Maestrox OCR - PDF pages to Vercel Blob

This app does the following:

1. Upload a PDF from the browser.
2. Convert each PDF page to a separate PNG on the client side.
3. Upload each PNG directly from the browser to Vercel Blob.
4. Show a page-by-page uploaded URL list.

Requirements

• Node.js 18+
• A Vercel project with a Blob store
• BLOB_READ_WRITE_TOKEN from that project
• A public Vercel Blob store for direct browser uploads

Setup

1. Install dependencies:

npm install

2. Create your local env file:

cp .env.example .env

3. Paste your token into .env:

BLOB_READ_WRITE_TOKEN=...

4. Start the app:

npm run dev

5. Open:

• http://localhost:3000

How client-side upload works

• Browser converts PDF pages to PNG with PDF.js.
• Browser uploads files using upload() from @vercel/blob/client.
• A small server route (/api/blob/upload) only issues short-lived upload tokens.
• File bytes do not pass through your Express server.

Important note

For production, add auth/authorization checks in /api/blob/upload before issuing upload tokens.

Direct upload limitation

This implementation uses Vercel Blob client uploads, which currently require access: "public".

If your Blob store is private:

• Direct browser uploads will fail.
• The browser may only show a generic CORS or failed fetch error.
• You must either change the Blob store to public or change the app to upload through your server instead.