', null, 204);
-		$this->statCache->clear($path . '/');
-		$this->statCache->remove($path);
-		return $result;
-	}
-
-	/** {@inheritdoc} */
-	public function opendir($path) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		try {
-			$response = $this->client->propFind(
-				$this->encodePath($path),
-				['{DAV:}getetag'],
-				1
-			);
-			if ($response === false) {
-				return false;
-			}
-			$content = [];
-			$files = array_keys($response);
-			array_shift($files); //the first entry is the current directory
-
-			if (!$this->statCache->hasKey($path)) {
-				$this->statCache->set($path, true);
-			}
-			foreach ($files as $file) {
-				$file = urldecode($file);
-				// do not store the real entry, we might not have all properties
-				if (!$this->statCache->hasKey($path)) {
-					$this->statCache->set($file, true);
-				}
-				$file = basename($file);
-				$content[] = $file;
-			}
-			return IteratorDirectory::wrap($content);
-		} catch (\Exception $e) {
-			$this->convertException($e, $path);
-		}
-		return false;
-	}
-
-	/**
-	 * Propfind call with cache handling.
-	 *
-	 * First checks if information is cached.
-	 * If not, request it from the server then store to cache.
-	 *
-	 * @param string $path path to propfind
-	 *
-	 * @return array|boolean propfind response or false if the entry was not found
-	 *
-	 * @throws ClientHttpException
-	 */
-	protected function propfind($path) {
-		$path = $this->cleanPath($path);
-		$cachedResponse = $this->statCache->get($path);
-		// we either don't know it, or we know it exists but need more details
-		if (is_null($cachedResponse) || $cachedResponse === true) {
-			$this->init();
-			try {
-				$response = $this->client->propFind(
-					$this->encodePath($path),
-					array(
-						'{DAV:}getlastmodified',
-						'{DAV:}getcontentlength',
-						'{DAV:}getcontenttype',
-						'{http://owncloud.org/ns}permissions',
-						'{http://open-collaboration-services.org/ns}share-permissions',
-						'{DAV:}resourcetype',
-						'{DAV:}getetag',
-					)
-				);
-				$this->statCache->set($path, $response);
-			} catch (ClientHttpException $e) {
-				if ($e->getHttpStatus() === 404 || $e->getHttpStatus() === 405) {
-					$this->statCache->clear($path . '/');
-					$this->statCache->set($path, false);
-					return false;
-				}
-				$this->convertException($e, $path);
-			} catch (\Exception $e) {
-				$this->convertException($e, $path);
-			}
-		} else {
-			$response = $cachedResponse;
-		}
-		return $response;
-	}
-
-	/** {@inheritdoc} */
-	public function filetype($path) {
-		try {
-			$response = $this->propfind($path);
-			if ($response === false) {
-				return false;
-			}
-			$responseType = [];
-			if (isset($response["{DAV:}resourcetype"])) {
-				/** @var ResourceType[] $response */
-				$responseType = $response["{DAV:}resourcetype"]->getValue();
-			}
-			return (count($responseType) > 0 and $responseType[0] == "{DAV:}collection") ? 'dir' : 'file';
-		} catch (\Exception $e) {
-			$this->convertException($e, $path);
-		}
-		return false;
-	}
-
-	/** {@inheritdoc} */
-	public function file_exists($path) {
-		try {
-			$path = $this->cleanPath($path);
-			$cachedState = $this->statCache->get($path);
-			if ($cachedState === false) {
-				// we know the file doesn't exist
-				return false;
-			} else if (!is_null($cachedState)) {
-				return true;
-			}
-			// need to get from server
-			return ($this->propfind($path) !== false);
-		} catch (\Exception $e) {
-			$this->convertException($e, $path);
-		}
-		return false;
-	}
-
-	/** {@inheritdoc} */
-	public function unlink($path) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		$result = $this->simpleResponse('DELETE', $path, null, 204);
-		$this->statCache->clear($path . '/');
-		$this->statCache->remove($path);
-		return $result;
-	}
-
-	/** {@inheritdoc} */
-	public function fopen($path, $mode) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		switch ($mode) {
-			case 'r':
-			case 'rb':
-				try {
-					$response = $this->httpClientService
-						->newClient()
-						->get($this->createBaseUri() . $this->encodePath($path), [
-							'auth' => [$this->user, $this->password],
-							'stream' => true
-						]);
-				} catch (\GuzzleHttp\Exception\ClientException $e) {
-					if ($e->getResponse() instanceof ResponseInterface
-						&& $e->getResponse()->getStatusCode() === 404) {
-						return false;
-					} else {
-						throw $e;
-					}
-				}
-
-				if ($response->getStatusCode() !== Http::STATUS_OK) {
-					if ($response->getStatusCode() === Http::STATUS_LOCKED) {
-						throw new \OCP\Lock\LockedException($path);
-					} else {
-						Util::writeLog("webdav client", 'Guzzle get returned status code ' . $response->getStatusCode(), ILogger::ERROR);
-					}
-				}
-
-				return $response->getBody();
-			case 'w':
-			case 'wb':
-			case 'a':
-			case 'ab':
-			case 'r+':
-			case 'w+':
-			case 'wb+':
-			case 'a+':
-			case 'x':
-			case 'x+':
-			case 'c':
-			case 'c+':
-				//emulate these
-				$tempManager = \OC::$server->getTempManager();
-				if (strrpos($path, '.') !== false) {
-					$ext = substr($path, strrpos($path, '.'));
-				} else {
-					$ext = '';
-				}
-				if ($this->file_exists($path)) {
-					if (!$this->isUpdatable($path)) {
-						return false;
-					}
-					if ($mode === 'w' or $mode === 'w+') {
-						$tmpFile = $tempManager->getTemporaryFile($ext);
-					} else {
-						$tmpFile = $this->getCachedFile($path);
-					}
-				} else {
-					if (!$this->isCreatable(dirname($path))) {
-						return false;
-					}
-					$tmpFile = $tempManager->getTemporaryFile($ext);
-				}
-				$handle = fopen($tmpFile, $mode);
-				return CallbackWrapper::wrap($handle, null, null, function () use ($path, $tmpFile) {
-					$this->writeBack($tmpFile, $path);
-				});
-		}
-	}
-
-	/**
-	 * @param string $tmpFile
-	 */
-	public function writeBack($tmpFile, $path) {
-		$this->uploadFile($tmpFile, $path);
-		unlink($tmpFile);
-	}
-
-	/** {@inheritdoc} */
-	public function free_space($path) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		try {
-			// TODO: cacheable ?
