docs: Added agents file to support ai assisted coding

2026-02-20 21:50:21 +01:00
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+# AGENTS.md — LfK Backend
+
+Guidance for agentic coding agents working in this repository.
+
+---
+
+## Project Overview
+
+Express + [`routing-controllers`](https://github.com/typestack/routing-controllers) REST API written in TypeScript. Uses TypeORM for database access (SQLite in dev/test, PostgreSQL or MySQL in production). OpenAPI docs are auto-generated from decorators at startup.
+
+**Runtime & Package Manager**: Bun (replaces Node.js + npm/pnpm).
+
+---
+
+## Build / Run / Test Commands
+
+### Development
+
+```sh
+bun run dev           # Start dev server with auto-reload (uses Bun's --watch)
+```
+
+**Auto-reload**: The `dev` script uses Bun's built-in `--watch` flag, which automatically restarts the server when TypeScript files in `src/` change. Bun runs TypeScript directly - no build step needed.
+
+**Performance**: Bun delivers 8-15% better latency under concurrent load compared to Node.js. See `BUN_BENCHMARK_RESULTS.md` for details.
+
+### Build
+
+```sh
+bun run build         # rimraf dist && tsc && copy static assets → dist/
+```
+
+**Note**: The build script exists for legacy compatibility and type-checking, but is **not required** for development or production. Bun runs TypeScript source files directly.
+
+### Production
+
+```sh
+bun start             # bun src/app.ts (runs TypeScript directly)
+```
+
+### Tests
+
+Tests are **integration tests** that hit a live running server via HTTP. The server must be started before Jest is invoked.
+
+```sh
+# Full CI test flow (generates .env, starts server, runs jest):
+bun run test:ci
+
+# Run Jest directly (server must already be running):
+bun test
+
+# Watch mode:
+bun run test:watch
+
+# Run a single test file:
+bunx jest src/tests/runners/runner_add.spec.ts
+
+# Run tests matching a name pattern:
+bunx jest --testNamePattern="POST /api/runners"
+
+# Run all tests in a subdirectory:
+bunx jest src/tests/runners/
+```
+
+# Run all tests in a subdirectory:
+bunx jest src/tests/runners/
+```
+
+> **Important:** `bun test` alone will fail unless the dev server is already running on `http://localhost:<config.internal_port>`. In CI, `start-server-and-test` handles this automatically via `bun run test:ci`.
+
+### Other Utilities
+
+```sh
+bun run seed                 # Sync DB schema and run seeders
+bun run openapi:export       # Export OpenAPI spec to file
+bun run docs                 # Generate TypeDoc documentation
+bun run licenses:export      # Export third-party license report
+```
+
+---
+
+## TypeScript Configuration
+
+- **Target:** ES2020, **Module:** CommonJS
+- **`strict: false`** — TypeScript strictness is disabled; types are used but not exhaustively enforced
+- **`experimentalDecorators: true`** and **`emitDecoratorMetadata: true`** — required by `routing-controllers`, `TypeORM`, and `class-validator`
+- Spec files (`**/*.spec.ts`) are excluded from compilation
+- Source root: `src/`, output: `dist/`
+
+---
+
+## Code Style Guidelines
+
+### No Linter / Formatter Configured
+
+There is no ESLint or Prettier configuration. Follow the patterns already established in the codebase rather than introducing new tooling.
