feat(files_sharing): fetch remote avatars for external shares

lib/composer/composer/autoload_classmap.php

@@ -1309,6 +1309,7 @@
     'OC\\Avatar\\AvatarManager' => $baseDir . '/lib/private/Avatar/AvatarManager.php',
     'OC\\Avatar\\GuestAvatar' => $baseDir . '/lib/private/Avatar/GuestAvatar.php',
     'OC\\Avatar\\PlaceholderAvatar' => $baseDir . '/lib/private/Avatar/PlaceholderAvatar.php',
+    'OC\\Avatar\\RemoteAvatar' => $baseDir . '/lib/private/Avatar/RemoteAvatar.php',
     'OC\\Avatar\\UserAvatar' => $baseDir . '/lib/private/Avatar/UserAvatar.php',
     'OC\\BackgroundJob\\JobClassesRegistry' => $baseDir . '/lib/private/BackgroundJob/JobClassesRegistry.php',
     'OC\\BackgroundJob\\JobList' => $baseDir . '/lib/private/BackgroundJob/JobList.php',

lib/composer/composer/autoload_static.php

@@ -1350,6 +1350,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OC\\Avatar\\AvatarManager' => __DIR__ . '/../../..' . '/lib/private/Avatar/AvatarManager.php',
         'OC\\Avatar\\GuestAvatar' => __DIR__ . '/../../..' . '/lib/private/Avatar/GuestAvatar.php',
         'OC\\Avatar\\PlaceholderAvatar' => __DIR__ . '/../../..' . '/lib/private/Avatar/PlaceholderAvatar.php',
+        'OC\\Avatar\\RemoteAvatar' => __DIR__ . '/../../..' . '/lib/private/Avatar/RemoteAvatar.php',
         'OC\\Avatar\\UserAvatar' => __DIR__ . '/../../..' . '/lib/private/Avatar/UserAvatar.php',
         'OC\\BackgroundJob\\JobClassesRegistry' => __DIR__ . '/../../..' . '/lib/private/BackgroundJob/JobClassesRegistry.php',
         'OC\\BackgroundJob\\JobList' => __DIR__ . '/../../..' . '/lib/private/BackgroundJob/JobList.php',

lib/private/Avatar/AvatarManager.php

@@ -13,6 +13,7 @@
 use OC\User\Manager;
 use OCP\Accounts\IAccountManager;
 use OCP\Accounts\PropertyDoesNotExistException;
+use OCP\Federation\ICloudIdManager;
 use OCP\Files\IAppData;
 use OCP\Files\NotFoundException;
 use OCP\Files\NotPermittedException;
@@ -53,6 +54,11 @@ public function __construct(
 	 */
 	#[\Override]
 	public function getAvatar(string $userId): IAvatar {
+		$cloudIdManager = \OCP\Server::get(ICloudIdManager::class);
+		if ($cloudIdManager->isValidCloudId($userId)) {
+			return $this->getRemoteAvatar($userId);
+		}
+
 		$user = $this->userManager->get($userId);
 		if ($user === null) {
 			throw new \Exception('user does not exist');
@@ -134,4 +140,25 @@ public function deleteUserAvatar(string $userId): void {
 	public function getGuestAvatar(string $name): IAvatar {
 		return new GuestAvatar($name, $this->config, $this->logger);
 	}
+
+	/**
+	 * Returns a RemoteAvatar
+	 *
+	 * @param string $userId The \OCP\Federation\ICloudId of the remote account, e.g. account@example.com
+	 */
+	private function getRemoteAvatar(string $userId): IAvatar {
+		try {
+			$remoteAvatarFolder = $this->appData->getFolder('__remote');
+		} catch (NotFoundException $e) {
+			$remoteAvatarFolder = $this->appData->newFolder('__remote');
+		}
+
+		try {
+			$folder = $remoteAvatarFolder->getFolder($userId);
+		} catch (NotFoundException $e) {
+			$folder = $remoteAvatarFolder->newFolder($userId);
+		}
+
+		return new RemoteAvatar($folder, $userId, $this->config, $this->logger);
+	}
 }

