---
type: architecture
title: Key Files Index
description: One-line responsibility for important source files, including authenticated event streaming.
tags: [architecture, index, key-files]
timestamp: 2026-07-22T10:32:00Z
---

# Backend

| File | Responsibility |
|---|---|
| `backend/src/main.ts` | Bootstraps Nest, middleware, OpenAPI, static assets, and SPA fallback. |
| `backend/src/app.module.ts` | Wires feature modules and global providers. |
| `backend/src/database/database.module.ts` | Configures TypeORM with SQLite. |
| `backend/src/database/database-init.service.ts` | Initializes the database and runs migrations. |
| `backend/src/common/guards/jwt-auth.guard.ts` | Global JWT authorization guard. |
| `backend/src/common/middleware/csrf.middleware.ts` | Double-submit CSRF protection. |
| `backend/src/common/services/event-status.service.ts` | Computes the event-window state machine. |
| `backend/src/common/services/sse-hub.service.ts` | In-process pub/sub for server-sent event streams. |
| `backend/src/modules/system/system.controller.ts` | Registers bootstrap, event status, settings, and SSE endpoints. |
| `backend/src/modules/system/system.service.ts` | Builds the public bootstrap payload. |
| `backend/src/modules/auth/auth.controller.ts` | Registers authentication and account endpoints. |
| `backend/src/modules/auth/auth.service.ts` | Handles sessions, authentication, registration, and password changes. |

# Frontend

| File | Responsibility |
|---|---|
| `frontend/src/main.ts` | Bootstraps Angular and registers HTTP interceptors. |
| `frontend/src/app/app.routes.ts` | Defines public, shell, child, and admin routes. |
| `frontend/src/app/app.component.ts` | Loads bootstrap data and restores the session. |
| `frontend/src/app/features/home/home.component.ts` | Authenticated shell container; starts user and event state services. |
| `frontend/src/app/core/services/auth.service.ts` | Signal-backed access token and current-user state; owns the cross-tab invalidation `BroadcastChannel` + `storage`-event fallback. |
| `frontend/src/app/core/services/auth-session-events.pure.ts` | Pure cross-tab message encoding/validation and namespaced constants used by the auth broadcast channel. |
| `frontend/src/app/core/services/authenticated-event-source.service.ts` | Fetch-based authenticated SSE transport with frame parsing, abort support, and a separate `'unauthorized'` event for `401`/`403`. |
| `frontend/src/app/core/services/event-status.store.ts` | Event state signal store, one-second countdown timer, and the optional `onUnauthorized` callback wiring. |
| `frontend/src/app/core/services/event-status.pure.ts` | Event payload types, transport interface (including `'unauthorized'` listener), pure countdown helpers, and the `LED_COLOR_BY_STATE` map used by the shell LED. |
| `frontend/src/app/features/home/home.component.ts` | Authenticated shell container; starts user and event state services, subscribes to peer invalidation, and navigates to `/login` when the session is invalidated elsewhere. |
| `frontend/src/app/features/shell/header/shell-header.component.ts` | Shell title, status LED (size/shape only — color comes from the pure map via `[style.background-color]`), countdown, and user menu. |
| `frontend/src/app/features/shell/tabs/quick-tabs.component.ts` | Main shell navigation tabs. |
| `frontend/src/app/features/shell/change-password/change-password-modal.component.ts` | Change-password form modal. |
| `tests/frontend/authenticated-event-source.spec.ts` | Tests SSE authorization, frame transport behavior, and the `401`/`403` unauthorized path. |
| `tests/frontend/auth-session-events.spec.ts` | Pure tests for cross-tab invalidation message encoding, payload validation, and `storage`-event filtering. |

# See also

- [Frontend Structure](/architecture/frontend-structure.md)
- [Authenticated Shell](/guides/authenticated-shell.md)
- [System Endpoints](/api/system.md)