-			$response = $this->client->propfind($this->encodePath($path), ['{DAV:}quota-available-bytes']);
-			if ($response === false) {
-				return FileInfo::SPACE_UNKNOWN;
-			}
-			if (isset($response['{DAV:}quota-available-bytes'])) {
-				return (int)$response['{DAV:}quota-available-bytes'];
-			} else {
-				return FileInfo::SPACE_UNKNOWN;
-			}
-		} catch (\Exception $e) {
-			return FileInfo::SPACE_UNKNOWN;
-		}
-	}
-
-	/** {@inheritdoc} */
-	public function touch($path, $mtime = null) {
-		$this->init();
-		if (is_null($mtime)) {
-			$mtime = time();
-		}
-		$path = $this->cleanPath($path);
-
-		// if file exists, update the mtime, else create a new empty file
-		if ($this->file_exists($path)) {
-			try {
-				$this->statCache->remove($path);
-				$this->client->proppatch($this->encodePath($path), ['{DAV:}lastmodified' => $mtime]);
-				// non-owncloud clients might not have accepted the property, need to recheck it
-				$response = $this->client->propfind($this->encodePath($path), ['{DAV:}getlastmodified'], 0);
-				if ($response === false) {
-					return false;
-				}
-				if (isset($response['{DAV:}getlastmodified'])) {
-					$remoteMtime = strtotime($response['{DAV:}getlastmodified']);
-					if ($remoteMtime !== $mtime) {
-						// server has not accepted the mtime
-						return false;
-					}
-				}
-			} catch (ClientHttpException $e) {
-				if ($e->getHttpStatus() === 501) {
-					return false;
-				}
-				$this->convertException($e, $path);
-				return false;
-			} catch (\Exception $e) {
-				$this->convertException($e, $path);
-				return false;
-			}
-		} else {
-			$this->file_put_contents($path, '');
-		}
-		return true;
-	}
-
-	/**
-	 * @param string $path
-	 * @param string $data
-	 * @return int
-	 */
-	public function file_put_contents($path, $data) {
-		$path = $this->cleanPath($path);
-		$result = parent::file_put_contents($path, $data);
-		$this->statCache->remove($path);
-		return $result;
-	}
-
-	/**
-	 * @param string $path
-	 * @param string $target
-	 */
-	protected function uploadFile($path, $target) {
-		$this->init();
-
-		// invalidate
-		$target = $this->cleanPath($target);
-		$this->statCache->remove($target);
-		$source = fopen($path, 'r');
-
-		$this->httpClientService
-			->newClient()
-			->put($this->createBaseUri() . $this->encodePath($target), [
-				'body' => $source,
-				'auth' => [$this->user, $this->password]
-			]);
-
-		$this->removeCachedFile($target);
-	}
-
-	/** {@inheritdoc} */
-	public function rename($path1, $path2) {
-		$this->init();
-		$path1 = $this->cleanPath($path1);
-		$path2 = $this->cleanPath($path2);
-		try {
-			// overwrite directory ?
-			if ($this->is_dir($path2)) {
-				// needs trailing slash in destination
-				$path2 = rtrim($path2, '/') . '/';
-			}
-			$this->client->request(
-				'MOVE',
-				$this->encodePath($path1),
-				null,
-				[
-					'Destination' => $this->createBaseUri() . $this->encodePath($path2),
-				]
-			);
-			$this->statCache->clear($path1 . '/');
-			$this->statCache->clear($path2 . '/');
-			$this->statCache->set($path1, false);
-			$this->statCache->set($path2, true);
-			$this->removeCachedFile($path1);
-			$this->removeCachedFile($path2);
-			return true;
-		} catch (\Exception $e) {
-			$this->convertException($e);
-		}
-		return false;
-	}
-
-	/** {@inheritdoc} */
-	public function copy($path1, $path2) {
-		$this->init();
-		$path1 = $this->cleanPath($path1);
-		$path2 = $this->cleanPath($path2);
-		try {
-			// overwrite directory ?
