Merge pull request #48721 from nextcloud/feat/allow-getter-setter-decl-fors

12 files changed, 183 insertions, 120 deletions

diff --git a/apps/files/composer/composer/autoload_classmap.php b/apps/files/composer/composer/autoload_classmap.php
index 4be3f54c006..e9e45bbd84a 100644
--- a/apps/files/composer/composer/autoload_classmap.php
+++ b/apps/files/composer/composer/autoload_classmap.php
@@ -58,9 +58,6 @@ return array(
     'OCA\\Files\\Event\\LoadSidebar' => $baseDir . '/../lib/Event/LoadSidebar.php',
     'OCA\\Files\\Exception\\TransferOwnershipException' => $baseDir . '/../lib/Exception/TransferOwnershipException.php',
     'OCA\\Files\\Helper' => $baseDir . '/../lib/Helper.php',
-    'OCA\\Files\\Listener\\DeclarativeSettingsGetValueEventListener' => $baseDir . '/../lib/Listener/DeclarativeSettingsGetValueEventListener.php',
-    'OCA\\Files\\Listener\\DeclarativeSettingsRegisterFormEventListener' => $baseDir . '/../lib/Listener/DeclarativeSettingsRegisterFormEventListener.php',
-    'OCA\\Files\\Listener\\DeclarativeSettingsSetValueEventListener' => $baseDir . '/../lib/Listener/DeclarativeSettingsSetValueEventListener.php',
     'OCA\\Files\\Listener\\LoadSearchPluginsListener' => $baseDir . '/../lib/Listener/LoadSearchPluginsListener.php',
     'OCA\\Files\\Listener\\LoadSidebarListener' => $baseDir . '/../lib/Listener/LoadSidebarListener.php',
     'OCA\\Files\\Listener\\RenderReferenceEventListener' => $baseDir . '/../lib/Listener/RenderReferenceEventListener.php',
@@ -79,5 +76,6 @@ return array(
     'OCA\\Files\\Service\\TagService' => $baseDir . '/../lib/Service/TagService.php',
     'OCA\\Files\\Service\\UserConfig' => $baseDir . '/../lib/Service/UserConfig.php',
     'OCA\\Files\\Service\\ViewConfig' => $baseDir . '/../lib/Service/ViewConfig.php',
+    'OCA\\Files\\Settings\\DeclarativeAdminSettings' => $baseDir . '/../lib/Settings/DeclarativeAdminSettings.php',
     'OCA\\Files\\Settings\\PersonalSettings' => $baseDir . '/../lib/Settings/PersonalSettings.php',
 );
diff --git a/apps/files/composer/composer/autoload_static.php b/apps/files/composer/composer/autoload_static.php
index 292768fc64f..59695e60fc7 100644
--- a/apps/files/composer/composer/autoload_static.php
+++ b/apps/files/composer/composer/autoload_static.php
@@ -73,9 +73,6 @@ class ComposerStaticInitFiles
         'OCA\\Files\\Event\\LoadSidebar' => __DIR__ . '/..' . '/../lib/Event/LoadSidebar.php',
         'OCA\\Files\\Exception\\TransferOwnershipException' => __DIR__ . '/..' . '/../lib/Exception/TransferOwnershipException.php',
         'OCA\\Files\\Helper' => __DIR__ . '/..' . '/../lib/Helper.php',
-        'OCA\\Files\\Listener\\DeclarativeSettingsGetValueEventListener' => __DIR__ . '/..' . '/../lib/Listener/DeclarativeSettingsGetValueEventListener.php',
-        'OCA\\Files\\Listener\\DeclarativeSettingsRegisterFormEventListener' => __DIR__ . '/..' . '/../lib/Listener/DeclarativeSettingsRegisterFormEventListener.php',
-        'OCA\\Files\\Listener\\DeclarativeSettingsSetValueEventListener' => __DIR__ . '/..' . '/../lib/Listener/DeclarativeSettingsSetValueEventListener.php',
         'OCA\\Files\\Listener\\LoadSearchPluginsListener' => __DIR__ . '/..' . '/../lib/Listener/LoadSearchPluginsListener.php',
         'OCA\\Files\\Listener\\LoadSidebarListener' => __DIR__ . '/..' . '/../lib/Listener/LoadSidebarListener.php',
         'OCA\\Files\\Listener\\RenderReferenceEventListener' => __DIR__ . '/..' . '/../lib/Listener/RenderReferenceEventListener.php',
@@ -94,6 +91,7 @@ class ComposerStaticInitFiles
         'OCA\\Files\\Service\\TagService' => __DIR__ . '/..' . '/../lib/Service/TagService.php',
         'OCA\\Files\\Service\\UserConfig' => __DIR__ . '/..' . '/../lib/Service/UserConfig.php',
         'OCA\\Files\\Service\\ViewConfig' => __DIR__ . '/..' . '/../lib/Service/ViewConfig.php',
+        'OCA\\Files\\Settings\\DeclarativeAdminSettings' => __DIR__ . '/..' . '/../lib/Settings/DeclarativeAdminSettings.php',
         'OCA\\Files\\Settings\\PersonalSettings' => __DIR__ . '/..' . '/../lib/Settings/PersonalSettings.php',
     );
 
