feat: add optional avatar cache

README.md

@@ -76,6 +76,40 @@ Key                   | Description
 `api.url`             | URL to your BBB server. Should start with `https://`
 `api.secret`          | Secret of your BBB server
 `app.shortener`       | Value of your shortener service. Should start with `https://` and contain `{token}`.
+`avatar.path`         | Absolute path to an optional avatar cache directory.
+`avatar.url`          | URL which serves `avatar.path` to be used as avatar cache.
+
+### Avatar cache (v2.2+)
+The generation of avatars puts a high load on your Nextcloud instance, since the
+number of requests increases squarely to the number of participants in a room.
+To mitigate this situation, this app provides an optional avatar file cache. To
+activate the cache `avatar.path` and `avatar.url` have to be configured.
+`avatar.path` must provide an absolute path (e.g. `/srv/bbb-avatar-cache/`) to a
+directory which is writable by the PHP user. `avatar.url` must contain the url
+which serves all files from `avatar.path`. To bypass browser connection limits
+we recommend to setup a dedicated host.
+
+Example Apache configuration for a dedicated host with `avatar.path = /srv/bbb-avatar-cache/`
+and `avatar.url = https://avatar-cache.your-nextcloud.com/`:
+
+```
+<VirtualHost *:443>
+        ServerName avatar-cache.your-nextcloud.com
+
+        Header always set Strict-Transport-Security "max-age=15768000;"
+
+        DocumentRoot /srv/bbb-avatar-cache
+        <Directory /srv/bbb-avatar-cache>
+                Options -FollowSymLinks -Indexes
+        </Directory>
+
+        SSLEngine On
+        # SSL config...
+</VirtualHost>
+```
+
+For additional security, we recommend to disable directory listing, symlinks and
+any language interpreter such as php for the cache directory.
 
 
 ## :bowtie: User guide

lib/AvatarRepository.php

@@ -0,0 +1,166 @@
+<?php
+
+namespace OCA\BigBlueButton;
+
+use OCA\BigBlueButton\AppInfo\Application;
+use OCA\BigBlueButton\Db\Room;
+use OCP\IAvatarManager;
+use OCP\IConfig;
+use OCP\IURLGenerator;
+use OCP\Security\ISecureRandom;
+
+class AvatarRepository {
+	public const CONF_KEY_PATH = 'avatar.path';
+	public const CONF_KEY_URL = 'avatar.url';
+
+	/** @var IAvatarManager */
+	private $avatarManager;
+
+	/** @var ISecureRandom */
+	private $random;
+
+	/** @var IURLGenerator */
+	private $urlGenerator;
+
+	/** @var IConfig */
+	private $config;
+
+	public function __construct(
+		IAvatarManager $avatarManager,
+		IURLGenerator $urlGenerator,
+		ISecureRandom $random,
+		IConfig $config) {
+		$this->avatarManager = $avatarManager;
+		$this->urlGenerator = $urlGenerator;
+		$this->random = $random;
+		$this->config = $config;
+	}
+
+	public function getAvatarUrl(Room $room, string $userId): string {
+		if (!$this->isAvatarCacheConfigured()) {
+			return $this->urlGenerator->linkToRouteAbsolute('core.avatar.getAvatar', ['userId' => $userId, 'size' => 32]);
+		}
+
+		$roomDirName = $room->uid . '-' . $this->generateUrlSafeRandom(16);
+		$roomDirPath = $this->getRootPath() . $roomDirName . DIRECTORY_SEPARATOR;
+
+		if (!file_exists($roomDirPath)) {
+			if (!mkdir($roomDirPath, 0755, true)) {
+				throw new \RuntimeException('Can not create room directory: ' . $roomDirPath);
+			}
+
+			file_put_contents($roomDirPath . 'index.html', '');
+
+			if (!file_exists($this->getRootPath() . 'index.html')) {
+				file_put_contents($this->getRootPath() . 'index.html', 'Avatar cache is working.');
+			}
+		}
+
+		$avatar = $this->avatarManager->getAvatar($userId);
+		$file = $avatar->getFile(32);
+
+		$avatarFileName = $this->generateUrlSafeRandom(16) . '-' . $file->getName();
+		$avatarPath = $roomDirPath . $avatarFileName;
+
+		if (!file_put_contents($avatarPath, $file->getContent())) {
+			throw new \RuntimeException('Could not write avatar file: ' . $avatarPath);
+		}
+
+		chmod($avatarPath, 0644);
+
+		return $this->getBaseUrl() . $roomDirName . '/' . $avatarFileName;
+	}
+
+	public function clearRoom(string $roomUid): int {
+		if (!$this->isAvatarCacheConfigured() || empty($roomUid)) {
+			return 0;
+		}
+
+		$fileCounter = 0;
+
+		foreach (glob($this->getRootPath() . $roomUid . '-*' . DIRECTORY_SEPARATOR) as $dir) {
+			foreach (scandir($dir) as $file) {
+				if (in_array($file, ['.', '..'])) {
+					continue;
+				}
+
+				unlink($dir . $file);
+
+				if ($file !== 'index.html') {
+					$fileCounter++;
+				}
+			}
+
+			rmdir($dir);
+		}
+
+		return $fileCounter;
+	}
+
+	public function clearAllRooms(): array {
+		if (!$this->isAvatarCacheConfigured()) {
+			return [
+				'rooms' => 0,
+				'files' => 0,
+			];
+		}
+
+		$path = $this->getRootPath();
+		$roomCounter = 0;
+		$fileCounter = 0;
+
+		foreach (scandir($path) as $dir) {
+			if (in_array($dir, ['.', '..']) || $dir === 'index.html') {
+				continue;
+			}
+
+			$roomUid = \explode("-", $dir)[0];
+
+			$fileCounter += $this->clearRoom($roomUid);
+
+			$roomCounter++;
+		}
+
+		return [
+			'rooms' => $roomCounter,
+			'files' => $fileCounter,
+		];
+	}
+
+	private function generateUrlSafeRandom(int $length): string {
+		// from Nextcloud 23 ISecureRandom::CHAR_ALPHANUMERIC can be used as shortcut
+		return $this->random->generate($length, ISecureRandom::CHAR_UPPER . ISecureRandom::CHAR_LOWER . ISecureRandom::CHAR_DIGITS);
+	}
+
+	private function isAvatarCacheConfigured(): bool {
+		return !empty($this->getRootPath()) && !empty($this->getBaseUrl());
+	}
+
+	private function getRootPath(): string {
+		$path = $this->config->getAppValue(Application::ID, self::CONF_KEY_PATH);
+
+		if (empty($path)) {
+			return '';
+		}
+
+		return substr($path, -\strlen($path)) === DIRECTORY_SEPARATOR ? $path : ($path . DIRECTORY_SEPARATOR);
+	}
+
+	private function getBaseUrl(): string {
+		$url = $this->config->getAppValue(Application::ID, self::CONF_KEY_URL);
+
+		if (empty($url)) {
+			return '';
+		}
+
+		if (preg_match('/^https?:\/\//', $url) === 0) {
+			$url = $this->urlGenerator->getAbsoluteURL($url);
+		}
+
+		if (preg_match('/\/$/', $url) === 0) {
+			$url .= '/';
+		}
+
+		return $url;
+	}
+}