+
+### Imports
+
+- Use named imports for decorator packages: `import { Get, JsonController, Param } from 'routing-controllers'`
+- Use named imports for TypeORM: `import { Column, Entity, getConnectionManager } from 'typeorm'`
+- Use named imports for class-validator: `import { IsInt, IsOptional, IsString } from 'class-validator'`
+- Use `import * as X from 'module'` for modules without clean default exports (e.g., `import * as jwt from 'jsonwebtoken'`)
+- Use default imports for simple modules (e.g., `import cookie from 'cookie'`)
+- `reflect-metadata` is imported once at the top of `src/app.ts` — do not re-import it
+- No barrel/index re-export files; import source files directly by path
+
+### Naming Conventions
+
+| Construct | Convention | Example |
+|---|---|---|
+| Classes | `PascalCase` | `RunnerController`, `CreateRunner` |
+| Files | `PascalCase.ts` matching class name | `RunnerController.ts` |
+| Local variables | `camelCase` (some `snake_case` in tests) | `accessToken`, `access_token` |
+| DB entity fields | `snake_case` preferred | `created_at`, `updated_at` |
+| Controller methods | REST-conventional | `getAll`, `getOne`, `post`, `put`, `remove` |
+| Custom errors | `{Entity}{Issue}Error` | `RunnerNotFoundError`, `RunnerIdsNotMatchingError` |
+| Response DTOs | `Response{Entity}` | `ResponseRunner`, `ResponseAuth` |
+| Create DTOs | `Create{Entity}` | `CreateRunner` |
+| Update DTOs | `Update{Entity}` | `UpdateRunner` |
+| Enums | `PascalCase` | `ResponseObjectType`, `PermissionAction` |
+
+### Formatting
+
+- 4-space indentation (observed throughout the codebase)
+- Single quotes for string literals in most files
+- No trailing semicolons style inconsistency — follow what's already in the file you're editing
+
+### Types
+
+- Add TypeScript types to all function parameters and return values
+- Use `class-validator` decorators (`@IsString`, `@IsInt`, `@IsOptional`, `@IsUUID`, etc.) on every DTO and response class field — these drive both runtime validation and OpenAPI schema generation
+- Use abstract classes for shared entity base types (e.g., `abstract class Participant`)
+- Use interfaces for response contracts (e.g., `interface IResponse`)
+- Use enums for typed string/number constants
+- Avoid `any` where possible; when unavoidable, keep it localised
+- `strict` is off — but still annotate types explicitly rather than relying on inference
+
+### Controller Pattern
+
+```typescript
+import { Authorized, Body, Delete, Get, JsonController, Param, Post, Put } from 'routing-controllers';
+import { OpenAPI, ResponseSchema } from 'routing-controllers-openapi';
+
+@JsonController('/runners')
+@Authorized()
+export class RunnerController {
+    @Get('/')
+    @OpenAPI({ description: 'Returns all runners' })
+    @ResponseSchema(ResponseRunner, { isArray: true })
+    async getAll() { ... }
+
+    @Get('/:id')
+    @ResponseSchema(ResponseRunner)
+    async getOne(@Param('id') id: number) { ... }
+
+    @Post('/')
+    @ResponseSchema(ResponseRunner)
+    async post(@Body({ validate: true }) createRunner: CreateRunner) { ... }
+
+    @Put('/:id')
+    @ResponseSchema(ResponseRunner)
+    async put(@Param('id') id: number, @Body({ validate: true }) updateRunner: UpdateRunner) { ... }
+
+    @Delete('/:id')
+    @ResponseSchema(ResponseRunner)
+    async remove(@Param('id') id: number) { ... }
+}
+```
+
+### Error Handling
+
+- Define custom error classes in `src/errors/` extending `routing-controllers` error types (`NotFoundError`, `NotAcceptableError`, etc.)
+- Every custom error class must include `@IsString()` decorated `name` and `message` fields for OpenAPI schema generation
+- Throw custom errors directly in controllers: `throw new RunnerNotFoundError()`
+- Use try/catch in controllers and re-throw meaningful errors; do not swallow errors silently
+- The global `ErrorHandler` middleware (registered in `src/middlewares/`) catches all unhandled errors and serialises them as JSON — do not duplicate this logic in controllers
+- Auth errors are thrown from `src/middlewares/authchecker.ts`, not from individual controllers
+
+### Entity Pattern (TypeORM)
+
+- Entities live in `src/models/entities/`
+- Decorate every entity with `@Entity()` and every column with the appropriate `@Column`, `@PrimaryGeneratedColumn`, etc.
