Improve avatar cache handling by adding fallback directory creation and enhancing read logic

go_cloud/internal/http/routes.go

@@ -65,32 +65,50 @@ func avatarCachePath(cfg *config.Config, userID string, ext string) string {
 }
 
 func writeAvatarCache(cfg *config.Config, userID string, ext string, data []byte) error {
-	p := avatarCachePath(cfg, userID, ext)
-	return os.WriteFile(p, data, 0644)
-}
-
-func readAvatarCache(cfg *config.Config, userID string) ([]byte, string, error) {
 	dir := cfg.AvatarCacheDir
 	if dir == "" {
 		dir = "/var/cache/b0esche/avatars"
 	}
-	entries, err := os.ReadDir(dir)
-	if err != nil {
-		return nil, "", err
+	// Try to create the directory; if it fails, fall back to temp dir
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		fmt.Printf("[WARN] failed to create avatar cache dir %s: %v; trying fallback to tmp dir\n", dir, err)
+		fallback := filepath.Join(os.TempDir(), "b0esche_avatars")
+		if err2 := os.MkdirAll(fallback, 0755); err2 != nil {
+			return fmt.Errorf("failed to create avatar cache dir: %v; fallback failed: %v", err, err2)
+		}
+		dir = fallback
 	}
-	for _, e := range entries {
-		if strings.HasPrefix(e.Name(), userID+".") {
-			p := filepath.Join(dir, e.Name())
-			b, err := os.ReadFile(p)
-			if err != nil {
-				return nil, "", err
+	p := filepath.Join(dir, fmt.Sprintf("%s%s", userID, ext))
+	return os.WriteFile(p, data, 0644)
+}
+
+func readAvatarCache(cfg *config.Config, userID string) ([]byte, string, error) {
+	checkDirs := []string{cfg.AvatarCacheDir}
+	if checkDirs[0] == "" {
+		checkDirs[0] = "/var/cache/b0esche/avatars"
+	}
+	// Also check fallback tmp dir
+	checkDirs = append(checkDirs, filepath.Join(os.TempDir(), "b0esche_avatars"))
+
+	for _, dir := range checkDirs {
+		entries, err := os.ReadDir(dir)
+		if err != nil {
+			continue
+		}
+		for _, e := range entries {
+			if strings.HasPrefix(e.Name(), userID+".") {
+				p := filepath.Join(dir, e.Name())
+				b, err := os.ReadFile(p)
+				if err != nil {
+					return nil, "", err
+				}
+				ext := filepath.Ext(e.Name())
+				ct := mime.TypeByExtension(ext)
+				if ct == "" {
+					ct = "application/octet-stream"
+				}
+				return b, ct, nil
 			}
-			ext := filepath.Ext(e.Name())
-			ct := mime.TypeByExtension(ext)
-			if ct == "" {
-				ct = "application/octet-stream"
-			}
-			return b, ct, nil
 		}
 	}
 	return nil, "", fmt.Errorf("cache miss")