Architecture

Shelf-School is a server-rendered Django application with a public circulation surface and authenticated staff operations.

Browser camera or uploaded image
  -> Django form and local barcode decoder
  -> Book / Copy lookup
  -> signed confirmation token
  -> transactional Loan update
  -> SQLite database

Domain model

Model	Purpose
SchoolProfile	Singleton branding and loan defaults.
Book	Bibliographic title or edition.
Copy	One physical item with a unique QR payload.
Borrower	Student or teacher who can receive books.
Loan	Checkout, due date, and optional return date for one copy.

The database enforces one active loan per physical copy.

Trust boundaries

The root circulation route is intentionally public for a supervised school kiosk. Catalog, borrowers, reports, backups, settings, and Django administration require authentication. Named recent activity is not rendered for signed-out users.

Photo identification does not mutate circulation state. It creates a signed, short-lived confirmation token containing copy, borrower, action, and due date. The confirmation request locks and revalidates the copy before changing the loan, protecting against stale or repeated submissions.

Storage and external services

• SQLite is the default structured store.
• Uploaded files use local media storage.
• zxing-cpp decodes QR and ISBN barcodes locally.
• Open Library is queried only for optional ISBN metadata during intake.
• No paid AI service is required.