diff --git a/apps/files/lib/AppInfo/Application.php b/apps/files/lib/AppInfo/Application.php
index 3d2d0527072..d50a8d14f5a 100644
--- a/apps/files/lib/AppInfo/Application.php
+++ b/apps/files/lib/AppInfo/Application.php
@@ -16,9 +16,6 @@ use OCA\Files\Controller\ApiController;
 use OCA\Files\DirectEditingCapabilities;
 use OCA\Files\Event\LoadSearchPlugins;
 use OCA\Files\Event\LoadSidebar;
-use OCA\Files\Listener\DeclarativeSettingsGetValueEventListener;
-use OCA\Files\Listener\DeclarativeSettingsRegisterFormEventListener;
-use OCA\Files\Listener\DeclarativeSettingsSetValueEventListener;
 use OCA\Files\Listener\LoadSearchPluginsListener;
 use OCA\Files\Listener\LoadSidebarListener;
 use OCA\Files\Listener\RenderReferenceEventListener;
@@ -28,6 +25,7 @@ use OCA\Files\Search\FilesSearchProvider;
 use OCA\Files\Service\TagService;
 use OCA\Files\Service\UserConfig;
 use OCA\Files\Service\ViewConfig;
+use OCA\Files\Settings\DeclarativeAdminSettings;
 use OCP\Activity\IManager as IActivityManager;
 use OCP\AppFramework\App;
 use OCP\AppFramework\Bootstrap\IBootContext;
@@ -49,9 +47,6 @@ use OCP\IRequest;
 use OCP\IServerContainer;
 use OCP\ITagManager;
 use OCP\IUserSession;
-use OCP\Settings\Events\DeclarativeSettingsGetValueEvent;
-use OCP\Settings\Events\DeclarativeSettingsRegisterFormEvent;
-use OCP\Settings\Events\DeclarativeSettingsSetValueEvent;
 use OCP\Share\IManager as IShareManager;
 use OCP\Util;
 use Psr\Container\ContainerInterface;
@@ -111,6 +106,8 @@ class Application extends App implements IBootstrap {
 		$context->registerCapability(Capabilities::class);
 		$context->registerCapability(DirectEditingCapabilities::class);
 
+		$context->registerDeclarativeSettings(DeclarativeAdminSettings::class);
+
 		$context->registerEventListener(LoadSidebar::class, LoadSidebarListener::class);
 		$context->registerEventListener(RenderReferenceEvent::class, RenderReferenceEventListener::class);
 		$context->registerEventListener(BeforeNodeRenamedEvent::class, SyncLivePhotosListener::class);
@@ -119,9 +116,6 @@ class Application extends App implements IBootstrap {
 		$context->registerEventListener(BeforeNodeCopiedEvent::class, SyncLivePhotosListener::class);
 		$context->registerEventListener(NodeCopiedEvent::class, SyncLivePhotosListener::class);
 		$context->registerEventListener(LoadSearchPlugins::class, LoadSearchPluginsListener::class);
-		$context->registerEventListener(DeclarativeSettingsRegisterFormEvent::class, DeclarativeSettingsRegisterFormEventListener::class);
-		$context->registerEventListener(DeclarativeSettingsGetValueEvent::class, DeclarativeSettingsGetValueEventListener::class);
-		$context->registerEventListener(DeclarativeSettingsSetValueEvent::class, DeclarativeSettingsSetValueEventListener::class);
 
