LibraryMS

Overview

LibraryMS is a multi-branch library circulation and cataloging platform architected to manage distributed book inventories, lending lifecycles, patron reservations, and automated overdue fine calculations. The project features a modular ASP.NET Core 9 backend and an Angular client, supported by containerized PostgreSQL services for reproducible environments.

The Problem & System Requirements

Modern distributed libraries encounter operational complexity when sharing catalog and inventory records across physical locations:

• Multi-Branch Tracking: Multiple branches hold distinct physical copies of titles with independent checkout states and availability statuses.
• Lending Rule Compliance: Borrowing limits, duration windows, and fine policies must be enforced consistently across all lending transactions.
• Reservation Queuing: Patrons reserving unavailable titles require priority-ordered queues that trigger availability notices upon return.

Architecture & Technical Decisions

The system is designed with domain isolation and containerized deployment at its core:

+-------------------------------------------------------------+
|                     Angular 14 Client                       |
|           (Circulation Desk, Patron Search, Admin UI)       |
+------------------------------+------------------------------+
                               | HTTPS REST Endpoints
+------------------------------v------------------------------+
|                   ASP.NET Core 9 Web API                    |
|       +---------------------------------------------+       |
|       |         Multi-Branch Circulation Engine     |       |
|       +---------------------------------------------+       |
|       |      Lending Rules & Automated Fine Logic   |       |
|       +---------------------------------------------+       |
|       |      Entity Framework Core Data Access      |       |
+------------------------------+------------------------------+
                               | PostgreSQL Protocol
+------------------------------v------------------------------+
|                     Dockerized PostgreSQL                   |
|       (Multi-branch catalogs, Loans, Patrons, Fines)        |
+-------------------------------------------------------------+

Key Engineering Decisions

1. Multi-Branch Inventory Modeling:
   Separating abstract title metadata (ISBN, author, publication) from physical copy entities (barcode, branch identifier, condition, status) allows seamless inter-branch tracking and inventory audits.
2. Deterministic Overdue Fine Logic:
   Fine calculations are evaluated based on business rules factoring in checkout durations, grace periods, and return timestamps, ensuring transparent accounting.
3. Docker Containerization for Reproducibility:
   Docker configurations ensure consistent development and integration environments across PostgreSQL and backend services, eliminating environment drift.

Visual Demonstration & System Diagrams

Asset Status: Both backend API and frontend client repositories are publicly available on GitHub for code inspection. Visual UI screenshots and formal branch workflow diagrams are prepared for owner sign-off.

Key Features

• Multi-Branch Cataloging: Granular catalog search across multiple branches with real-time copy availability.
• Circulation Management: Check-in, check-out, and renewal workflows with automated loan limit validations.
• Automated Fine Tracking: Calculation of overdue fees with payment status logging.
• Role-Based Security: Separate permissions for librarians, branch administrators, and members.

Engineering Takeaways

• Effective relational data modeling is crucial for preventing race conditions during concurrent book checkouts.
• Containerizing backend dependencies ensures reliable developer onboarding and integration testing.