feat: Allow to check user existence outside specific user backends

Signed-off-by: Carl Schwan <carl@carlschwan.eu>

Author: CarlSchwan

lib/private/User/Manager.php

@@ -119,25 +119,29 @@ public function clearBackends(): void {
 	}
 
 	/**
-	 * get a user by user id
-	 *
-	 * @param string $uid
-	 * @return User|null Either the user or null if the specified user does not exist
+	 * {@inheritDoc}
+	 * @param list<string> $excludeBackends A list of IUserBackend::getBackendName() that need to be excluded from the search.
 	 */
 	#[\Override]
-	public function get($uid) {
-		if (is_null($uid) || $uid === '' || $uid === false) {
+	public function get(string $uid, array $excludeBackends = []): \OCP\IUser|null {
+		if ($uid === '') {
 			return null;
 		}
-		if (isset($this->cachedUsers[$uid])) { //check the cache first to prevent having to loop over the backends
-			return $this->cachedUsers[$uid];
-		}
 
 		if (strlen($uid) > IUser::MAX_USERID_LENGTH) {
 			return null;
 		}
 
+		// check the cache first to prevent having to loop over the backends
+		if ($excludeBackends === [] && isset($this->cachedUsers[$uid])) {
+			return $this->cachedUsers[$uid];
+		}
+
 		$cachedBackend = $this->cache->get(sha1($uid));
+		if (in_array($cachedBackend, $excludeBackends)) {
+			$cachedBackend = null;
+		}
+
 		if ($cachedBackend !== null && isset($this->backends[$cachedBackend])) {
 			// Cache has the info of the user backend already, so ask that one directly
 			$backend = $this->backends[$cachedBackend];
@@ -152,6 +156,10 @@ public function get($uid) {
 				continue;
 			}
 
+			if (in_array($i, $excludeBackends)) {
+				continue;
+			}
+
 			if ($backend->userExists($uid)) {
 				// Hash $uid to ensure that only valid characters are used for the cache key
 				$this->cache->set(sha1($uid), $i, 300);
@@ -194,19 +202,13 @@ public function getUserObject($uid, $backend, $cacheUser = true) {
 		return $user;
 	}
 
-	/**
-	 * check if a user exists
-	 *
-	 * @param string $uid
-	 * @return bool
-	 */
 	#[\Override]
-	public function userExists($uid) {
+	public function userExists(string $uid, array $excludeBackends = []): bool {
 		if (strlen($uid) > IUser::MAX_USERID_LENGTH) {
 			return false;
 		}
 
-		$user = $this->get($uid);
+		$user = $this->get($uid, $excludeBackends);
 		return ($user !== null);
 	}
 

lib/public/IUserManager.php

@@ -70,7 +70,7 @@ public function clearBackends();
 	 * @return \OCP\IUser|null Either the user or null if the specified user does not exist
 	 * @since 8.0.0
 	 */
-	public function get($uid);
+	public function get(string $uid): \OCP\IUser|null;
 
 	/**
 	 * Get the display name of a user
@@ -82,13 +82,14 @@ public function get($uid);
 	public function getDisplayName(string $uid): ?string;
 
 	/**
-	 * check if a user exists
+	 * Check if a user exists.
 	 *
 	 * @param string $uid
+	 * @param list<string> $excludeBackends A list of IUserBackend::getBackendName() that need to be excluded from the search.
 	 * @return bool
 	 * @since 8.0.0
 	 */
-	public function userExists($uid);
+	public function userExists(string $uid, array $excludeBackends = []): bool;
 
 	/**
 	 * Check if the password is valid for the user