 		$context->registerSearchProvider(FilesSearchProvider::class);
 
diff --git a/apps/files/lib/Listener/DeclarativeSettingsGetValueEventListener.php b/apps/files/lib/Listener/DeclarativeSettingsGetValueEventListener.php
deleted file mode 100644
index b1d0ee3a395..00000000000
--- a/apps/files/lib/Listener/DeclarativeSettingsGetValueEventListener.php
+++ /dev/null
@@ -1,39 +0,0 @@
-<?php
-
-declare(strict_types=1);
-/**
- * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
- * SPDX-License-Identifier: AGPL-3.0-or-later
- */
-namespace OCA\Files\Listener;
-
-use OCA\Files\AppInfo\Application;
-use OCA\Files\Service\SettingsService;
-use OCP\EventDispatcher\Event;
-use OCP\EventDispatcher\IEventListener;
-use OCP\Settings\Events\DeclarativeSettingsGetValueEvent;
-
-/** @template-implements IEventListener<DeclarativeSettingsGetValueEvent> */
-class DeclarativeSettingsGetValueEventListener implements IEventListener {
-
-	public function __construct(
-		private SettingsService $service,
-	) {
-	}
-
-	public function handle(Event $event): void {
-		if (!($event instanceof DeclarativeSettingsGetValueEvent)) {
-			return;
-		}
-
-		if ($event->getApp() !== Application::APP_ID) {
-			return;
-		}
-
-		$event->setValue(
-			match($event->getFieldId()) {
-				'windows_support' => $this->service->hasFilesWindowsSupport(),
-			}
-		);
-	}
-}
diff --git a/apps/files/lib/Listener/DeclarativeSettingsSetValueEventListener.php b/apps/files/lib/Listener/DeclarativeSettingsSetValueEventListener.php
deleted file mode 100644
index a3be2b9141e..00000000000
--- a/apps/files/lib/Listener/DeclarativeSettingsSetValueEventListener.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-
-declare(strict_types=1);
-/**
- * SPDX-FileCopyrightText: 2016 Nextcloud GmbH and Nextcloud contributors
- * SPDX-License-Identifier: AGPL-3.0-or-later
- */
-namespace OCA\Files\Listener;
-
-use OCA\Files\AppInfo\Application;
-use OCA\Files\Service\SettingsService;
-use OCP\EventDispatcher\Event;
-use OCP\EventDispatcher\IEventListener;
-use OCP\Settings\Events\DeclarativeSettingsSetValueEvent;
-
-/** @template-implements IEventListener<DeclarativeSettingsSetValueEvent> */
-class DeclarativeSettingsSetValueEventListener implements IEventListener {
-
-	public function __construct(
-		private SettingsService $service,
-	) {
-	}
-
-	public function handle(Event $event): void {
-		if (!($event instanceof DeclarativeSettingsSetValueEvent)) {
-			return;
-		}
-
-		if ($event->getApp() !== Application::APP_ID) {
-			return;
-		}
-
-		switch ($event->getFieldId()) {
-			case 'windows_support':
-				$this->service->setFilesWindowsSupport((bool)$event->getValue());
-				$event->stopPropagation();
-				break;
-		}
-	}
-}
diff --git a/apps/files/lib/Listener/DeclarativeSettingsRegisterFormEventListener.php b/apps/files/lib/Settings/DeclarativeAdminSettings.php
index 51832e89ecb..e509ad2233b 100644
--- a/apps/files/lib/Listener/DeclarativeSettingsRegisterFormEventListener.php
+++ b/apps/files/lib/Settings/DeclarativeAdminSettings.php
@@ -2,32 +2,42 @@
 
 declare(strict_types=1);
 /**
- * SPDX-FileCopyrightText: 2016 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
  * SPDX-License-Identifier: AGPL-3.0-or-later
  */
-namespace OCA\Files\Listener;
+namespace OCA\Files\Settings;
 
