Enhance avatar upload handling by providing immediate preview data and improving cache write logic

b0esche_cloud/lib/widgets/account_settings_dialog.dart

@@ -113,6 +113,19 @@ class _AccountSettingsDialogState extends State<AccountSettingsDialog> {
             _avatarUploadProgress = 0.0;
           });
 
+          // Immediately show a preview if the server returned the avatar bytes
+          try {
+            final avatarData = response['avatarData'] as String?;
+            final contentType = response['contentType'] as String?;
+            if (avatarData != null && contentType != null) {
+              setState(() {
+                _avatarUrl = 'data:$contentType;base64,$avatarData';
+              });
+            }
+          } catch (_) {
+            // ignore
+          }
+
           // Fetch latest profile from backend so we get the canonical avatar URL and version
           try {
             final apiClient = GetIt.I<ApiClient>();

go_cloud/internal/http/routes.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"context"
 	"database/sql"
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -84,7 +85,11 @@ func writeAvatarCache(cfg *config.Config, userID string, version string, ext str
 		dir = fallback
 	}
 	p := avatarCachePath(&config.Config{AvatarCacheDir: dir}, userID, version, ext)
-	return os.WriteFile(p, data, 0644)
+	if err := os.WriteFile(p, data, 0644); err != nil {
+		return err
+	}
+	fmt.Printf("[INFO] Wrote avatar cache for user=%s v=%s path=%s size=%d\n", userID, version, p, len(data))
+	return nil
 }
 
 // readAvatarCache attempts to read a cached avatar for a user and optional version. If version is provided, it looks for an exact match; otherwise it returns the latest available cached avatar (if any).
@@ -96,9 +101,12 @@ func readAvatarCache(cfg *config.Config, userID string, version string) ([]byte,
 	// Also check fallback tmp dir
 	checkDirs = append(checkDirs, filepath.Join(os.TempDir(), "b0esche_avatars"))
 
+	fmt.Printf("[DEBUG] readAvatarCache checking dirs=%v for user=%s version=%s\n", checkDirs, userID, version)
+
 	for _, dir := range checkDirs {
 		entries, err := os.ReadDir(dir)
 		if err != nil {
+			fmt.Printf("[DEBUG] readAvatarCache cannot read dir %s: %v\n", dir, err)
 			continue
 		}
 		if version != "" {
@@ -107,8 +115,10 @@ func readAvatarCache(cfg *config.Config, userID string, version string) ([]byte,
 			for _, e := range entries {
 				if strings.HasPrefix(e.Name(), prefix) {
 					p := filepath.Join(dir, e.Name())
+					fmt.Printf("[INFO] Found cached avatar for user=%s v=%s path=%s\n", userID, version, p)
 					b, err := os.ReadFile(p)
 					if err != nil {
+						fmt.Printf("[WARN] failed to read cached avatar %s: %v\n", p, err)
 						return nil, "", err
 					}
 					ext := filepath.Ext(e.Name())
@@ -120,6 +130,7 @@ func readAvatarCache(cfg *config.Config, userID string, version string) ([]byte,
 				}
 			}
 			// not found
+			fmt.Printf("[DEBUG] no exact cached avatar match in %s for prefix=%s\n", dir, prefix)
 			continue
 		}
 		// no version specified: return latest by modtime of files starting with userID.
@@ -139,8 +150,10 @@ func readAvatarCache(cfg *config.Config, userID string, version string) ([]byte,
 		}
 		if latest != nil {
 			p := filepath.Join(dir, latestName)
+			fmt.Printf("[INFO] Found latest cached avatar for user=%s path=%s\n", userID, p)
 			b, err := os.ReadFile(p)
 			if err != nil {
+				fmt.Printf("[WARN] failed to read cached avatar %s: %v\n", p, err)
 				return nil, "", err
 			}
 			ext := filepath.Ext(latestName)
@@ -4213,8 +4226,11 @@ func uploadUserAvatarHandler(w http.ResponseWriter, r *http.Request, db *databas
 	}
 	// Save avatar bytes to local cache keyed by version so it survives restarts and avoids unnecessary re-downloads
 	versionStr := fmt.Sprintf("%d", version)
+	cached := false
 	if err := writeAvatarCache(cfg, userID.String(), versionStr, ext, fileBytes); err != nil {
 		fmt.Printf("[WARN] failed to write avatar cache for user=%s version=%s: %v\n", userID.String(), versionStr, err)
+	} else {
+		cached = true
 	}
 
 	// Audit log
@@ -4228,14 +4244,20 @@ func uploadUserAvatarHandler(w http.ResponseWriter, r *http.Request, db *databas
 		},
 	})
 
+	// Provide avatarData for immediate preview (small images only)
+	avatarData := base64.StdEncoding.EncodeToString(fileBytes)
+
 	publicURL := fmt.Sprintf("https://go.b0esche.cloud/user/avatar?v=%d", version)
 	if token, ok := middleware.GetToken(r.Context()); ok && token != "" {
 		publicURL = fmt.Sprintf("%s&token=%s", publicURL, token)
 	}
 	w.Header().Set("Content-Type", "application/json")
 	json.NewEncoder(w).Encode(map[string]interface{}{
-		"message":   "Avatar uploaded successfully",
-		"avatarUrl": publicURL,
+		"message":     "Avatar uploaded successfully",
+		"avatarUrl":   publicURL,
+		"cached":      cached,
+		"avatarData":  avatarData,
+		"contentType": contentType,
 	})
 }