-			if ($this->is_dir($path2)) {
-				// needs trailing slash in destination
-				$path2 = rtrim($path2, '/') . '/';
-			}
-			$this->client->request(
-				'COPY',
-				$this->encodePath($path1),
-				null,
-				[
-					'Destination' => $this->createBaseUri() . $this->encodePath($path2),
-				]
-			);
-			$this->statCache->clear($path2 . '/');
-			$this->statCache->set($path2, true);
-			$this->removeCachedFile($path2);
-			return true;
-		} catch (\Exception $e) {
-			$this->convertException($e);
-		}
-		return false;
-	}
-
-	/** {@inheritdoc} */
-	public function stat($path) {
-		try {
-			$response = $this->propfind($path);
-			if (!$response) {
-				return false;
-			}
-			return [
-				'mtime' => strtotime($response['{DAV:}getlastmodified']),
-				'size' => (int)isset($response['{DAV:}getcontentlength']) ? $response['{DAV:}getcontentlength'] : 0,
-			];
-		} catch (\Exception $e) {
-			$this->convertException($e, $path);
-		}
-		return array();
-	}
-
-	/** {@inheritdoc} */
-	public function getMimeType($path) {
-		$remoteMimetype = $this->getMimeTypeFromRemote($path);
-		if ($remoteMimetype === 'application/octet-stream') {
-			return \OC::$server->getMimeTypeDetector()->detectPath($path);
-		} else {
-			return $remoteMimetype;
-		}
-	}
-
-	public function getMimeTypeFromRemote($path) {
-		try {
-			$response = $this->propfind($path);
-			if ($response === false) {
-				return false;
-			}
-			$responseType = [];
-			if (isset($response["{DAV:}resourcetype"])) {
-				/** @var ResourceType[] $response */
-				$responseType = $response["{DAV:}resourcetype"]->getValue();
-			}
-			$type = (count($responseType) > 0 and $responseType[0] == "{DAV:}collection") ? 'dir' : 'file';
-			if ($type == 'dir') {
-				return 'httpd/unix-directory';
-			} elseif (isset($response['{DAV:}getcontenttype'])) {
-				return $response['{DAV:}getcontenttype'];
-			} else {
-				return 'application/octet-stream';
-			}
-		} catch (\Exception $e) {
-			return false;
-		}
-	}
-
-	/**
-	 * @param string $path
-	 * @return string
-	 */
-	public function cleanPath($path) {
-		if ($path === '') {
-			return $path;
-		}
-		$path = Filesystem::normalizePath($path);
-		// remove leading slash
-		return substr($path, 1);
-	}
-
-	/**
-	 * URL encodes the given path but keeps the slashes
-	 *
-	 * @param string $path to encode
-	 * @return string encoded path
-	 */
-	protected function encodePath($path) {
-		// slashes need to stay
-		return str_replace('%2F', '/', rawurlencode($path));
-	}
-
-	/**
-	 * @param string $method
-	 * @param string $path
-	 * @param string|resource|null $body
-	 * @param int $expected
-	 * @return bool
-	 * @throws StorageInvalidException
-	 * @throws StorageNotAvailableException
-	 */
-	protected function simpleResponse($method, $path, $body, $expected) {
-		$path = $this->cleanPath($path);
-		try {
-			$response = $this->client->request($method, $this->encodePath($path), $body);
-			return $response['statusCode'] == $expected;
-		} catch (ClientHttpException $e) {
-			if ($e->getHttpStatus() === 404 && $method === 'DELETE') {
-				$this->statCache->clear($path . '/');
-				$this->statCache->set($path, false);
-				return false;
-			}
-
-			$this->convertException($e, $path);
-		} catch (\Exception $e) {
-			$this->convertException($e, $path);
-		}
-		return false;
-	}
-
-	/**
-	 * check if curl is installed
-	 */
-	public static function checkDependencies() {
-		return true;
-	}
-
-	/** {@inheritdoc} */
-	public function isUpdatable($path) {
-		return (bool)($this->getPermissions($path) & Constants::PERMISSION_UPDATE);
-	}
-
-	/** {@inheritdoc} */
-	public function isCreatable($path) {
-		return (bool)($this->getPermissions($path) & Constants::PERMISSION_CREATE);
-	}
-
-	/** {@inheritdoc} */
-	public function isSharable($path) {
-		return (bool)($this->getPermissions($path) & Constants::PERMISSION_SHARE);
-	}
-
-	/** {@inheritdoc} */
-	public function isDeletable($path) {
-		return (bool)($this->getPermissions($path) & Constants::PERMISSION_DELETE);
-	}
-
-	/** {@inheritdoc} */
-	public function getPermissions($path) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		$response = $this->propfind($path);
-		if ($response === false) {
-			return 0;
-		}
-		if (isset($response['{http://owncloud.org/ns}permissions'])) {
-			return $this->parsePermissions($response['{http://owncloud.org/ns}permissions']);
-		} else if ($this->is_dir($path)) {
-			return Constants::PERMISSION_ALL;
-		} else if ($this->file_exists($path)) {
-			return Constants::PERMISSION_ALL - Constants::PERMISSION_CREATE;
-		} else {
-			return 0;
-		}
-	}
-
-	/** {@inheritdoc} */
-	public function getETag($path) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		$response = $this->propfind($path);
-		if ($response === false) {
-			return null;
-		}
-		if (isset($response['{DAV:}getetag'])) {
-			$etag = trim($response['{DAV:}getetag'], '"');
-			if (strlen($etag) > 40) {
-				$etag = md5($etag);
-			}
-			return $etag;
-		}
-		return parent::getEtag($path);
-	}
-
-	/**
-	 * @param string $permissionsString
-	 * @return int
-	 */
-	protected function parsePermissions($permissionsString) {
-		$permissions = Constants::PERMISSION_READ;
-		if (strpos($permissionsString, 'R') !== false) {
-			$permissions |= Constants::PERMISSION_SHARE;
-		}
-		if (strpos($permissionsString, 'D') !== false) {
-			$permissions |= Constants::PERMISSION_DELETE;
-		}
-		if (strpos($permissionsString, 'W') !== false) {
-			$permissions |= Constants::PERMISSION_UPDATE;
-		}
-		if (strpos($permissionsString, 'CK') !== false) {
-			$permissions |= Constants::PERMISSION_CREATE;
-			$permissions |= Constants::PERMISSION_UPDATE;
-		}
-		return $permissions;
-	}
-
-	/**
-	 * check if a file or folder has been updated since $time
-	 *
-	 * @param string $path
-	 * @param int $time
-	 * @throws \OCP\Files\StorageNotAvailableException
-	 * @return bool
-	 */
-	public function hasUpdated($path, $time) {
-		$this->init();
-		$path = $this->cleanPath($path);
-		try {
-			// force refresh for $path
-			$this->statCache->remove($path);
-			$response = $this->propfind($path);
-			if ($response === false) {
-				if ($path === '') {
-					// if root is gone it means the storage is not available
-					throw new StorageNotAvailableException('root is gone');
-				}
-				return false;
-			}
-			if (isset($response['{DAV:}getetag'])) {