lib/BigBlueButton/API.php

@@ -10,6 +10,7 @@ use BigBlueButton\Parameters\GetRecordingsParameters;
 use BigBlueButton\Parameters\IsMeetingRunningParameters;
 use BigBlueButton\Parameters\JoinMeetingParameters;
 use OCA\BigBlueButton\AppInfo\Application;
+use OCA\BigBlueButton\AvatarRepository;
 use OCA\BigBlueButton\Crypto;
 use OCA\BigBlueButton\Db\Room;
 use OCA\BigBlueButton\Event\MeetingStartedEvent;
@@ -50,6 +51,9 @@ class API {
 	/** @var IAppManager */
 	private $appManager;
 
+	/** @var AvatarRepository */
+	private $avatarRepository;
+
 	/** @var IRequest */
 	private $request;
 
@@ -62,6 +66,7 @@ class API {
 		UrlHelper $urlHelper,
 		Defaults $defaults,
 		IAppManager $appManager,
+		AvatarRepository $avatarRepository,
 		IRequest $request
 	) {
 		$this->config = $config;
@@ -72,6 +77,7 @@ class API {
 		$this->urlHelper = $urlHelper;
 		$this->defaults = $defaults;
 		$this->appManager = $appManager;
+		$this->avatarRepository = $avatarRepository;
 		$this->request = $request;
 	}
 
@@ -121,8 +127,10 @@ class API {
 		}
 
 		if ($uid) {
-			$joinMeetingParams->setUserId($uid);
+			$avatarUrl = $this->avatarRepository->getAvatarUrl($room, $uid);
-			$joinMeetingParams->setAvatarURL($this->urlGenerator->linkToRouteAbsolute('core.avatar.getAvatar', ['userId' => $uid, 'size' => 32]));
+
+			$joinMeetingParams->setUserID($uid);
+			$joinMeetingParams->setAvatarURL($avatarUrl);
 		}
 
 		return $this->getServer()->getJoinMeetingURL($joinMeetingParams);

lib/Controller/HookController.php

@@ -2,6 +2,7 @@
 
 namespace OCA\BigBlueButton\Controller;
 
+use OCA\BigBlueButton\AvatarRepository;
 use OCA\BigBlueButton\Db\Room;
 use OCA\BigBlueButton\Event\MeetingEndedEvent;
 use OCA\BigBlueButton\Event\RecordingReadyEvent;
@@ -20,6 +21,9 @@ class HookController extends Controller {
 	/** @var RoomService */
 	private $service;
 
+	/** @var AvatarRepository */
+	private $avatarRepository;
+
 	/** @var IEventDispatcher */
 	private $eventDispatcher;
 
@@ -27,11 +31,13 @@ class HookController extends Controller {
 		string $appName,
 		IRequest $request,
 		RoomService $service,
+		AvatarRepository $avatarRepository,
 		IEventDispatcher $eventDispatcher
 	) {
 		parent::__construct($appName, $request);
 
 		$this->service = $service;
+		$this->avatarRepository = $avatarRepository;
 		$this->eventDispatcher = $eventDispatcher;
 	}
 
@@ -55,8 +61,11 @@ class HookController extends Controller {
 	 */
 	public function meetingEnded($recordingmarks = false): void {
 		$recordingmarks = \boolval($recordingmarks);
+		$room = $this->getRoom();
 
-		$this->eventDispatcher->dispatch(MeetingEndedEvent::class, new MeetingEndedEvent($this->getRoom(), $recordingmarks));
+		$this->avatarRepository->clearRoom($room->uid);
+
+		$this->eventDispatcher->dispatch(MeetingEndedEvent::class, new MeetingEndedEvent($room, $recordingmarks));
 	}
 
 	/**