-use OCA\Files\AppInfo\Application;
-use OCP\EventDispatcher\Event;
-use OCP\EventDispatcher\IEventListener;
+use OCA\Files\Service\SettingsService;
 use OCP\IL10N;
+use OCP\IUser;
 use OCP\Settings\DeclarativeSettingsTypes;
-use OCP\Settings\Events\DeclarativeSettingsRegisterFormEvent;
+use OCP\Settings\IDeclarativeSettingsFormWithHandlers;
 
-/** @template-implements IEventListener<DeclarativeSettingsRegisterFormEvent> */
-class DeclarativeSettingsRegisterFormEventListener implements IEventListener {
+class DeclarativeAdminSettings implements IDeclarativeSettingsFormWithHandlers {
 
 	public function __construct(
 		private IL10N $l,
+		private SettingsService $service,
 	) {
 	}
 
-	public function handle(Event $event): void {
-		if (!($event instanceof DeclarativeSettingsRegisterFormEvent)) {
-			return;
+	public function getValue(string $fieldId, IUser $user): mixed {
+		return match($fieldId) {
+			'windows_support' => $this->service->hasFilesWindowsSupport(),
+			default => throw new \InvalidArgumentException('Unexpected field id ' . $fieldId),
+		};
+	}
+
+	public function setValue(string $fieldId, mixed $value, IUser $user): void {
+		switch ($fieldId) {
+			case 'windows_support':
+				$this->service->setFilesWindowsSupport((bool)$value);
+				break;
 		}
+	}
 
-		$event->registerSchema(Application::APP_ID, [
+	public function getSchema(): array {
+		return [
 			'id' => 'files-filename-support',
 			'priority' => 10,
 			'section_type' => DeclarativeSettingsTypes::SECTION_TYPE_ADMIN,
@@ -45,6 +55,6 @@ class DeclarativeSettingsRegisterFormEventListener implements IEventListener {
 					'default' => false,
 				],
 			],
-		]);
+		];
 	}
 }
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index ef9af33414f..7265edfe95f 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -698,6 +698,7 @@ return array(
     'OCP\\Settings\\Events\\DeclarativeSettingsSetValueEvent' => $baseDir . '/lib/public/Settings/Events/DeclarativeSettingsSetValueEvent.php',
     'OCP\\Settings\\IDeclarativeManager' => $baseDir . '/lib/public/Settings/IDeclarativeManager.php',
     'OCP\\Settings\\IDeclarativeSettingsForm' => $baseDir . '/lib/public/Settings/IDeclarativeSettingsForm.php',
+    'OCP\\Settings\\IDeclarativeSettingsFormWithHandlers' => $baseDir . '/lib/public/Settings/IDeclarativeSettingsFormWithHandlers.php',
     'OCP\\Settings\\IDelegatedSettings' => $baseDir . '/lib/public/Settings/IDelegatedSettings.php',
     'OCP\\Settings\\IIconSection' => $baseDir . '/lib/public/Settings/IIconSection.php',
     'OCP\\Settings\\IManager' => $baseDir . '/lib/public/Settings/IManager.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index 99f8afb61f1..4bac34425ac 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -731,6 +731,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\Settings\\Events\\DeclarativeSettingsSetValueEvent' => __DIR__ . '/../../..' . '/lib/public/Settings/Events/DeclarativeSettingsSetValueEvent.php',
         'OCP\\Settings\\IDeclarativeManager' => __DIR__ . '/../../..' . '/lib/public/Settings/IDeclarativeManager.php',
         'OCP\\Settings\\IDeclarativeSettingsForm' => __DIR__ . '/../../..' . '/lib/public/Settings/IDeclarativeSettingsForm.php',
+        'OCP\\Settings\\IDeclarativeSettingsFormWithHandlers' => __DIR__ . '/../../..' . '/lib/public/Settings/IDeclarativeSettingsFormWithHandlers.php',
         'OCP\\Settings\\IDelegatedSettings' => __DIR__ . '/../../..' . '/lib/public/Settings/IDelegatedSettings.php',
         'OCP\\Settings\\IIconSection' => __DIR__ . '/../../..' . '/lib/public/Settings/IIconSection.php',
         'OCP\\Settings\\IManager' => __DIR__ . '/../../..' . '/lib/public/Settings/IManager.php',
diff --git a/lib/private/Settings/DeclarativeManager.php b/lib/private/Settings/DeclarativeManager.php
index d8c25c9a5c7..dea0c678f20 100644
--- a/lib/private/Settings/DeclarativeManager.php
+++ b/lib/private/Settings/DeclarativeManager.php
@@ -22,6 +22,7 @@ use OCP\Settings\Events\DeclarativeSettingsRegisterFormEvent;
 use OCP\Settings\Events\DeclarativeSettingsSetValueEvent;
 use OCP\Settings\IDeclarativeManager;
 use OCP\Settings\IDeclarativeSettingsForm;
+use OCP\Settings\IDeclarativeSettingsFormWithHandlers;
 use Psr\Log\LoggerInterface;
 