-				$cachedData = $this->getCache()->get($path);
-				$etag = null;
-				if (isset($response['{DAV:}getetag'])) {
-					$etag = trim($response['{DAV:}getetag'], '"');
-				}
-				if (!empty($etag) && $cachedData['etag'] !== $etag) {
-					return true;
-				} else if (isset($response['{http://open-collaboration-services.org/ns}share-permissions'])) {
-					$sharePermissions = (int)$response['{http://open-collaboration-services.org/ns}share-permissions'];
-					return $sharePermissions !== $cachedData['permissions'];
-				} else if (isset($response['{http://owncloud.org/ns}permissions'])) {
-					$permissions = $this->parsePermissions($response['{http://owncloud.org/ns}permissions']);
-					return $permissions !== $cachedData['permissions'];
-				} else {
-					return false;
-				}
-			} else {
-				$remoteMtime = strtotime($response['{DAV:}getlastmodified']);
-				return $remoteMtime > $time;
-			}
-		} catch (ClientHttpException $e) {
-			if ($e->getHttpStatus() === 405) {
-				if ($path === '') {
-					// if root is gone it means the storage is not available
-					throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
-				}
-				return false;
-			}
-			$this->convertException($e, $path);
-			return false;
-		} catch (\Exception $e) {
-			$this->convertException($e, $path);
-			return false;
-		}
-	}
-
-	/**
-	 * Interpret the given exception and decide whether it is due to an
-	 * unavailable storage, invalid storage or other.
-	 * This will either throw StorageInvalidException, StorageNotAvailableException
-	 * or do nothing.
-	 *
-	 * @param Exception $e sabre exception
-	 * @param string $path optional path from the operation
-	 *
-	 * @throws StorageInvalidException if the storage is invalid, for example
-	 * when the authentication expired or is invalid
-	 * @throws StorageNotAvailableException if the storage is not available,
-	 * which might be temporary
-	 */
-	protected function convertException(Exception $e, $path = '') {
-		\OC::$server->getLogger()->logException($e, ['app' => 'files_external', 'level' => ILogger::DEBUG]);
-		if ($e instanceof ClientHttpException) {
-			if ($e->getHttpStatus() === Http::STATUS_LOCKED) {
-				throw new \OCP\Lock\LockedException($path);
-			}
-			if ($e->getHttpStatus() === Http::STATUS_UNAUTHORIZED) {
-				// either password was changed or was invalid all along
-				throw new StorageInvalidException(get_class($e) . ': ' . $e->getMessage());
-			} else if ($e->getHttpStatus() === Http::STATUS_METHOD_NOT_ALLOWED) {
-				// ignore exception for MethodNotAllowed, false will be returned
-				return;
-			}
-			throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
-		} else if ($e instanceof ClientException) {
-			// connection timeout or refused, server could be temporarily down
-			throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
-		} else if ($e instanceof \InvalidArgumentException) {
-			// parse error because the server returned HTML instead of XML,
-			// possibly temporarily down
-			throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
-		} else if (($e instanceof StorageNotAvailableException) || ($e instanceof StorageInvalidException)) {
-			// rethrow
-			throw $e;
-		}
-
-		// TODO: only log for now, but in the future need to wrap/rethrow exception
-	}
+    /** @var string */
+    protected $password;
+    /** @var string */
+    protected $user;
+    /** @var string */
+    protected $authType;
+    /** @var string */
+    protected $host;
+    /** @var bool */
+    protected $secure;
+    /** @var string */
+    protected $root;
+    /** @var string */
+    protected $certPath;
+    /** @var bool */
+    protected $ready;
+    /** @var Client */
+    protected $client;
+    /** @var ArrayCache */
+    protected $statCache;
+    /** @var \OCP\Http\Client\IClientService */
+    protected $httpClientService;
+
+    /**
+     * @param array $params
+     * @throws \Exception
+     */
+    public function __construct($params) {
+        $this->statCache = new ArrayCache();
+        $this->httpClientService = \OC::$server->getHTTPClientService();
+        if (isset($params['host']) && isset($params['user']) && isset($params['password'])) {
+            $host = $params['host'];
+            //remove leading http[s], will be generated in createBaseUri()
+            if (substr($host, 0, 8) == "https://") $host = substr($host, 8);
+            else if (substr($host, 0, 7) == "http://") $host = substr($host, 7);
+            $this->host = $host;
+            $this->user = $params['user'];
+            $this->password = $params['password'];
+            if (isset($params['authType'])) {
+                $this->authType = $params['authType'];
+            }
+            if (isset($params['secure'])) {
+                if (is_string($params['secure'])) {
+                    $this->secure = ($params['secure'] === 'true');
+                } else {
+                    $this->secure = (bool)$params['secure'];
+                }
+            } else {
+                $this->secure = false;
+            }
+            if ($this->secure === true) {
+                // inject mock for testing
+                $certManager = \OC::$server->getCertificateManager();
+                if (is_null($certManager)) { //no user
+                    $certManager = \OC::$server->getCertificateManager(null);
+                }
+                $certPath = $certManager->getAbsoluteBundlePath();
+                if (file_exists($certPath)) {
+                    $this->certPath = $certPath;
+                }
+            }
+            $this->root = $params['root'] ?? '/';
+            $this->root = '/' . ltrim($this->root, '/');
+            $this->root = rtrim($this->root, '/') . '/';
+        } else {
+            throw new \Exception('Invalid webdav storage configuration');
+        }
+    }
+
+    protected function init() {
+        if ($this->ready) {
+            return;
+        }
+        $this->ready = true;
+
+        $settings = [
+            'baseUri' => $this->createBaseUri(),
+            'userName' => $this->user,
+            'password' => $this->password,
+        ];
+        if (isset($this->authType)) {
+            $settings['authType'] = $this->authType;
+        }
+
+        $proxy = \OC::$server->getConfig()->getSystemValue('proxy', '');
+        if ($proxy !== '') {
+            $settings['proxy'] = $proxy;
+        }
+
