Introduce BackendService for managing external storage backends

Backends are registered to the BackendService through new data
structures:

Backends are concrete classes, deriving from
\OCA\Files_External\Lib\Backend\Backend. During construction, the
various configuration parameters of the Backend can be set, in a design
similar to Symfony Console.

DefinitionParameter stores a parameter configuration for an external
storage: name of parameter, human-readable name, type of parameter
(text, password, hidden, checkbox), flags (optional or not).

Storages in the StoragesController now get their parameters validated
server-side (fixes a TODO).

1 files changed, 63 insertions, 6 deletions

diff --git a/apps/files_external/controller/storagescontroller.php b/apps/files_external/controller/storagescontroller.php
index c09ceacc7d7..c653b51bf89 100644
--- a/apps/files_external/controller/storagescontroller.php
+++ b/apps/files_external/controller/storagescontroller.php
@@ -32,6 +32,7 @@ use \OCP\AppFramework\Http;
 use \OCA\Files_external\Service\StoragesService;
 use \OCA\Files_external\NotFoundException;
 use \OCA\Files_external\Lib\StorageConfig;
+use \OCA\Files_External\Lib\Backend\Backend;
 
 /**
  * Base class for storages controllers
@@ -72,6 +73,48 @@ abstract class StoragesController extends Controller {
 	}
 
 	/**
+	 * Create a storage from its parameters
+	 *
+	 * @param string $mountPoint storage mount point
+	 * @param string $backendClass backend class name
+	 * @param array $backendOptions backend-specific options
+	 * @param array|null $mountOptions mount-specific options
+	 * @param array|null $applicableUsers users for which to mount the storage
+	 * @param array|null $applicableGroups groups for which to mount the storage
+	 * @param int|null $priority priority
+	 *
+	 * @return StorageConfig|DataResponse
+	 */
+	protected function createStorage(
+		$mountPoint,
+		$backendClass,
+		$backendOptions,
+		$mountOptions = null,
+		$applicableUsers = null,
+		$applicableGroups = null,
+		$priority = null
+	) {
+		try {
+			return $this->service->createStorage(
+				$mountPoint,
+				$backendClass,
+				$backendOptions,
+				$mountOptions,
+				$applicableUsers,
+				$applicableGroups,
+				$priority
+			);
+		} catch (\InvalidArgumentException $e) {
+			return new DataResponse(
+				[
+					'message' => (string)$this->l10n->t('Invalid backend class "%s"', [$backendClass])
+				],
+				Http::STATUS_UNPROCESSABLE_ENTITY
+			);
+		}
+	}
+
+	/**
 	 * Validate storage config
 	 *
 	 * @param StorageConfig $storage storage config
@@ -89,14 +132,24 @@ abstract class StoragesController extends Controller {
 			);
 		}
 
-		// TODO: validate that other attrs are set
-
-		$backends = \OC_Mount_Config::getBackends();
-		if (!isset($backends[$storage->getBackendClass()])) {
+		/** @var Backend */
+		$backend = $storage->getBackend();
+		if (!$backend || $backend->checkDependencies()) {
 			// invalid backend
 			return new DataResponse(
 				array(
-					'message' => (string)$this->l10n->t('Invalid storage backend "%s"', array($storage->getBackendClass()))
+					'message' => (string)$this->l10n->t('Invalid storage backend "%s"', [
+						$storage->getBackend()->getClass()
+					])
+				),
+				Http::STATUS_UNPROCESSABLE_ENTITY
+			);
+		}
+		if (!$backend->validateStorage($storage)) {
+			// unsatisfied parameters
+			return new DataResponse(
+				array(
+					'message' => (string)$this->l10n->t('Unsatisfied backend parameters')
 				),
 				Http::STATUS_UNPROCESSABLE_ENTITY
 			);
@@ -114,10 +167,14 @@ abstract class StoragesController extends Controller {
 	 * @param StorageConfig $storage storage configuration
 	 */
 	protected function updateStorageStatus(StorageConfig &$storage) {
+		/** @var Backend */
+		$backend = $storage->getBackend();
+		$backend->manipulateStorageConfig($storage);
+
 		// update status (can be time-consuming)
 		$storage->setStatus(
 			\OC_Mount_Config::getBackendStatus(
-				$storage->getBackendClass(),
+				$storage->getBackend()->getStorageClass(),
 				$storage->getBackendOptions(),
 				false
 			)