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, 147 insertions, 0 deletions

diff --git a/apps/files_external/lib/frontenddefinitiontrait.php b/apps/files_external/lib/frontenddefinitiontrait.php
new file mode 100644
index 00000000000..4b826372d2f
--- /dev/null
+++ b/apps/files_external/lib/frontenddefinitiontrait.php
@@ -0,0 +1,147 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\Files_External\Lib;
+
+use \OCA\Files_External\Lib\DefinitionParameter;
+use \OCA\Files_External\Lib\StorageConfig;
+
+/**
+ * Trait for objects that have a frontend representation
+ */
+trait FrontendDefinitionTrait {
+
+	/** @var string human-readable mechanism name */
+	private $text;
+
+	/** @var DefinitionParameter[] parameters for mechanism */
+	private $parameters = [];
+
+	/** @var string|null custom JS */
+	private $customJs = null;
+
+	/**
+	 * @return string
+	 */
+	public function getText() {
+		return $this->text;
+	}
+
+	/**
+	 * @param string $text
+	 * @return self
+	 */
+	public function setText($text) {
+		$this->text = $text;
+		return $this;
+	}
+
+	/**
+	 * @param FrontendDefinitionTrait $a
+	 * @param FrontendDefinitionTrait $b
+	 * @return int
+	 */
+	public static function lexicalCompare(FrontendDefinitionTrait $a, FrontendDefinitionTrait $b) {
+		return strcmp($a->getText(), $b->getText());
+	}
+
+	/**
+	 * @return DefinitionParameter[]
+	 */
+	public function getParameters() {
+		return $this->parameters;
+	}
+
+	/**
+	 * @param DefinitionParameter[] $parameters
+	 * @return self
+	 */
+	public function addParameters(array $parameters) {
+		foreach ($parameters as $parameter) {
+			$this->addParameter($parameter);
+		}
+		return $this;
+	}
+
+	/**
+	 * @param DefinitionParameter $parameter
+	 * @return self
+	 */
+	public function addParameter(DefinitionParameter $parameter) {
+		$this->parameters[$parameter->getName()] = $parameter;
+		return $this;
+	}
+
+	/**
+	 * @return string|null
+	 */
+	public function getCustomJs() {
+		return $this->customJs;
+	}
+
+	/**
+	 * @param string $custom
+	 * @return self
+	 */
+	public function setCustomJs($custom) {
+		$this->customJs = $custom;
+		return $this;
+	}
+
+	/**
+	 * Serialize into JSON for client-side JS
+	 *
+	 * @return array
+	 */
+	public function jsonSerializeDefinition() {
+		$configuration = [];
+		foreach ($this->getParameters() as $parameter) {
+			$configuration[$parameter->getName()] = $parameter;
+		}
+
+		$data = [
+			'name' => $this->getText(),
+			'configuration' => $configuration,
+		];
+		if (isset($this->customJs)) {
+			$data['custom'] = $this->getCustomJs();
+		}
+		return $data;
+	}
+
+	/**
+	 * Check if parameters are satisfied in a StorageConfig
+	 *
+	 * @param StorageConfig $storage
+	 * @return bool
+	 */
+	public function validateStorageDefinition(StorageConfig $storage) {
+		$options = $storage->getBackendOptions();
+		foreach ($this->getParameters() as $name => $parameter) {
+			$value = isset($options[$name]) ? $options[$name] : null;
+			if (!$parameter->validateValue($value)) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+}