feat: custom stickers apis

internal/service/social_service.go

@@ -775,6 +775,29 @@ func (s *CollectionService) CoverPresign(ctx context.Context, userID, contentTyp
 // presignImage builds an R2 presign for a user-scoped media key under the
 // given prefix. The random suffix invalidates browser caches when the image
 // is replaced.
+// presignImageKey is presignImage's sibling for callers that store the storage
+// KEY rather than a URL — so the CDN domain can change without rewriting rows.
+// Handing those callers a public URL silently doubles it at read time.
+func presignImageKey(ctx context.Context, r2 *repository.R2, prefix, name, contentType string) (uploadURL, key string, err error) {
+	if r2 == nil {
+		return "", "", errors.New("media uploads are not configured")
+	}
+	ext, ok := imageExtensionFor(contentType)
+	if !ok {
+		return "", "", fmt.Errorf("unsupported content type: %s", contentType)
+	}
+	suffix := make([]byte, 8)
+	if _, err := rand.Read(suffix); err != nil {
+		return "", "", err
+	}
+	key = path.Join(prefix, name, hex.EncodeToString(suffix)+ext)
+	uploadURL, _, err = r2.PresignPut(ctx, key, contentType, 5*time.Minute)
+	if err != nil {
+		return "", "", err
+	}
+	return uploadURL, key, nil
+}
+
 func presignImage(ctx context.Context, r2 *repository.R2, prefix, userID, contentType string) (uploadURL, publicURL string, err error) {
 	if r2 == nil {
 		return "", "", errors.New("media uploads are not configured")