+        $this->client = new Client($settings);
+        $this->client->setThrowExceptions(true);
+        if ($this->secure === true && $this->certPath) {
+            $this->client->addCurlSetting(CURLOPT_CAINFO, $this->certPath);
+        }
+    }
+
+    /**
+     * Clear the stat cache
+     */
+    public function clearStatCache() {
+        $this->statCache->clear();
+    }
+
+    /** {@inheritdoc} */
+    public function getId() {
+        return 'webdav::' . $this->user . '@' . $this->host . '/' . $this->root;
+    }
+
+    /** {@inheritdoc} */
+    public function createBaseUri() {
+        $baseUri = 'http';
+        if ($this->secure) {
+            $baseUri .= 's';
+        }
+        $baseUri .= '://' . $this->host . $this->root;
+        return $baseUri;
+    }
+
+    /** {@inheritdoc} */
+    public function mkdir($path) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        $result = $this->simpleResponse('MKCOL', $path, null, 201);
+        if ($result) {
+            $this->statCache->set($path, true);
+        }
+        return $result;
+    }
+
+    /** {@inheritdoc} */
+    public function rmdir($path) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        // FIXME: some WebDAV impl return 403 when trying to DELETE
+        // a non-empty folder
+        $result = $this->simpleResponse('DELETE', $path . '/', null, 204);
+        $this->statCache->clear($path . '/');
+        $this->statCache->remove($path);
+        return $result;
+    }
+
+    /** {@inheritdoc} */
+    public function opendir($path) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        try {
+            $response = $this->client->propFind(
+                $this->encodePath($path),
+                ['{DAV:}getetag'],
+                1
+            );
+            if ($response === false) {
+                return false;
+            }
+            $content = [];
+            $files = array_keys($response);
+            array_shift($files); //the first entry is the current directory
+
+            if (!$this->statCache->hasKey($path)) {
+                $this->statCache->set($path, true);
+            }
+            foreach ($files as $file) {
+                $file = urldecode($file);
+                // do not store the real entry, we might not have all properties
+                if (!$this->statCache->hasKey($path)) {
+                    $this->statCache->set($file, true);
+                }
+                $file = basename($file);
+                $content[] = $file;
+            }
+            return IteratorDirectory::wrap($content);
+        } catch (\Exception $e) {
+            $this->convertException($e, $path);
+        }
+        return false;
+    }
+
+    /**
+     * Propfind call with cache handling.
+     *
+     * First checks if information is cached.
+     * If not, request it from the server then store to cache.
+     *
+     * @param string $path path to propfind
+     *
+     * @return array|boolean propfind response or false if the entry was not found
+     *
+     * @throws ClientHttpException
+     */
+    protected function propfind($path) {
+        $path = $this->cleanPath($path);
+        $cachedResponse = $this->statCache->get($path);
+        // we either don't know it, or we know it exists but need more details
+        if (is_null($cachedResponse) || $cachedResponse === true) {
+            $this->init();
+            try {
+                $response = $this->client->propFind(
+                    $this->encodePath($path),
+                    array(
+                        '{DAV:}getlastmodified',
+                        '{DAV:}getcontentlength',
+                        '{DAV:}getcontenttype',
+                        '{http://owncloud.org/ns}permissions',
+                        '{http://open-collaboration-services.org/ns}share-permissions',
+                        '{DAV:}resourcetype',
+                        '{DAV:}getetag',
+                    )
+                );
+                $this->statCache->set($path, $response);
+            } catch (ClientHttpException $e) {
+                if ($e->getHttpStatus() === 404 || $e->getHttpStatus() === 405) {
+                    $this->statCache->clear($path . '/');
+                    $this->statCache->set($path, false);
+                    return false;
+                }
+                $this->convertException($e, $path);
+            } catch (\Exception $e) {
+                $this->convertException($e, $path);
+            }
+        } else {
+            $response = $cachedResponse;
+        }
+        return $response;
+    }
+
+    /** {@inheritdoc} */
+    public function filetype($path) {
+        try {
+            $response = $this->propfind($path);
+            if ($response === false) {
+                return false;
+            }
+            $responseType = [];
+            if (isset($response["{DAV:}resourcetype"])) {
+                /** @var ResourceType[] $response */
+                $responseType = $response["{DAV:}resourcetype"]->getValue();
+            }
+            return (count($responseType) > 0 and $responseType[0] == "{DAV:}collection") ? 'dir' : 'file';
+        } catch (\Exception $e) {
+            $this->convertException($e, $path);
+        }
+        return false;
+    }
+
+    /** {@inheritdoc} */
+    public function file_exists($path) {
+        try {
+            $path = $this->cleanPath($path);
+            $cachedState = $this->statCache->get($path);
+            if ($cachedState === false) {
+                // we know the file doesn't exist
+                return false;
+            } else if (!is_null($cachedState)) {
+                return true;
+            }
+            // need to get from server
+            return ($this->propfind($path) !== false);
+        } catch (\Exception $e) {
+            $this->convertException($e, $path);
+        }
+        return false;
+    }
+
+    /** {@inheritdoc} */
+    public function unlink($path) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        $result = $this->simpleResponse('DELETE', $path, null, 204);
+        $this->statCache->clear($path . '/');
+        $this->statCache->remove($path);
+        return $result;
+    }
+
+    /** {@inheritdoc} */
+    public function fopen($path, $mode) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        switch ($mode) {
+            case 'r':
