feat(OCM): Make it possible to have a spec compliant discovery

config/config.sample.php

@@ -2276,6 +2276,24 @@
 	 */
 	'sharing.federation.allowSelfSignedCertificates' => false,
 
+	/**
+	 * Override the ``apiVersion`` advertised in the local OCM discovery document.
+	 * Setting this to a non-empty string also removes the non-standard ``version``
+	 * field. Leave empty for compatibility with older Nextcloud servers.
+	 *
+	 * Defaults to ``''`` (empty string)
+	 */
+	'sharing.federation.ocm.apiVersion' => '',
+
+	/**
+	 * Remove the non-standard ``publicKey`` field from the local OCM discovery
+	 * document. Enable this only when all federated peers support RFC 9421 HTTP
+	 * signatures, for example when all peers run Nextcloud 35 or higher.
+	 *
+	 * Defaults to ``false``
+	 */
+	'sharing.federation.ocm.removePublicKey' => false,
+
 	/**
 	 * Hashing
 	 */

lib/private/OCM/Model/OCMProvider.php

@@ -21,6 +21,8 @@
  */
 class OCMProvider implements IOCMProvider {
 	private bool $enabled = false;
+	private bool $removePublicKey = false;
+	private bool $removeVersion = false;
 	private string $apiVersion = '';
 	private string $inviteAcceptDialog = '';
 	private array $capabilities = [];
@@ -350,6 +352,22 @@ private function looksValid(): bool {
 		return ($this->getApiVersion() !== '' && $this->getEndPoint() !== '');
 	}
 
+	/**
+	 * @since 35.0.0
+	 */
+	#[\Override]
+	public function removePublicKey(): void {
+		$this->removePublicKey = true;
+	}
+
+	/**
+	 * @since 35.0.0
+	 */
+	#[\Override]
+	public function removeVersion(): void {
+		$this->removeVersion = true;
+	}
+
 	/**
 	 * @since 28.0.0
 	 */
@@ -370,6 +388,15 @@ public function jsonSerialize(): array {
 			'resourceTypes' => $resourceTypes
 		];
 
+		if ($this->removeVersion) {
+			$response['apiVersion'] = $this->getApiVersion();
+			unset($response['version']);
+		}
+
+		if ($this->removePublicKey) {
+			unset($response['publicKey']);
+		}
+
 		if ($this->capabilities !== []) {
 			$response['capabilities'] = $this->capabilities;
 		}

lib/private/OCM/OCMDiscoveryService.php

@@ -247,6 +247,15 @@ public function getLocalOCMProvider(bool $fullDetails = true): IOCMProvider {
 		$event = new ResourceTypeRegisterEvent($provider);
 		$this->eventDispatcher->dispatchTyped($event);
 
+		$apiVersion = $this->config->getSystemValueString('sharing.federation.ocm.apiVersion');
+		if ($apiVersion !== '') {
+			$provider->setApiVersion($apiVersion);
+			$provider->removeVersion();
+		}
+		if ($this->config->getSystemValueBool('sharing.federation.ocm.removePublicKey')) {
+			$provider->removePublicKey();
+		}
+
 		$this->localProvider = $provider;
 		return $provider;
 	}

lib/public/OCM/Events/LocalOCMDiscoveryEvent.php

@@ -65,4 +65,33 @@ public function registerResourceType(string $name, array $shareTypes, array $pro
 	public function getProvider(): IOCMProvider {
 		return $this->provider;
 	}
+
+	/**
+	 * Remove the non-standard publicKey field from OCM discovery
+	 *
+	 * @since 35.0.0
+	 */
+	public function removePublicKey(): void {
+		$this->provider->removePublicKey();
+	}
+
+	/**
+	 * Remove the non-standard version field from OCM discovery
+	 *
+	 * @since 35.0.0
+	 */
+	public function removeVersion(): void {
+		$this->provider->removeVersion();
+	}
+
+	/**
+	 * Set the apiVersion
+	 *
+	 * @param string $version
+	 *
+	 * @since 35.0.0
+	 */
+	public function setApiVersion(string $version): void {
+		$this->provider->setApiVersion($version);
+	}
 }

lib/public/OCM/IOCMProvider.php

@@ -57,6 +57,20 @@ public function setApiVersion(string $apiVersion): static;
 	 */
 	public function getApiVersion(): string;
 
+	/**
+	 * Remove the non-standard publicKey field from OCM discovery
+	 *
+	 * @since 35.0.0
+	 */
+	public function removePublicKey(): void;
+
+	/**
+	 * Remove the non-standard version field from OCM discovery
+	 *
+	 * @since 35.0.0
+	 */
+	public function removeVersion(): void;
+
 	/**
 	 * configure endpoint
 	 *
@@ -240,7 +254,7 @@ public function import(array $data): static;
 	/**
 	 * @return array{
 	 *     enabled: bool,
-	 *     apiVersion: '1.0-proposal1',
+	 *     apiVersion: string,
 	 *     endPoint: string,
 	 *     publicKey?: array{
 	 *         keyId: string,
@@ -251,7 +265,7 @@ public function import(array $data): static;
 	 *         shareTypes: list<string>,
 	 *         protocols: array<string, string>
 	 *     }>,
-	 *     version: string,
+	 *     version?: string,
 	 *     jwksUri?: string
 	 * }
 	 * @since 28.0.0