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diff --git a/apps/files_external/lib/Lib/Backend/Backend.php b/apps/files_external/lib/Lib/Backend/Backend.php
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+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2017-2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+namespace OCA\Files_External\Lib\Backend;
+
+use OCA\Files_External\Lib\Auth\AuthMechanism;
+use OCA\Files_External\Lib\DependencyTrait;
+use OCA\Files_External\Lib\FrontendDefinitionTrait;
+use OCA\Files_External\Lib\IdentifierTrait;
+use OCA\Files_External\Lib\IFrontendDefinition;
+use OCA\Files_External\Lib\IIdentifier;
+use OCA\Files_External\Lib\PriorityTrait;
+use OCA\Files_External\Lib\StorageConfig;
+use OCA\Files_External\Lib\StorageModifierTrait;
+use OCA\Files_External\Lib\VisibilityTrait;
+use OCP\Files\Storage\IStorage;
+
+/**
+ * Storage backend
+ *
+ * A backend can have services injected during construction,
+ * such as \OCP\IDB for database operations. This allows a backend
+ * to perform advanced operations based on provided information.
+ *
+ * An authentication scheme defines the parameter interface, common to the
+ * storage implementation, the backend and the authentication mechanism.
+ * A storage implementation expects parameters according to the authentication
+ * scheme, which are provided from the authentication mechanism.
+ *
+ * This class uses the following traits:
+ *  - VisibilityTrait
+ *      Restrict usage to admin-only/none
+ *  - FrontendDefinitionTrait
+ *      Specify configuration parameters and other definitions
+ *  - PriorityTrait
+ *      Allow objects to prioritize over others with the same mountpoint
+ *  - DependencyTrait
+ *      The object requires certain dependencies to be met
+ *  - StorageModifierTrait
+ *      Object can affect storage mounting
+ */
+class Backend implements \JsonSerializable, IIdentifier, IFrontendDefinition {
+	use VisibilityTrait;
+	use FrontendDefinitionTrait;
+	use PriorityTrait;
+	use DependencyTrait;
+	use StorageModifierTrait;
+	use IdentifierTrait;
+
+	/** @var string storage class */
+	private $storageClass;
+
+	/** @var array 'scheme' => true, supported authentication schemes */
+	private $authSchemes = [];
+
+	/** @var AuthMechanism|callable authentication mechanism fallback */
+	private $legacyAuthMechanism;
+
+	/**
+	 * @return class-string<IStorage>
+	 */
+	public function getStorageClass() {
+		return $this->storageClass;
+	}
+
+	/**
+	 * @param string $class
+	 * @return $this
+	 */
+	public function setStorageClass($class) {
+		$this->storageClass = $class;
+		return $this;
+	}
+
+	/**
+	 * @return array
+	 */
+	public function getAuthSchemes() {
+		if (empty($this->authSchemes)) {
+			return [AuthMechanism::SCHEME_NULL => true];
+		}
+		return $this->authSchemes;
+	}
+
+	/**
+	 * @param string $scheme
+	 * @return self
+	 */
+	public function addAuthScheme($scheme) {
+		$this->authSchemes[$scheme] = true;
+		return $this;
+	}
+
+	/**
+	 * @param array $parameters storage parameters, for dynamic mechanism selection
+	 * @return AuthMechanism
+	 */
+	public function getLegacyAuthMechanism(array $parameters = []) {
+		if (is_callable($this->legacyAuthMechanism)) {
+			return call_user_func($this->legacyAuthMechanism, $parameters);
+		}
+		return $this->legacyAuthMechanism;
+	}
+
+	public function setLegacyAuthMechanism(AuthMechanism $authMechanism): self {
+		$this->legacyAuthMechanism = $authMechanism;
+		return $this;
+	}
+
+	/**
+	 * @param callable $callback dynamic auth mechanism selection
+	 */
+	public function setLegacyAuthMechanismCallback(callable $callback): self {
+		$this->legacyAuthMechanism = $callback;
+		return $this;
+	}
+
+	/**
+	 * Serialize into JSON for client-side JS
+	 */
+	public function jsonSerialize(): array {
+		$data = $this->jsonSerializeDefinition();
+		$data += $this->jsonSerializeIdentifier();
+
+		$data['backend'] = $data['name']; // legacy compat
+		$data['priority'] = $this->getPriority();
+		$data['authSchemes'] = $this->getAuthSchemes();
+
+		return $data;
+	}
+
+	/**
+	 * Check if parameters are satisfied in a StorageConfig
+	 *
+	 * @param StorageConfig $storage
+	 * @return bool
+	 */
+	public function validateStorage(StorageConfig $storage) {
+		return $this->validateStorageDefinition($storage);
+	}
+}