+            case 'rb':
+                try {
+                    $response = $this->httpClientService
+                        ->newClient()
+                        ->get($this->createBaseUri() . $this->encodePath($path), [
+                            'auth' => [$this->user, $this->password],
+                            'stream' => true
+                        ]);
+                } catch (\GuzzleHttp\Exception\ClientException $e) {
+                    if ($e->getResponse() instanceof ResponseInterface
+                        && $e->getResponse()->getStatusCode() === 404) {
+                        return false;
+                    } else {
+                        throw $e;
+                    }
+                }
+
+                if ($response->getStatusCode() !== Http::STATUS_OK) {
+                    if ($response->getStatusCode() === Http::STATUS_LOCKED) {
+                        throw new \OCP\Lock\LockedException($path);
+                    } else {
+                        Util::writeLog("webdav client", 'Guzzle get returned status code ' . $response->getStatusCode(), ILogger::ERROR);
+                    }
+                }
+
+                return $response->getBody();
+            case 'w':
+            case 'wb':
+            case 'a':
+            case 'ab':
+            case 'r+':
+            case 'w+':
+            case 'wb+':
+            case 'a+':
+            case 'x':
+            case 'x+':
+            case 'c':
+            case 'c+':
+                //emulate these
+                $tempManager = \OC::$server->getTempManager();
+                if (strrpos($path, '.') !== false) {
+                    $ext = substr($path, strrpos($path, '.'));
+                } else {
+                    $ext = '';
+                }
+                if ($this->file_exists($path)) {
+                    if (!$this->isUpdatable($path)) {
+                        return false;
+                    }
+                    if ($mode === 'w' or $mode === 'w+') {
+                        $tmpFile = $tempManager->getTemporaryFile($ext);
+                    } else {
+                        $tmpFile = $this->getCachedFile($path);
+                    }
+                } else {
+                    if (!$this->isCreatable(dirname($path))) {
+                        return false;
+                    }
+                    $tmpFile = $tempManager->getTemporaryFile($ext);
+                }
+                $handle = fopen($tmpFile, $mode);
+                return CallbackWrapper::wrap($handle, null, null, function () use ($path, $tmpFile) {
+                    $this->writeBack($tmpFile, $path);
+                });
+        }
+    }
+
+    /**
+     * @param string $tmpFile
+     */
+    public function writeBack($tmpFile, $path) {
+        $this->uploadFile($tmpFile, $path);
+        unlink($tmpFile);
+    }
+
+    /** {@inheritdoc} */
+    public function free_space($path) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        try {
+            // TODO: cacheable ?
+            $response = $this->client->propfind($this->encodePath($path), ['{DAV:}quota-available-bytes']);
+            if ($response === false) {
+                return FileInfo::SPACE_UNKNOWN;
+            }
+            if (isset($response['{DAV:}quota-available-bytes'])) {
+                return (int)$response['{DAV:}quota-available-bytes'];
+            } else {
+                return FileInfo::SPACE_UNKNOWN;
+            }
+        } catch (\Exception $e) {
+            return FileInfo::SPACE_UNKNOWN;
+        }
+    }
+
+    /** {@inheritdoc} */
+    public function touch($path, $mtime = null) {
+        $this->init();
+        if (is_null($mtime)) {
+            $mtime = time();
+        }
+        $path = $this->cleanPath($path);
+
+        // if file exists, update the mtime, else create a new empty file
+        if ($this->file_exists($path)) {
+            try {
+                $this->statCache->remove($path);
+                $this->client->proppatch($this->encodePath($path), ['{DAV:}lastmodified' => $mtime]);
+                // non-owncloud clients might not have accepted the property, need to recheck it
+                $response = $this->client->propfind($this->encodePath($path), ['{DAV:}getlastmodified'], 0);
+                if ($response === false) {
+                    return false;
+                }
+                if (isset($response['{DAV:}getlastmodified'])) {
+                    $remoteMtime = strtotime($response['{DAV:}getlastmodified']);
+                    if ($remoteMtime !== $mtime) {
+                        // server has not accepted the mtime
+                        return false;
+                    }
+                }
+            } catch (ClientHttpException $e) {
+                if ($e->getHttpStatus() === 501) {
+                    return false;
+                }
+                $this->convertException($e, $path);
+                return false;
+            } catch (\Exception $e) {
+                $this->convertException($e, $path);
+                return false;
+            }
+        } else {
+            $this->file_put_contents($path, '');
+        }
+        return true;
+    }
+
+    /**
+     * @param string $path
+     * @param string $data
+     * @return int
+     */
+    public function file_put_contents($path, $data) {
+        $path = $this->cleanPath($path);
+        $result = parent::file_put_contents($path, $data);
+        $this->statCache->remove($path);
+        return $result;
+    }
+
+    /**
+     * @param string $path
+     * @param string $target
+     */
+    protected function uploadFile($path, $target) {
+        $this->init();
+
+        // invalidate
+        $target = $this->cleanPath($target);
+        $this->statCache->remove($target);
+        $source = fopen($path, 'r');
+
+        $this->httpClientService
+            ->newClient()
+            ->put($this->createBaseUri() . $this->encodePath($target), [
+                'body' => $source,
+                'auth' => [$this->user, $this->password]
+            ]);
+
+        $this->removeCachedFile($target);
+    }
+
+    /** {@inheritdoc} */
+    public function rename($path1, $path2) {
+        $this->init();
+        $path1 = $this->cleanPath($path1);
+        $path2 = $this->cleanPath($path2);
+        try {
+            // overwrite directory ?
