Cross-Cutting Concerns

Cross-cutting concerns apply to multiple components of the system and ensure reliability, security, and maintainability.

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Security

Security is enforced across all layers of the system.

The following mechanisms are implemented:

• Role-Based Access Control (RBAC)
  Users are assigned roles (Student, Teacher, Admin), and permissions are enforced accordingly.

• Authentication for Protected Endpoints
  All protected API routes require a valid authentication token.

• Admin-Only Route Restrictions
  Administrative actions (e.g., deleting quizzes, deleting student data) are restricted via backend middleware checks.

• Secure Communication (HTTPS)
  All client-server communication occurs over encrypted HTTPS connections.

• Sandboxed Code Execution
  Student code is executed in an isolated environment with resource limits to prevent system compromise.

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Logging

All meaningful system interactions are recorded to ensure traceability and analytics support.

The system logs:

• Suggestion selections stored in the suggestion_events table
• Code submissions stored in the submissions table
• Administrative actions recorded in the event_logs table
• System errors captured for debugging and monitoring

Logging ensures:

• Accountability
• Auditability
• Performance analysis
• Debugging support

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Performance

System performance is optimized using the following strategies:

• Indexed database queries for fast lookups
• Asynchronous AI calls to prevent blocking
• Asynchronous code runner execution
• Separation of services to reduce coupling

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Exception Handling

The system includes structured error handling at all architectural layers.

• Backend API routes return standardized HTTP status codes (200, 400, 401, 403, 500).
• Validation errors are handled before business logic execution.
• AI service timeouts return graceful fallback responses.
• Code Runner failures (compile errors, runtime errors, timeouts) are captured and returned safely.
• All critical exceptions are logged in the event_logs table.

This ensures predictable system behavior and improved debugging capability.

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Initialization and Reset

The system supports proper initialization and recovery mechanisms:

• Backend services initialize database connections at startup.
• Environment variables configure external dependencies.
• Code Runner containers are initialized per execution and destroyed afterward.
• Database migrations ensure schema consistency.
• Application restart does not corrupt persistent data.

This guarantees stability across deployments and restarts.

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Memory Management

Memory management is addressed through:

• Resource-limited sandbox execution for Code Runner.
• Timeout thresholds on AI and execution requests.
• Automatic garbage collection provided by the runtime (Python / Node.js).
• Avoidance of long-lived in-memory state on the backend.

This prevents resource exhaustion and denial-of-service risks.

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Internationalization

The current system is designed in English.

Future internationalization can be supported by:

• Externalizing UI strings.
• Language-based configuration.
• UTF-8 encoding support in database and API responses.

The architecture does not restrict future multi-language support.

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Built-in Help

The system supports user guidance through:

• Inline explanations for AI suggestions.
• Dashboard feedback messages.
• Validation error messages.
• Contextual tooltips in the user interface.

Future versions may include:

• Interactive tutorials.
• Help documentation pages.
• Onboarding walkthroughs.

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Built-in Test Facilities

Testing support is incorporated at multiple layers:

• Unit testing of backend services.
• API endpoint testing.
• Code Runner validation against predefined test cases.
• Logging system for auditing behavior.
• Automated frontend component testing.

These facilities ensure system reliability and regression prevention.