SkillShare — Non-Functional Requirements Specification

These requirements are derived from the released architecture and implementation of the Milestone 4 system.

NFR-01 Security

• ID: NFR-01
• Requirement: All communication must be securely authenticated and authorized, with user passwords securely hashed.
• Implementation Evidence: JWT-based stateless authentication (AuthTokenFilter.java), BCrypt password hashing (SecurityConfig.java), zero-trust WebSocket validation (ChatAuthorizationService.java).
• Verification Method: Verified via automated backend security tests, API Postman suites, and manual JWT manipulation attempts.

NFR-02 Performance

• ID: NFR-02
• Requirement: The system shall respond to typical user interactions swiftly to ensure a smooth user experience.
• Implementation Evidence: Frontend optimizations using React Vite, pagination implemented on backend listing endpoints (Pageable in Spring Data JPA).
• Verification Method: Qualitative manual QA and execution of the API regression suite.

NFR-03 Reliability

• ID: NFR-03
• Requirement: The system shall process complex state changes reliably without leaving the application in an inconsistent state.
• Implementation Evidence: Database transactions (@Transactional in SessionService.java and GamificationService.java) ensuring atomic credit deduction, session booking, and notification dispatch.
• Verification Method: Verified via JUnit testing specifically targeting transaction failures (e.g., testBookSession_InsufficientCredits).

NFR-04 Maintainability

• ID: NFR-04
• Requirement: The codebase must be structured cleanly to facilitate future enhancements and debugging.
• Implementation Evidence: Strict layered architecture (Controller -> Service -> Repository), separated frontend API client mapping (src/api), and use of explicit DTOs over entity serialization.
• Verification Method: Verified via code review and architectural audits (docs/mission-19F-12-report.md).

NFR-05 Scalability

• ID: NFR-05
• Requirement: The architecture must support stateless horizontal scaling of the API servers.
• Implementation Evidence: Stateless REST API design, JWT usage eliminating server-side session replication, externalized PostgreSQL database.
• Verification Method: Architectural verification (the system inherently avoids HttpSession).

NFR-06 Usability

• ID: NFR-06
• Requirement: The user interface shall be intuitive, responsive, and provide clear error feedback.
• Implementation Evidence: Centralized error normalization (GlobalExceptionHandler.java), localized client-side toasts, and responsive design utilizing Tailwind CSS.
• Verification Method: Verified via Manual QA across different viewport sizes.

NFR-07 Compatibility

• ID: NFR-07
• Requirement: The application must operate across standard modern web browsers.
• Implementation Evidence: Vite and React 18 configuration targeting modern browsers.
• Verification Method: Manual QA and Vitest baseline suite.

NFR-08 Data Integrity

• ID: NFR-08
• Requirement: The system must enforce strong relational consistency and data constraints.
• Implementation Evidence: PostgreSQL foreign keys, unique constraints (e.g., sender_id, receiver_id in CONNECTION), and JPA Bean Validation annotations (@NotNull, @Size).
• Verification Method: Backend integration tests asserting constraint violations.

NFR-09 Testability

• ID: NFR-09
• Requirement: Core business logic must be structurally testable in isolation.
• Implementation Evidence: Dependency Injection (Spring IoC) allowing mock injection in services (e.g., Mockito in SessionServiceTest.java).
• Verification Method: Verified through the automated JUnit 5 backend test suite executed during release QA.

NFR-10 Configurability and Deployment

• ID: NFR-10
• Requirement: The system must externalize environment-specific configurations.
• Implementation Evidence: application.yml profiles in Spring Boot and .env variables (VITE_API_URL) in the Vite frontend.
• Verification Method: Verified by successful local and remote environment toggling during QA.