+            if ($this->is_dir($path2)) {
+                // needs trailing slash in destination
+                $path2 = rtrim($path2, '/') . '/';
+            }
+            $this->client->request(
+                'MOVE',
+                $this->encodePath($path1),
+                null,
+                [
+                    'Destination' => $this->createBaseUri() . $this->encodePath($path2),
+                ]
+            );
+            $this->statCache->clear($path1 . '/');
+            $this->statCache->clear($path2 . '/');
+            $this->statCache->set($path1, false);
+            $this->statCache->set($path2, true);
+            $this->removeCachedFile($path1);
+            $this->removeCachedFile($path2);
+            return true;
+        } catch (\Exception $e) {
+            $this->convertException($e);
+        }
+        return false;
+    }
+
+    /** {@inheritdoc} */
+    public function copy($path1, $path2) {
+        $this->init();
+        $path1 = $this->cleanPath($path1);
+        $path2 = $this->cleanPath($path2);
+        try {
+            // overwrite directory ?
+            if ($this->is_dir($path2)) {
+                // needs trailing slash in destination
+                $path2 = rtrim($path2, '/') . '/';
+            }
+            $this->client->request(
+                'COPY',
+                $this->encodePath($path1),
+                null,
+                [
+                    'Destination' => $this->createBaseUri() . $this->encodePath($path2),
+                ]
+            );
+            $this->statCache->clear($path2 . '/');
+            $this->statCache->set($path2, true);
+            $this->removeCachedFile($path2);
+            return true;
+        } catch (\Exception $e) {
+            $this->convertException($e);
+        }
+        return false;
+    }
+
+    /** {@inheritdoc} */
+    public function stat($path) {
+        try {
+            $response = $this->propfind($path);
+            if (!$response) {
+                return false;
+            }
+            return [
+                'mtime' => strtotime($response['{DAV:}getlastmodified']),
+                'size' => (int)isset($response['{DAV:}getcontentlength']) ? $response['{DAV:}getcontentlength'] : 0,
+            ];
+        } catch (\Exception $e) {
+            $this->convertException($e, $path);
+        }
+        return array();
+    }
+
+    /** {@inheritdoc} */
+    public function getMimeType($path) {
+        $remoteMimetype = $this->getMimeTypeFromRemote($path);
+        if ($remoteMimetype === 'application/octet-stream') {
+            return \OC::$server->getMimeTypeDetector()->detectPath($path);
+        } else {
+            return $remoteMimetype;
+        }
+    }
+
+    public function getMimeTypeFromRemote($path) {
+        try {
+            $response = $this->propfind($path);
+            if ($response === false) {
+                return false;
+            }
+            $responseType = [];
+            if (isset($response["{DAV:}resourcetype"])) {
+                /** @var ResourceType[] $response */
+                $responseType = $response["{DAV:}resourcetype"]->getValue();
+            }
+            $type = (count($responseType) > 0 and $responseType[0] == "{DAV:}collection") ? 'dir' : 'file';
+            if ($type == 'dir') {
+                return 'httpd/unix-directory';
+            } elseif (isset($response['{DAV:}getcontenttype'])) {
+                return $response['{DAV:}getcontenttype'];
+            } else {
+                return 'application/octet-stream';
+            }
+        } catch (\Exception $e) {
+            return false;
+        }
+    }
+
+    /**
+     * @param string $path
+     * @return string
+     */
+    public function cleanPath($path) {
+        if ($path === '') {
+            return $path;
+        }
+        $path = Filesystem::normalizePath($path);
+        // remove leading slash
+        return substr($path, 1);
+    }
+
+    /**
+     * URL encodes the given path but keeps the slashes
+     *
+     * @param string $path to encode
+     * @return string encoded path
+     */
+    protected function encodePath($path) {
+        // slashes need to stay
+        return str_replace('%2F', '/', rawurlencode($path));
+    }
+
+    /**
+     * @param string $method
+     * @param string $path
+     * @param string|resource|null $body
+     * @param int $expected
+     * @return bool
+     * @throws StorageInvalidException
+     * @throws StorageNotAvailableException
+     */
+    protected function simpleResponse($method, $path, $body, $expected) {
+        $path = $this->cleanPath($path);
+        try {
+            $response = $this->client->request($method, $this->encodePath($path), $body);
+            return $response['statusCode'] == $expected;
+        } catch (ClientHttpException $e) {
+            if ($e->getHttpStatus() === 404 && $method === 'DELETE') {
+                $this->statCache->clear($path . '/');
+                $this->statCache->set($path, false);
+                return false;
+            }
+
+            $this->convertException($e, $path);
+        } catch (\Exception $e) {
+            $this->convertException($e, $path);
+        }
+        return false;
+    }
+
+    /**
+     * check if curl is installed
+     */
+    public static function checkDependencies() {
+        return true;
+    }
+
+    /** {@inheritdoc} */
+    public function isUpdatable($path) {
+        return (bool)($this->getPermissions($path) & Constants::PERMISSION_UPDATE);
+    }
+
+    /** {@inheritdoc} */
+    public function isCreatable($path) {
+        return (bool)($this->getPermissions($path) & Constants::PERMISSION_CREATE);
+    }
+
+    /** {@inheritdoc} */
+    public function isSharable($path) {
+        return (bool)($this->getPermissions($path) & Constants::PERMISSION_SHARE);
+    }
+
+    /** {@inheritdoc} */
+    public function isDeletable($path) {
+        return (bool)($this->getPermissions($path) & Constants::PERMISSION_DELETE);
+    }
+
+    /** {@inheritdoc} */
+    public function getPermissions($path) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        $response = $this->propfind($path);
+        if ($response === false) {
+            return 0;
+        }
+        if (isset($response['{http://owncloud.org/ns}permissions'])) {
+            return $this->parsePermissions($response['{http://owncloud.org/ns}permissions']);