 /**
@@ -32,6 +33,15 @@ use Psr\Log\LoggerInterface;
  * @psalm-import-type DeclarativeSettingsFormSchemaWithoutValues from IDeclarativeSettingsForm
  */
 class DeclarativeManager implements IDeclarativeManager {
+
+	/** @var array<string, list<IDeclarativeSettingsForm>> */
+	private array $declarativeForms = [];
+
+	/**
+	 * @var array<string, list<DeclarativeSettingsFormSchemaWithoutValues>>
+	 */
+	private array $appSchemas = [];
+
 	public function __construct(
 		private IEventDispatcher $eventDispatcher,
 		private IGroupManager $groupManager,
@@ -43,11 +53,6 @@ class DeclarativeManager implements IDeclarativeManager {
 	}
 
 	/**
-	 * @var array<string, list<DeclarativeSettingsFormSchemaWithoutValues>>
-	 */
-	private array $appSchemas = [];
-
-	/**
 	 * @inheritdoc
 	 */
 	public function registerSchema(string $app, array $schema): void {
@@ -77,11 +82,15 @@ class DeclarativeManager implements IDeclarativeManager {
 	 * @inheritdoc
 	 */
 	public function loadSchemas(): void {
-		$declarativeSettings = $this->coordinator->getRegistrationContext()->getDeclarativeSettings();
-		foreach ($declarativeSettings as $declarativeSetting) {
-			/** @var IDeclarativeSettingsForm $declarativeSettingObject */
-			$declarativeSettingObject = Server::get($declarativeSetting->getService());
-			$this->registerSchema($declarativeSetting->getAppId(), $declarativeSettingObject->getSchema());
+		if (empty($this->declarativeForms)) {
+			$declarativeSettings = $this->coordinator->getRegistrationContext()->getDeclarativeSettings();
+			foreach ($declarativeSettings as $declarativeSetting) {
+				$app = $declarativeSetting->getAppId();
+				/** @var IDeclarativeSettingsForm $declarativeForm */
+				$declarativeForm = Server::get($declarativeSetting->getService());
+				$this->registerSchema($app, $declarativeForm->getSchema());
+				$this->declarativeForms[$app][] = $declarativeForm;
+			}
 		}
 
 		$this->eventDispatcher->dispatchTyped(new DeclarativeSettingsRegisterFormEvent($this));
@@ -224,6 +233,10 @@ class DeclarativeManager implements IDeclarativeManager {
 		$storageType = $this->getStorageType($app, $fieldId);
 		switch ($storageType) {
 			case DeclarativeSettingsTypes::STORAGE_TYPE_EXTERNAL:
+				$form = $this->getForm($app, $formId);
+				if ($form !== null && $form instanceof IDeclarativeSettingsFormWithHandlers) {
+					return $form->getValue($fieldId, $user);
+				}
 				$event = new DeclarativeSettingsGetValueEvent($user, $app, $formId, $fieldId);
 				$this->eventDispatcher->dispatchTyped($event);
 				return $event->getValue();
@@ -244,6 +257,12 @@ class DeclarativeManager implements IDeclarativeManager {
 		$storageType = $this->getStorageType($app, $fieldId);
 		switch ($storageType) {
 			case DeclarativeSettingsTypes::STORAGE_TYPE_EXTERNAL:
+				$form = $this->getForm($app, $formId);
+				if ($form !== null && $form instanceof IDeclarativeSettingsFormWithHandlers) {
+					$form->setValue($fieldId, $value, $user);
+					break;
+				}
+				// fall back to event handling
 				$this->eventDispatcher->dispatchTyped(new DeclarativeSettingsSetValueEvent($user, $app, $formId, $fieldId, $value));
 				break;
 			case DeclarativeSettingsTypes::STORAGE_TYPE_INTERNAL:
@@ -254,6 +273,20 @@ class DeclarativeManager implements IDeclarativeManager {
 		}
 	}
 
