BookLib server operators can create a library-level QR code for the BookLib App Clip. Encode the public HTTPS server URL as the server query parameter:

https://clip.booklib.cloudstarsoftware.com/open?server=https%3A%2F%2Fbooks.example.com

The App Clip opens the named server, requests a temporary guest session, scans the ISBN barcode on a book, and asks for the borrower’s name before checkout.

The server must:

  • Be reachable through HTTPS with a valid public certificate
  • Serve BookLib from the origin root, not from a URL subpath
  • Run a BookLib release that supports App Clip guest checkout
  • Have GUEST_ACCESS_ENABLED=true
  • Set GUEST_SHELF_ACCESS_ENABLED=true to show the visual bookshelf

Users without App Clip support see a confirmation page before continuing to the server’s normal web interface.

For Apple App Clip Codes, which have a small URL payload, BookLib uses short aliases on c.cloudstarsoftware.com:

https://c.cloudstarsoftware.com/p

The p alias opens the production BookLib server. The longer /open?server= form remains available for ordinary QR codes and arbitrary self-hosted servers.

The invocation service is stateless. The server address stays in the QR URL; the service does not store server registrations, credentials, tokens, library contents, or borrower information.

Deploying the invocation Worker

  1. Create a Cloudflare Worker using infrastructure/app-clip-worker.js in module-worker mode.
  2. Add the custom domain clip.booklib.cloudstarsoftware.com. Add c.cloudstarsoftware.com to the same Worker for short App Clip Codes.

  3. Confirm that both association URLs return JSON directly with no redirect:

    https://clip.booklib.cloudstarsoftware.com/apple-app-site-association
https://clip.booklib.cloudstarsoftware.com/.well-known/apple-app-site-association
  4. Test an invocation URL in a browser and confirm that it displays the destination hostname before offering to continue.

The Worker can be tested locally with Node.js:

node --test infrastructure/app-clip-worker.test.mjs