+        } else if ($this->is_dir($path)) {
+            return Constants::PERMISSION_ALL;
+        } else if ($this->file_exists($path)) {
+            return Constants::PERMISSION_ALL - Constants::PERMISSION_CREATE;
+        } else {
+            return 0;
+        }
+    }
+
+    /** {@inheritdoc} */
+    public function getETag($path) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        $response = $this->propfind($path);
+        if ($response === false) {
+            return null;
+        }
+        if (isset($response['{DAV:}getetag'])) {
+            $etag = trim($response['{DAV:}getetag'], '"');
+            if (strlen($etag) > 40) {
+                $etag = md5($etag);
+            }
+            return $etag;
+        }
+        return parent::getEtag($path);
+    }
+
+    /**
+     * @param string $permissionsString
+     * @return int
+     */
+    protected function parsePermissions($permissionsString) {
+        $permissions = Constants::PERMISSION_READ;
+        if (strpos($permissionsString, 'R') !== false) {
+            $permissions |= Constants::PERMISSION_SHARE;
+        }
+        if (strpos($permissionsString, 'D') !== false) {
+            $permissions |= Constants::PERMISSION_DELETE;
+        }
+        if (strpos($permissionsString, 'W') !== false) {
+            $permissions |= Constants::PERMISSION_UPDATE;
+        }
+        if (strpos($permissionsString, 'CK') !== false) {
+            $permissions |= Constants::PERMISSION_CREATE;
+            $permissions |= Constants::PERMISSION_UPDATE;
+        }
+        return $permissions;
+    }
+
+    /**
+     * check if a file or folder has been updated since $time
+     *
+     * @param string $path
+     * @param int $time
+     * @throws \OCP\Files\StorageNotAvailableException
+     * @return bool
+     */
+    public function hasUpdated($path, $time) {
+        $this->init();
+        $path = $this->cleanPath($path);
+        try {
+            // force refresh for $path
+            $this->statCache->remove($path);
+            $response = $this->propfind($path);
+            if ($response === false) {
+                if ($path === '') {
+                    // if root is gone it means the storage is not available
+                    throw new StorageNotAvailableException('root is gone');
+                }
+                return false;
+            }
+            if (isset($response['{DAV:}getetag'])) {
+                $cachedData = $this->getCache()->get($path);
+                $etag = null;
+                if (isset($response['{DAV:}getetag'])) {
+                    $etag = trim($response['{DAV:}getetag'], '"');
+                }
+                if (!empty($etag) && $cachedData['etag'] !== $etag) {
+                    return true;
+                } else if (isset($response['{http://open-collaboration-services.org/ns}share-permissions'])) {
+                    $sharePermissions = (int)$response['{http://open-collaboration-services.org/ns}share-permissions'];
+                    return $sharePermissions !== $cachedData['permissions'];
+                } else if (isset($response['{http://owncloud.org/ns}permissions'])) {
+                    $permissions = $this->parsePermissions($response['{http://owncloud.org/ns}permissions']);
+                    return $permissions !== $cachedData['permissions'];
+                } else {
+                    return false;
+                }
+            } else {
+                $remoteMtime = strtotime($response['{DAV:}getlastmodified']);
+                return $remoteMtime > $time;
+            }
+        } catch (ClientHttpException $e) {
+            if ($e->getHttpStatus() === 405) {
+                if ($path === '') {
+                    // if root is gone it means the storage is not available
+                    throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
+                }
+                return false;
+            }
+            $this->convertException($e, $path);
+            return false;
+        } catch (\Exception $e) {
+            $this->convertException($e, $path);
+            return false;
+        }
+    }
+
+    /**
+     * Interpret the given exception and decide whether it is due to an
+     * unavailable storage, invalid storage or other.
+     * This will either throw StorageInvalidException, StorageNotAvailableException
+     * or do nothing.
+     *
+     * @param Exception $e sabre exception
+     * @param string $path optional path from the operation
+     *
+     * @throws StorageInvalidException if the storage is invalid, for example
+     * when the authentication expired or is invalid
+     * @throws StorageNotAvailableException if the storage is not available,
+     * which might be temporary
+     */
+    protected function convertException(Exception $e, $path = '') {
+        \OC::$server->getLogger()->logException($e, ['app' => 'files_external', 'level' => ILogger::DEBUG]);
+        if ($e instanceof ClientHttpException) {
+            if ($e->getHttpStatus() === Http::STATUS_LOCKED) {
+                throw new \OCP\Lock\LockedException($path);
+            }
+            if ($e->getHttpStatus() === Http::STATUS_UNAUTHORIZED) {
+                // either password was changed or was invalid all along
+                throw new StorageInvalidException(get_class($e) . ': ' . $e->getMessage());
+            } else if ($e->getHttpStatus() === Http::STATUS_METHOD_NOT_ALLOWED) {
+                // ignore exception for MethodNotAllowed, false will be returned
+                return;
+            }
+            throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
+        } else if ($e instanceof ClientException) {
+            // connection timeout or refused, server could be temporarily down
+            throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
+        } else if ($e instanceof \InvalidArgumentException) {
+            // parse error because the server returned HTML instead of XML,
+            // possibly temporarily down
+            throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
+        } else if (($e instanceof StorageNotAvailableException) || ($e instanceof StorageInvalidException)) {
+            // rethrow
+            throw $e;
+        }
+
+        // TODO: only log for now, but in the future need to wrap/rethrow exception
+    }
 }