+	/**
+	 * If a declarative setting was registered as a form and not just a schema
+	 * then this will yield the registering form.
+	 */
+	private function getForm(string $app, string $formId): ?IDeclarativeSettingsForm {
+		$allForms = $this->declarativeForms[$app] ?? [];
+		foreach ($allForms as $form) {
+			if ($form->getSchema()['id'] === $formId) {
+				return $form;
+			}
+		}
+		return null;
+	}
+
 	private function getInternalValue(IUser $user, string $app, string $formId, string $fieldId): mixed {
 		$sectionType = $this->getSectionType($app, $fieldId);
 		$defaultValue = $this->getDefaultValue($app, $formId, $fieldId);
diff --git a/lib/public/Settings/DeclarativeSettingsTypes.php b/lib/public/Settings/DeclarativeSettingsTypes.php
index 82444af9b82..7edf0cbdd6e 100644
--- a/lib/public/Settings/DeclarativeSettingsTypes.php
+++ b/lib/public/Settings/DeclarativeSettingsTypes.php
@@ -32,8 +32,9 @@ final class DeclarativeSettingsTypes {
 	/**
 	 * IDeclarativeSettingsForm storage_type which is determines where and how the config value is stored
 	 *
-	 *
-	 * For `external` storage_type the app implementing \OCP\Settings\SetDeclarativeSettingsValueEvent and \OCP\Settings\GetDeclarativeSettingsValueEvent events is responsible for storing and retrieving the config value.
+	 * For `external` storage_type the app needs to either implement event listeners for \OCP\Settings\SetDeclarativeSettingsValueEvent
+	 * and \OCP\Settings\GetDeclarativeSettingsValueEvent or the IDeclarativeSettingsForm also needs to implement
+	 * IDeclarativeSettingsFormWithHandlers for storing and retrieving the config value.
 	 *
 	 * @since 29.0.0
 	 */
@@ -43,7 +44,6 @@ final class DeclarativeSettingsTypes {
 	 * IDeclarativeSettingsForm storage_type which is determines where and how the config value is stored
 	 *
 	 * For `internal` storage_type the config value is stored in default `appconfig` and `preferences` tables.
-	 * For `external` storage_type the app implementing \OCP\Settings\SetDeclarativeSettingsValueEvent and \OCP\Settings\GetDeclarativeSettingsValueEvent events is responsible for storing and retrieving the config value.
 	 *
 	 * @since 29.0.0
 	 */
diff --git a/lib/public/Settings/IDeclarativeSettingsFormWithHandlers.php b/lib/public/Settings/IDeclarativeSettingsFormWithHandlers.php
new file mode 100644
index 00000000000..180df73d995
--- /dev/null
+++ b/lib/public/Settings/IDeclarativeSettingsFormWithHandlers.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Settings;
+
+use OCP\IUser;
+
+/**
+ * @since 31.0.0
+ */
+interface IDeclarativeSettingsFormWithHandlers extends IDeclarativeSettingsForm {
+
+	/**
+	 * This function is called to get the current value of a specific forms field.
+	 * @since 31.0.0
+	 */
+	public function getValue(string $fieldId, IUser $user): mixed;
+
+	/**
+	 * This function is called when a user updated a form field to persist the setting.
+	 * @since 31.0.0
+	 */
+	public function setValue(string $fieldId, mixed $value, IUser $user): void;
+
+}
diff --git a/tests/lib/Settings/DeclarativeManagerTest.php b/tests/lib/Settings/DeclarativeManagerTest.php
index f0d97c7ea25..522264acd8c 100644
--- a/tests/lib/Settings/DeclarativeManagerTest.php
+++ b/tests/lib/Settings/DeclarativeManagerTest.php
@@ -10,6 +10,8 @@ declare(strict_types=1);
 namespace Test\Settings;
 
