perf: Batch getting the display names of groups

Signed-off-by: Carl Schwan <carlschwan@kde.org>

Author: CarlSchwan

apps/provisioning_api/lib/Controller/AUserDataOCSController.php

@@ -274,10 +274,11 @@ protected function findGroupsWithDisplayname(array $userDetails): array {
 		$groupIds = array_unique($groupIds);
 		sort($groupIds);
 
-		return array_map(function ($groupId) {
-			$displayname = $this->groupDisplayNameCache->getDisplayName($groupId) ?? $groupId;
-			return ['id' => $groupId, 'displayname' => $displayname];
-		}, $groupIds);
+		$info = [];
+		foreach ($this->groupDisplayNameCache->getDisplayNames($groupIds) as $groupId => $displayName) {
+			$info[] = ['id' => $groupId, 'displayname' => $displayName ?? $groupId];
+		}
+		return $info;
 	}
 
 	/**

apps/provisioning_api/tests/Controller/GroupsControllerTest.php

@@ -495,9 +495,9 @@ public function testGetGroupUsersDetails(): void {
 			->willReturn([]);
 
 		$this->groupDisplayNameCache
-			->method('getDisplayName')
-			->with('ncg1')
-			->willReturn('Group One');
+			->method('getDisplayNames')
+			->with(['ncg1'])
+			->willReturn(['ncg1' => 'Group One']);
 
 		$result = $this->api->getGroupUsersDetails($gid);
 
@@ -550,9 +550,9 @@ public function testGetGroupUsersDetailsEncoded(): void {
 			->willReturn([]);
 
 		$this->groupDisplayNameCache
-			->method('getDisplayName')
-			->with('Department A/B C/D')
-			->willReturn('Department A/B C/D-name');
+			->method('getDisplayNames')
+			->with(['Department A/B C/D'])
+			->willReturn(['Department A/B C/D' => 'Department A/B C/D-name']);
 
 		$result = $this->api->getGroupUsersDetails(urlencode($gid));
 

lib/private/Group/DisplayNameCache.php

@@ -55,6 +55,45 @@ public function getDisplayName(string $groupId): ?string {
 		return $displayName;
 	}
 
+	/**
+	 * @param list<string> $groupIds
+	 * @return array<string, ?string>
+	 */
+	public function getDisplayNames(array $groupIds): array {
+		$result = [];
+		$missing = [];
+		foreach ($groupIds as $groupId) {
+			if (isset($this->cache[$groupId])) {
+				$result[$groupId] = $this->cache[$groupId];
+			} else {
+				$displayName = $this->memCache->get($groupId);
+				if ($displayName) {
+					$this->cache[$groupId] = $displayName;
+					$result[$groupId] = $displayName;
+				} else {
+					$missing[] = $groupId;
+				}
+			}
+		}
+
+		/** @var Manager $groupManager */
+		$groupManager = $this->groupManager;
+		$groups = $groupManager->getGroupsObjects($missing);
+		$stillMissingGroups = array_diff($missing, array_keys($groups));
+		foreach ($groups as $groupId => $group) {
+			$displayName = $group->getDisplayName() ?? $group->getGID();
+			$this->cache[$groupId] = $displayName;
+			$this->memCache->set($groupId, $displayName, 60 * 10); // 10 minutes
+			$result[$groupId] = $displayName;
+		}
+
+		foreach ($stillMissingGroups as $groupId) {
+			$result[$groupId] = null;
+		}
+
+		return $result;
+	}
+
 	public function clear(): void {
 		$this->cache = new CappedMemoryCache();
 		$this->memCache->clear();

lib/private/Group/Manager.php

@@ -170,7 +170,7 @@ protected function getGroupObject($gid, $displayName = null) {
 	 * @param array<string, string> $displayNames Array containing already know display name for a groupId
 	 * @return array<string, IGroup>
 	 */
-	protected function getGroupsObjects(array $gids, array $displayNames = []): array {
+	public function getGroupsObjects(array $gids, array $displayNames = []): array {
 		$backends = [];
 		$groups = [];
 		foreach ($gids as $gid) {