lib/private/Avatar/RemoteAvatar.php

@@ -0,0 +1,135 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+declare(strict_types=1);
+
+namespace OC\Avatar;
+
+use OCP\Federation\ICloudId;
+use OCP\Federation\ICloudIdManager;
+use OCP\Files\SimpleFS\ISimpleFile;
+use OCP\Files\SimpleFS\ISimpleFolder;
+use OCP\Http\Client\IClientService;
+use OCP\IConfig;
+use Psr\Log\LoggerInterface;
+
+class RemoteAvatar extends Avatar {
+	private const IMAGE_CACHE_AGE = 60 * 60 * 24; // One day
+
+	private ICloudId $cloudId;
+
+	public function __construct(
+		protected ISimpleFolder $folder,
+		protected string $userId,
+		protected IConfig $config,
+		protected LoggerInterface $logger,
+	) {
+		parent::__construct($config, $logger);
+
+		$cloudIdManager = \OCP\Server::get(ICloudIdManager::class);
+		$this->cloudId = $cloudIdManager->resolveCloudId($userId);
+	}
+
+	#[\Override]
+	public function exists(): bool {
+		return true;
+	}
+
+	#[\Override]
+	public function getDisplayName(): string {
+		return $this->cloudId->getDisplayId();
+	}
+
+	/**
+	 * Setting avatars isn't implemented for remote accounts
+	 */
+	#[\Override]
+	public function set($data): void {
+	}
+
+	/**
+	 * Removing avatars isn't implemented for remote accounts
+	 */
+	#[\Override]
+	public function remove(bool $silent = false): void {
+	}
+
+	#[\Override]
+	public function getFile(int $size, bool $darkTheme = false): ISimpleFile {
+		if ($size === -1) {
+			$filename = 'avatar' . ($darkTheme ? '-dark' : '');
+		} else {
+			$filename = 'avatar' . ($darkTheme ? '-dark' : '') . '.' . $size;
+		}
+
+		$avatar = null;
+		$files = $this->folder->getDirectoryListing();
+		foreach ($files as $file) {
+			if (pathinfo($file->getName(), PATHINFO_FILENAME) === $filename) {
+				$avatar = $file;
+				break;
+			}
+		}
+
+		if ($avatar !== null) {
+			// check if a remote avatar is at least a day old, in case a new avatar was uploaded
+			$isAvatarOld = (time() - $avatar->getMTime()) >= self::IMAGE_CACHE_AGE;
+			if (!$isAvatarOld) {
+				return $avatar;
+			}
+		}
+
+		$url = rtrim($this->cloudId->getRemote(), '/') . '/index.php/avatar/' . rawurlencode($this->cloudId->getUser()) . '/' . $size;
+		if ($darkTheme) {
+			$url .= '/dark';
+		}
+
+		$clientService = \OCP\Server::get(IClientService::class);
+		$client = $clientService->newClient();
+		$response = $client->get($url, [
+			'verify' => !$this->config->getSystemValueBool('sharing.federation.allowSelfSignedCertificates', false)
+		]);
+
+		$contentType = $response->getHeader('Content-Type');
+		if (str_starts_with($contentType, 'image/') === false) {
+			throw new \Exception('Unknown filetype');
+		}
+
+		$avatar = $response->getBody();
+		if ($avatar === null) {
+			throw new \Exception('Failed to fetch remote avatar');
+		}
+
+		if (is_resource($avatar)) {
+			$avatar = stream_get_contents($avatar);
+			if ($avatar === false) {
+				throw new \Exception('Failed to fetch remote avatar');
+			}
+		}
+
+		$ext = match ($contentType) {
+			'image/png' => 'png',
+			'image/jpg', 'image/jpeg' => 'jpg',
+			'image/gif' => 'gif',
+			'image/webp' => 'webp',
+			default => 'png',
+		};
+		return $this->folder->newFile($filename . '.' . $ext, $avatar);
+	}
+
+	/**
+	 * Handling user changes isn't implemented for remote accounts
+	 */
+	#[\Override]
+	public function userChanged(string $feature, $oldValue, $newValue): void {
+	}
+
+	#[\Override]
+	public function isCustomAvatar(): bool {
+		return true;
+	}
+}