 use OC\AppFramework\Bootstrap\Coordinator;
+use OC\AppFramework\Bootstrap\RegistrationContext;
+use OC\AppFramework\Bootstrap\ServiceRegistration;
 use OC\Settings\DeclarativeManager;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\IAppConfig;
@@ -19,6 +21,8 @@ use OCP\IUser;
 use OCP\Settings\DeclarativeSettingsTypes;
 use OCP\Settings\Events\DeclarativeSettingsSetValueEvent;
 use OCP\Settings\IDeclarativeManager;
+use OCP\Settings\IDeclarativeSettingsForm;
+use OCP\Settings\IDeclarativeSettingsFormWithHandlers;
 use PHPUnit\Framework\MockObject\MockObject;
 use Psr\Log\LoggerInterface;
 use Test\TestCase;
@@ -52,6 +56,8 @@ class DeclarativeManagerTest extends TestCase {
 	/** @var IUser|MockObject */
 	private $adminUser;
 
+	private IDeclarativeSettingsForm&MockObject $closureForm;
+
 	public const validSchemaAllFields = [
 		'id' => 'test_form_1',
 		'priority' => 10,
@@ -518,4 +524,74 @@ class DeclarativeManagerTest extends TestCase {
 		$this->expectException(\Exception::class);
 		$this->declarativeManager->getFormsWithValues($this->user, $schema['section_type'], $schema['section_id']);
 	}
+
+	/**
+	 * Ensure that the `setValue` method is called if the form implements the handler interface.
+	 */
+	public function testSetValueWithHandler(): void {
+		$schema = self::validSchemaAllFields;
+		$schema['storage_type'] = DeclarativeSettingsTypes::STORAGE_TYPE_EXTERNAL;
+
+		$form = $this->createMock(IDeclarativeSettingsFormWithHandlers::class);
+		$form->expects(self::atLeastOnce())
+			->method('getSchema')
+			->willReturn($schema);
+		// The setter should be called once!
+		$form->expects(self::once())
+			->method('setValue')
+			->with('test_field_2', 'some password', $this->adminUser);
+
+		\OC::$server->registerService('OCA\\Testing\\Settings\\DeclarativeForm', fn () => $form, false);
+
+		$context = $this->createMock(RegistrationContext::class);
+		$context->expects(self::atLeastOnce())
+			->method('getDeclarativeSettings')
+			->willReturn([new ServiceRegistration('testing', 'OCA\\Testing\\Settings\\DeclarativeForm')]);
+
+		$this->coordinator->expects(self::atLeastOnce())
+			->method('getRegistrationContext')
+			->willReturn($context);
+
+		$this->declarativeManager->loadSchemas();
+
+		$this->eventDispatcher->expects(self::never())
+			->method('dispatchTyped');
+
+		$this->declarativeManager->setValue($this->adminUser, 'testing', 'test_form_1', 'test_field_2', 'some password');
+	}
+
+	public function testGetValueWithHandler(): void {
+		$schema = self::validSchemaAllFields;
+		$schema['storage_type'] = DeclarativeSettingsTypes::STORAGE_TYPE_EXTERNAL;
+
+		$form = $this->createMock(IDeclarativeSettingsFormWithHandlers::class);
+		$form->expects(self::atLeastOnce())
+			->method('getSchema')
+			->willReturn($schema);
+		// The setter should be called once!
+		$form->expects(self::once())
+			->method('getValue')
+			->with('test_field_2', $this->adminUser)
+			->willReturn('very secret password');
+
+		\OC::$server->registerService('OCA\\Testing\\Settings\\DeclarativeForm', fn () => $form, false);
+
+		$context = $this->createMock(RegistrationContext::class);
+		$context->expects(self::atLeastOnce())
+			->method('getDeclarativeSettings')
+			->willReturn([new ServiceRegistration('testing', 'OCA\\Testing\\Settings\\DeclarativeForm')]);
+
+		$this->coordinator->expects(self::atLeastOnce())
+			->method('getRegistrationContext')
+			->willReturn($context);
+
+		$this->declarativeManager->loadSchemas();
+
+		$this->eventDispatcher->expects(self::never())
+			->method('dispatchTyped');
+
+		$password = $this->invokePrivate($this->declarativeManager, 'getValue', [$this->adminUser, 'testing', 'test_form_1', 'test_field_2']);
+		self::assertEquals('very secret password', $password);
+	}
+
 }