app/api/uploadthing/core.ts

import { currentUser } from "@clerk/nextjs";
import { createUploadthing, type FileRouter } from "uploadthing/next";

const f = createUploadthing();

const getUser = async () => await currentUser();

// FileRouter for your app, can contain multiple FileRoutes
export const ourFileRouter = {
  // Define as many FileRoutes as you like, each with a unique routeSlug
  imageUploader: f({ image: { maxFileSize: "1MB", maxFileCount: 5 } })
    // Set permissions and file types for this FileRoute
    .middleware(async (req) => {
      // This code runs on your server before upload
      const user = await getUser();

      // If you throw, the user will not be able to upload
      if (!user) throw new Error("Unauthorized");

      // Whatever is returned here is accessible in onUploadComplete as `metadata`
      return { storeId: user.privateMetadata.storeId }; // add product id metadata here too.
    })
    .onUploadComplete(async ({ metadata, file }) => {
      // This code RUNS ON YOUR SERVER after upload
      console.log("Upload complete for userId:", metadata.storeId);

      console.log("file url", file.url);
    }),
} satisfies FileRouter;

export type OurFileRouter = typeof ourFileRouter;