tests/lib/Avatar/AvatarManagerTest.php

@@ -10,13 +10,16 @@
 
 use OC\Avatar\AvatarManager;
 use OC\Avatar\PlaceholderAvatar;
+use OC\Avatar\RemoteAvatar;
 use OC\Avatar\UserAvatar;
 use OC\KnownUser\KnownUserService;
 use OC\User\Manager;
 use OC\User\User;
 use OCP\Accounts\IAccount;
 use OCP\Accounts\IAccountManager;
 use OCP\Accounts\IAccountProperty;
+use OCP\Federation\ICloudId;
+use OCP\Federation\ICloudIdManager;
 use OCP\Files\IAppData;
 use OCP\Files\SimpleFS\ISimpleFolder;
 use OCP\IConfig;
@@ -73,19 +76,6 @@ protected function setUp(): void {
 		);
 	}
 
-	public function testGetAvatarInvalidUser(): void {
-		$this->expectException(\Exception::class);
-		$this->expectExceptionMessage('user does not exist');
-
-		$this->userManager
-			->expects($this->once())
-			->method('get')
-			->with('invalidUser')
-			->willReturn(null);
-
-		$this->avatarManager->getAvatar('invalidUser');
-	}
-
 	public function testGetAvatarForSelf(): void {
 		$user = $this->createMock(User::class);
 		$user
@@ -276,4 +266,70 @@ public function testGetAvatarScopes($avatarScope, $isPublicCall, $isKnownUser, $
 		}
 		$this->assertEquals($expected, $this->avatarManager->getAvatar('valid-user'));
 	}
+
+	public function testGetAvatarInvalidUser(): void {
+		$this->expectException(\Exception::class);
+		$this->expectExceptionMessage('user does not exist');
+
+		$this->userManager
+			->expects($this->once())
+			->method('get')
+			->with('invalidUser')
+			->willReturn(null);
+
+		$this->avatarManager->getAvatar('invalidUser');
+	}
+
+	public function testGetAvatarForRemoteUser(): void {
+		$cloudId = 'user@https://remote.example.com';
+
+		$this->userManager
+			->expects($this->never())
+			->method('get');
+
+		$resolvedCloudId = $this->createMock(ICloudId::class);
+		$resolvedCloudId->method('getUser')->willReturn('user');
+		$resolvedCloudId->method('getRemote')->willReturn('https://remote.example.com');
+		$resolvedCloudId->method('getDisplayId')->willReturn('user@remote.example.com');
+
+		$cloudIdManager = $this->createMock(ICloudIdManager::class);
+		$cloudIdManager->expects($this->once())
+			->method('isValidCloudId')
+			->with($cloudId)
+			->willReturn(true);
+		$cloudIdManager->method('resolveCloudId')
+			->with($cloudId)
+			->willReturn($resolvedCloudId);
+		$this->overwriteService(ICloudIdManager::class, $cloudIdManager);
+
+		$this->appData->expects($this->once())->method('getFolder');
+		$this->accountManager->expects($this->never())->method('getAccount');
+
+		$avatar = $this->avatarManager->getAvatar($cloudId);
+
+		self::assertInstanceOf(RemoteAvatar::class, $avatar);
+		self::assertTrue($avatar->exists());
+		self::assertTrue($avatar->isCustomAvatar());
+		self::assertSame('user@remote.example.com', $avatar->getDisplayName());
+	}
+
+	public function testGetAvatarThrowsForUnknownUserThatIsNotACloudId(): void {
+		$this->expectException(\Exception::class);
+		$this->expectExceptionMessage('user does not exist');
+
+		$this->userManager
+			->expects($this->once())
+			->method('get')
+			->with('invalidUser')
+			->willReturn(null);
+
+		$cloudIdManager = $this->createMock(ICloudIdManager::class);
+		$cloudIdManager->expects($this->once())
+			->method('isValidCloudId')
+			->with('invalidUser')
+			->willReturn(false);
+		$this->overwriteService(ICloudIdManager::class, $cloudIdManager);
+
+		$this->avatarManager->getAvatar('invalidUser');
+	}
 }