Campus URP
7-Subsystem Enterprise URP & Asynchronous Systems Architecture
The Engineering Problem
An enterprise-grade, modular monolith University Resource Planning (URP) suite spanning 7 master subsystems—automated academic scheduling (CP-SAT + DFS solvers), digital cafe wallet & POS, integrated library & OPAC, campus societies, lost & found mediation, help desk ticketing, and stateful identity management.
- ▶Zero faculty/room/cohort double-booking enforced via CP-SAT hard constraints and bitmask pre-computation.
- ▶ACID row-level locking for zero-trust cafe POS double-spend prevention.
- ▶Strict RBAC enforcement across Student, Faculty, and 7 module-scoped admin roles (Timetable, Library, Societies, Lost & Found, Help Desk, Cafe, Super Admin).
Single deployment unit with strict module boundaries avoids distributed system overhead (service mesh, eventual consistency) while maintaining sub-module isolation across 7 subsystems.
Non-blocking I/O via native binary protocol driver handles concurrent BFF dashboard aggregations, real-time WebSocket broadcasting, and financial row-level locks without thread pool saturation.
Guarantees mathematically optimal constraint satisfaction using interval variables and NoOverlap constraints for room, faculty, and cohort conflict resolution under a strict 2-minute solver timeout.
PostgreSQL-tracked refresh tokens enable instant session revocation and Token Theft Reuse Detection — if a revoked token is presented, all active sessions for that user are purged.
HOVER NODES TO INSPECT SERVICE BOUNDARIES AND IMPLEMENTATION DETAILS
Next.js / TypeScript / Tailwind CSS
Nginx / Docker Compose
FastAPI / Python / Uvicorn
Google OR-Tools / CP-SAT
PostgreSQL / Async SQLAlchemy
SMTP / ReportLab / OpenPyXL
App Router shell serving student, faculty, and 7 module-scoped admin portals with TanStack Query data fetching.
7 MASTER SUBSYSTEMS — 40+ DATABASE TABLES — 250+ API ENDPOINTS
Hybrid Roll No/Email identity with stateful JWT Refresh Token Rotation, RBAC enforcement, and Zero Information Leakage password recovery.
CP-SAT constraint solver and recursive backtracking DFS with O(1) bitmask caches, manual builder planner, and Time Travel dashboard.
Role-based mini social network with dual-channel chat (General/Executive), membership lifecycle state machine, and Admin Oversight Mode.
Unified Inventory Architecture separating Book metadata from physical BookCopy assets, with automated Waitlist/Hold-Shelf routing and late-fee financials.
Verified crowdsourcing platform with moderation-first triage, multi-party claim mediation engine, and edit-locking on approved items.
Digital wallet and cash-hybrid POS with Smart Classification (Payment vs Loan), row-level locks (SELECT FOR UPDATE), and Digital Kitchen Display System.
Enterprise facility ticketing across 6 domains (IT, Maintenance, Electrical, Plumbing, Furniture, Other) with SLA severity tiers, War Room hourly ticket heatmap analytics, and custom SQL priority sorting.
Constraint-Based Timetable Optimization
Manual scheduling across shared building pools consumed 1.5 days of administrative labor per semester for the largest departments, with frequent room and cohort conflicts.
Integrated dual-mode automated scheduling: Google OR-Tools CP-SAT solver (2-minute timeout) for optimal placement, and recursive backtracking DFS (200K node cap) for rapid conflict-free generation.
Cross-Module State Machine Integrity
Multiple subsystems (Help Desk, Lost & Found, Library, Cafe POS) each manage independent lifecycles with strict transition rules that must prevent invalid state mutations.
Implemented server-enforced state machine guardrails: Help Desk tickets lock editing once review starts, Lost & Found items lock critical fields once approved, and Library holds expire after 48-hour pickup windows.
Zero-Trust Financial Engine & Concurrency
Concurrent cafeteria checkouts risked race conditions and balance overdrafts during peak meal hours across hundreds of simultaneous users.
Engineered PostgreSQL row-level locks (SELECT FOR UPDATE) on wallet rows with 5-second idempotency deduplication, zero-trust server-side price recalculation, and automated defaulter ban logic.