fix: improve error handling in directory monitoring and add nil check…

… for Redis client in thumbnail verification

cmd/server/main.go

@@ -2839,19 +2839,19 @@ func monitorDirectoryChanges(dir string) {
 	for {
 		select {
 		case event, ok := <-watcher.Events:
-			if !ok {
+			if (!ok) {
 				return
 			}
-			if event.Op&fsnotify.Create == fsnotify.Create || event.Op&fsnotify.Remove == fsnotify.Remove {
+			if (event.Op&fsnotify.Create == fsnotify.Create || event.Op&fsnotify.Remove == fsnotify.Remove) {
 				log.Infof("Directory change detected: %s", event.String())
 				// Update caches and indices
 				err := precacheStoragePath(dir)
-				if err != nil {
+				if (err != nil) {
 					log.Error("Failed to update precache after directory change:", err)
 				}
 			}
 		case err, ok := <-watcher.Errors:
-			if !ok {
+			if (!ok) {
 				return
 			}
 			log.Error("Directory watcher error:", err)
@@ -3132,6 +3132,12 @@ func handleThumbnails(w http.ResponseWriter, r *http.Request) {
 
 // verifyAndRepairThumbnails verifies the integrity of thumbnail files and repairs them if necessary
 func verifyAndRepairThumbnails(thumbnailPaths []string, redisClient *redis.Client, originalDir string) {
+	// Check if redisClient is nil
+	if redisClient == nil {
+		log.Warn("Redis client is nil. Skipping thumbnail verification and repair.")
+		return
+	}
+
 	// Check if thumbnailPaths is nil or empty
 	if len(thumbnailPaths) == 0 {
 		log.Error("Thumbnail paths are nil or empty. Nothing to verify or repair.")