Library Catalog

A multi-tenant library catalog application with token-based authentication and asynchronous book reservations. Each organization (library) manages its own members and loans in isolation, while sharing a common book catalog.

Architecture

frontend/       React 19 + TypeScript + TanStack Router/Query (Vite)
backend/        .NET 10 / ASP.NET Core / EF Core / PostgreSQL 18
python-tools/   Python CLI tool for generating overdue-loan reports

The backend exposes a REST API covering books, members, loans, overdue loans, and reservations. Authentication is handled via a login endpoint that returns a JWT-style bearer token; all endpoints except the book listing require authentication.

A background worker runs inside the API process and periodically confirms pending book reservations. When a reservation is created it starts in Pending status; a moment later (roughly 1--2 seconds) the background process picks it up and transitions it to Confirmed (or Rejected if no copies are available).

Tenant isolation is enforced server-side: each authenticated request is scoped to the user's organization, so members of one library cannot see another library's loans, reservations, or member data.

The frontend consumes the API via TanStack Query. All three services are wired together with Docker Compose.

Running the application

docker compose up --build

Service	URL
API	http://localhost:8080
Web UI	http://localhost:3000

The Python reporting tool runs on demand:

docker compose run --rm python-tools

Or bring it up with the tools profile:

docker compose --profile tools up --build

Demo accounts

The database is seeded with the following users on first startup. All accounts use the password P@ssw0rd.

Default Library

Name	Email
Alice Johnson	alice@example.com
Bob Smith	bob@example.com
Carol Williams	carol@example.com

Northgate Library

Name	Email
Dave Martinez	dave@northgate.com
Eve Thompson	eve@northgate.com

Running tests

Backend (.NET)

dotnet test backend/Catalog.slnx

Frontend (Playwright E2E)

Bring the stack up first, then run the E2E suite. Playwright's browsers run in a version-matched Docker container driven from the host, so this works on Arch/Linux without installing browser system dependencies:

docker compose up -d --build
./scripts/e2e.sh                 # run every spec
./scripts/e2e.sh reservation     # or scope to one spec

scripts/e2e.sh starts a Playwright server container, connects the host test runner to it over a WebSocket, and removes the container when finished.

Python tools

cd python-tools
pip install -e ".[dev]"
pytest

Notes

• Loan due dates are calculated relative to a fixed reference date, so the overdue-loan count is deterministic regardless of when the application is started.
• Automated test coverage is currently minimal -- just a handful of smoke tests to verify the stack boots and serves data. Both the backend test harness (Testcontainers-based CatalogApiFactory) and the Playwright configuration are in place and ready to be extended.