feat: Support deleting metadata from WebDAV

The `$value` will be `null` if the update is wrapped inside a `<d:remove>...</d:remove>` block.

Signed-off-by: Louis Chemineau <louis@chmn.me>

apps/dav/lib/Connector/Sabre/FilesPlugin.php

@@ -599,6 +599,12 @@ class FilesPlugin extends ServerPlugin {
 						throw new FilesMetadataException('you do not have enough rights to update \'' . $metadataKey . '\' on this node');
 					}
 
+					if ($value === null) {
+						$metadata->unset($metadataKey);
+						$filesMetadataManager->saveMetadata($metadata);
+						return true;
+					}
+
 					// If the metadata is unknown, it defaults to string.
 					try {
 						$type = $knownMetadata->getType($metadataKey);

build/integration/config/behat.yml

@@ -113,6 +113,12 @@ default:
         - CommandLineContext:
             baseUrl: http://localhost:8080
             ocPath: ../../
+        - MetadataContext:
+            baseUrl: http://localhost:8080
+            admin:
+              - admin
+              - admin
+            regular_user_password: 123456
     files_conversion:
       paths:
         - "%paths.base%/../file_conversions"

build/integration/features/bootstrap/MetadataContext.php

@@ -0,0 +1,123 @@
+<?php
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+use Behat\Behat\Context\Context;
+use Behat\Step\Then;
+use Behat\Step\When;
+use PHPUnit\Framework\Assert;
+use Sabre\DAV\Client as SClient;
+
+require __DIR__ . '/../../vendor/autoload.php';
+
+class MetadataContext implements Context {
+	private string $davPath = '/remote.php/dav';
+
+	public function __construct(
+		private string $baseUrl,
+		private array $admin,
+		private string $regular_user_password,
+	) {
+		// in case of ci deployment we take the server url from the environment
+		$testServerUrl = getenv('TEST_SERVER_URL');
+		if ($testServerUrl !== false) {
+			$this->baseUrl = substr($testServerUrl, 0, -5);
+		}
+	}
+
+	#[When('User :user sets the :metadataKey prop with value :metadataValue on :fileName')]
+	public function userSetsProp(string $user, string $metadataKey, string $metadataValue, string $fileName) {
+		$client = new SClient([
+			'baseUri' => $this->baseUrl,
+			'userName' => $user,
+			'password' => '123456',
+			'authType' => SClient::AUTH_BASIC,
+		]);
+
+		$body = '<?xml version="1.0"?>
+<d:propertyupdate xmlns:d="DAV:" xmlns:nc="http://nextcloud.com/ns">
+  <d:set>
+   <d:prop>
+      <nc:' . $metadataKey . '>' . $metadataValue . '</nc:' . $metadataKey . '>
+    </d:prop>
+  </d:set>
+</d:propertyupdate>';
+
+		$davUrl = $this->getDavUrl($user, $fileName);
+		$client->request('PROPPATCH', $this->baseUrl . $davUrl, $body);
+	}
+
+	#[When('User :user deletes the :metadataKey prop on :fileName')]
+	public function userDeletesProp(string $user, string $metadataKey, string $fileName) {
+		$client = new SClient([
+			'baseUri' => $this->baseUrl,
+			'userName' => $user,
+			'password' => '123456',
+			'authType' => SClient::AUTH_BASIC,
+		]);
+
+		$body = '<?xml version="1.0"?>
+<d:propertyupdate xmlns:d="DAV:" xmlns:nc="http://nextcloud.com/ns">
+  <d:remove>
+   <d:prop>
+      <nc:' . $metadataKey . '></nc:' . $metadataKey . '>
+    </d:prop>
+  </d:remove>
+</d:propertyupdate>';
+
+		$davUrl = $this->getDavUrl($user, $fileName);
+		$client->request('PROPPATCH', $this->baseUrl . $davUrl, $body);
+	}
+
+	#[Then('User :user should see the prop :metadataKey equal to :metadataValue for file :fileName')]
+	public function checkPropForFile(string $user, string $metadataKey, string $metadataValue, string $fileName) {
+		$client = new SClient([
+			'baseUri' => $this->baseUrl,
+			'userName' => $user,
+			'password' => '123456',
+			'authType' => SClient::AUTH_BASIC,
+		]);
+
+		$body = '<?xml version="1.0"?>
+<d:propfind xmlns:d="DAV:" xmlns:nc="http://nextcloud.com/ns">
+   <d:prop>
+      <nc:' . $metadataKey . '></nc:' . $metadataKey . '>
+    </d:prop>
+</d:propfind>';
+
+		$davUrl = $this->getDavUrl($user, $fileName);
+		$response = $client->request('PROPFIND', $this->baseUrl . $davUrl, $body);
+		$parsedResponse = $client->parseMultistatus($response['body']);
+
+		Assert::assertEquals($parsedResponse[$davUrl]['200']['{http://nextcloud.com/ns}' . $metadataKey], $metadataValue);
+	}
+
+	#[Then('User :user should not see the prop :metadataKey for file :fileName')]
+	public function checkPropDoesNotExistsForFile(string $user, string $metadataKey, string $fileName) {
+		$client = new SClient([
+			'baseUri' => $this->baseUrl,
+			'userName' => $user,
+			'password' => '123456',
+			'authType' => SClient::AUTH_BASIC,
+		]);
+
+		$body = '<?xml version="1.0"?>
+<d:propfind xmlns:d="DAV:" xmlns:nc="http://nextcloud.com/ns">
+   <d:prop>
+      <nc:' . $metadataKey . '></nc:' . $metadataKey . '>
+    </d:prop>
+</d:propfind>';
+
+		$davUrl = $this->getDavUrl($user, $fileName);
+		$response = $client->request('PROPFIND', $this->baseUrl . $davUrl, $body);
+		$parsedResponse = $client->parseMultistatus($response['body']);
+
+		Assert::assertEquals($parsedResponse[$davUrl]['404']['{http://nextcloud.com/ns}' . $metadataKey], null);
+	}
+
+	private function getDavUrl(string $user, string $fileName) {
+		return $this->davPath . '/files/' . $user . $fileName;
+	}
+}

build/integration/files_features/metadata.feature

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+# SPDX-License-Identifier: AGPL-3.0-only
+Feature: metadata
+
+  Scenario: Setting metadata works
+    Given user "user0" exists
+    When User "user0" uploads file with content "AAA" to "/test.txt"
+    And User "user0" sets the "metadata-files-live-photo" prop with value "metadata-value" on "/test.txt"
+    Then User "user0" should see the prop "metadata-files-live-photo" equal to "metadata-value" for file "/test.txt"
+
+  Scenario: Deleting metadata works
+    Given user "user0" exists
+    When User "user0" uploads file with content "AAA" to "/test.txt"
+    And User "user0" sets the "metadata-files-live-photo" prop with value "metadata-value" on "/test.txt"
+	  And User "user0" deletes the "metadata-files-live-photo" prop on "/test.txt"
+	  Then User "user0" should not see the prop "metadata-files-live-photo" for file "/test.txt"