add MinIO media URL refresh endpoint

Add POST /api/v1/files/refresh-url to issue fresh presigned URLs from object keys, minio:// references, or stale presigned URLs so clients can refresh media links before render.

Made-with: Cursor

internal/pkgs/minio/client.go

@@ -14,6 +14,10 @@ type Client struct {
 	bucketName string
 }
 
+func (c *Client) BucketName() string {
+	return c.bucketName
+}
+
 func NewClient(endpoint, accessKey, secretKey string, useSSL bool, bucketName string) (*Client, error) {
 	mc, err := minio.New(endpoint, &minio.Options{
 		Creds:  credentials.NewStaticV4(accessKey, secretKey, ""),

internal/services/minio/service.go

@@ -66,6 +66,10 @@ func (s *Service) GetURL(ctx context.Context, objectKey string, expiry time.Dura
 	return s.client.GetFileURL(ctx, objectKey, expiry)
 }
 
+func (s *Service) BucketName() string {
+	return s.client.BucketName()
+}
+
 // Delete removes a file from MinIO.
 func (s *Service) Delete(ctx context.Context, objectKey string) error {
 	s.logger.Info("Deleting file from MinIO", zap.String("object_key", objectKey))

internal/web_server/handlers/file_handler.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"strconv"
 	"strings"
 	"time"
@@ -31,6 +32,10 @@ type uploadMediaByURLReq struct {
 	Description string `json:"description"`
 }
 
+type refreshFileURLReq struct {
+	Reference string `json:"reference"`
+}
+
 // resolveFileURL converts a stored file path to a usable URL.
 // If the path starts with "minio://", it generates a presigned URL.
 // Otherwise it returns the path as-is (e.g. "/static/...").
@@ -82,6 +87,93 @@ func (h *Handler) GetFileURL(c *fiber.Ctx) error {
 	})
 }
 
+func (h *Handler) extractObjectKeyFromReference(reference string) (string, error) {
+	ref := strings.TrimSpace(reference)
+	if ref == "" {
+		return "", fmt.Errorf("reference is required")
+	}
+
+	if strings.HasPrefix(ref, "minio://") {
+		key := strings.TrimPrefix(ref, "minio://")
+		if key == "" {
+			return "", fmt.Errorf("invalid minio reference")
+		}
+		return key, nil
+	}
+
+	u, err := url.Parse(ref)
+	if err == nil && u.Scheme != "" && u.Host != "" {
+		path := strings.TrimPrefix(u.Path, "/")
+		if path == "" {
+			return "", fmt.Errorf("invalid file URL")
+		}
+		bucket := strings.TrimSpace(h.minioSvc.BucketName())
+		if bucket != "" {
+			prefix := bucket + "/"
+			if strings.HasPrefix(path, prefix) {
+				path = strings.TrimPrefix(path, prefix)
+			}
+		}
+		if path == "" {
+			return "", fmt.Errorf("invalid file URL")
+		}
+		return path, nil
+	}
+
+	return ref, nil
+}
+
+// RefreshFileURL generates a new presigned URL from an object key, minio:// URI, or stale presigned URL.
+// @Summary Refresh presigned URL for a file
+// @Tags files
+// @Accept json
+// @Produce json
+// @Param body body refreshFileURLReq true "reference (object key, minio://..., or existing presigned URL)"
+// @Success 200 {object} domain.Response
+// @Router /api/v1/files/refresh-url [post]
+func (h *Handler) RefreshFileURL(c *fiber.Ctx) error {
+	if h.minioSvc == nil {
+		return c.Status(fiber.StatusServiceUnavailable).JSON(domain.ErrorResponse{
+			Message: "File storage service is not available",
+		})
+	}
+
+	var req refreshFileURLReq
+	if err := c.BodyParser(&req); err != nil {
+		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
+			Message: "Invalid request body",
+			Error:   err.Error(),
+		})
+	}
+
+	objectKey, err := h.extractObjectKeyFromReference(req.Reference)
+	if err != nil {
+		return c.Status(fiber.StatusBadRequest).JSON(domain.ErrorResponse{
+			Message: "Invalid file reference",
+			Error:   err.Error(),
+		})
+	}
+
+	freshURL, err := h.minioSvc.GetURL(c.Context(), objectKey, 1*time.Hour)
+	if err != nil {
+		return c.Status(fiber.StatusInternalServerError).JSON(domain.ErrorResponse{
+			Message: "Failed to refresh file URL",
+			Error:   err.Error(),
+		})
+	}
+
+	return c.Status(fiber.StatusOK).JSON(domain.Response{
+		Message: "File URL refreshed",
+		Data: map[string]interface{}{
+			"object_key": objectKey,
+			"url":        freshURL,
+			"expires_in": int((1 * time.Hour).Seconds()),
+		},
+		Success:    true,
+		StatusCode: fiber.StatusOK,
+	})
+}
+
 // UploadMedia uploads an image/audio/video file and returns its URL and key.
 // @Summary Upload media file
 // @Tags files

internal/web_server/routes.go

@@ -113,6 +113,7 @@ func (a *App) initAppRoutes() {
 
 	// File storage (MinIO)
 	groupV1.Get("/files/url", a.authMiddleware, h.GetFileURL)
+	groupV1.Post("/files/refresh-url", a.authMiddleware, h.RefreshFileURL)
 	groupV1.Post("/files/upload", a.authMiddleware, h.UploadMedia)
 	groupV1.Post("/files/audio", a.authMiddleware, h.UploadAudio)
 	groupV1.Post("/questions/audio-answer", a.authMiddleware, h.SubmitAudioAnswer)