+- Use `@CreateDateColumn()` / `@UpdateDateColumn()` for timestamp fields
+- Use table inheritance (`@TableInheritance` + `@ChildEntity`) for polymorphic entities
+- Access repositories via `getConnectionManager().get().getRepository(EntityClass)` — do not inject repositories as constructor dependencies
+- Database schema is synchronised automatically on startup (`connection.synchronize()`) — no manual migration files
+
+### DTO Pattern (Create / Update)
+
+- Create DTOs in `src/models/actions/create/` and `src/models/actions/update/`
+- Use `class-validator` decorators for every field
+- `@IsOptional()` for fields that are not required on update; all fields on create DTOs should be mandatory unless explicitly optional in the API contract
+- Response DTOs live in `src/models/responses/` and follow the `Response{Entity}` naming pattern
+
+---
+
+## Test Style Guidelines
+
+> **IMPORTANT: Do not run existing tests and do not create new tests.** The existing test suite in `src/tests/` is outdated and no longer reflects the current state of the codebase. Ignore all test files when working in this repository. Do not write new tests for any changes or additions.
+
+All tests are integration tests in `src/tests/` organised by domain entity:
+
+```
+src/tests/
+  auth/
+    auth_login.spec.ts
+    auth_refresh.spec.ts
+  runners/
+    runner_add.spec.ts
+    runner_get.spec.ts
+    runner_update.spec.ts
+    runner_delete.spec.ts
+  ...
+```
+
+### Test File Template
+
+```typescript
+import axios from 'axios';
+import { config } from '../../config';
+const base = "http://localhost:" + config.internal_port;
+
+let access_token: string;
+let axios_config: object;
+
+beforeAll(async () => {
+    jest.setTimeout(20000);
+    const res = await axios.post(base + '/api/auth/login', { username: "demo", password: "demo" });
+    access_token = res.data["access_token"];
+    axios_config = {
+        headers: { "authorization": "Bearer " + access_token },
+        validateStatus: undefined   // prevents axios from throwing on non-2xx responses
+    };
+});
+
+describe('POST /api/runners working', () => {
+    it('creating a runner with required params should return 200', async () => {
+        const res = await axios.post(base + '/api/runners', { ... }, axios_config);
+        expect(res.status).toEqual(200);
+        expect(res.headers['content-type']).toContain("application/json");
+    });
+});
+
+describe('POST /api/runners failing', () => {
+    it('creating a runner without required params should return 400', async () => {
+        const res = await axios.post(base + '/api/runners', {}, axios_config);
+        expect(res.status).toEqual(400);
+    });
+});
+```
+
+- Always set `validateStatus: undefined` in `axios_config` to prevent axios throwing on error responses
+- Group tests by HTTP verb + route in `describe()` blocks; separate "working" and "failing" cases
+- Use `jest.setTimeout(20000)` in `beforeAll` for slow integration tests
+- Assert both `res.status` and `res.headers['content-type']` on success paths
+
+---
+
+## Environment Configuration
+
+- Copy `.env.example` to `.env` and fill in values before running locally
+- Database type is set via `DB_TYPE` env var (`sqlite`, `postgres`, or `mysql`)
+- Server port is set via `INTERNAL_PORT` (accessed as `config.internal_port` in code)
+- All config values are validated at startup in `src/config.ts`
+- CI env is generated by `bun run test:ci:generate_env` (`scripts/create_testenv.ts`)
+
+### NATS Configuration
+
+The backend uses **NATS JetStream** as a KV cache for scan intake performance optimization.
+
+- `NATS_URL` — connection URL for NATS server (default: `nats://localhost:4222`)
+- `NATS_PREWARM` — if `true`, preloads all runner state into the KV cache at startup to eliminate DB reads from the first scan onward (default: `false`)
+
+**KV buckets** (auto-created by `NatsClient` at startup):
+- `station_state` — station token cache (1-hour TTL)
+- `card_state` — card→runner mapping cache (1-hour TTL)
+- `runner_state` — runner display name, total distance, latest scan timestamp (no TTL, CAS-based updates)
+
+**Development**: NATS runs in Docker via `docker-compose.yml` (port 4222). The JetStream volume is persisted to `./nats-data/` to survive container restarts.
+
+**Station intake hot path**: `POST /api/scans/trackscans` from scan stations uses a KV-first flow that eliminates DB reads on cache hits and prevents race conditions via compare-and-swap (CAS) updates. See `SCAN_NATS_PLAN.md` for full architecture details.