# The Tera API

One Fastify service on `127.0.0.1:8431`, serving `/api/v1/*` behind Caddy. It
answers with flight plans, weather, a public marker snapshot and office packs,
and it does all of it with a single runtime dependency.

**It boots with no configuration at all.** No account, no Supabase project, no
API key, no network. That is not a nice property, it is the acceptance test —
`src/test/boot.test.ts` starts this server under a genuinely empty environment
and asks it for its health, and CI does the same thing from outside the
container.

```bash
npm ci                 # from the repo root; server/ is a workspace
npm start -w @lumbridge/tera-api
curl -s localhost:8431/api/v1/health | jq
```

There is no build step. Node runs the TypeScript sources directly by stripping
types at load, which needs **Node ≥ 22.18** and is why `erasableSyntaxOnly` is
set in `tsconfig.json` — an enum or a parameter property would break the runtime
without breaking the typecheck, which is the wrong order to find out.

## Routes

| route | body | cached |
| --- | --- | --- |
| `GET /api/v1/health` | `HealthBody` | never |
| `GET /api/v1/flights` | `FlightsBody` | public, `TERA_FLIGHTS_TTL` |
| `GET /api/v1/weather` | `WeatherBody` | public, `TERA_WEATHER_TTL` |
| `GET /api/v1/markers` | `MarkersBody` | public, `TERA_MARKERS_TTL` |
| `GET /api/v1/offices/:id` | `OfficeDoc` | public offices only |

Every body is declared once, in `src/server/wire.ts` in the **root** package —
type-only, so it compiles to nothing and both the browser build and this service
import the same declarations without either becoming a dependency of the other.

`Cache-Control` is fail-closed: a global hook stamps `private, no-store` on every
reply before any route runs, and a route opts in explicitly. A request that
arrived with an `Authorization` header or a cookie never gets a public policy,
whatever the route asked for.

## Configuration

Everything is `TERA_*`, everything is optional, and **nothing is fatal**. A
source configured without what it needs is demoted, not fatal: the server logs
one loud `TERA DEGRADED:` line, serves the fallback, and lists the demotion in
the `degraded` array on `/api/v1/health`. Two earlier designs failed to boot on a
missing weather contact string; this is the correction. (CONTRACT.md §5.1.)

| variable | default | what it does |
| --- | --- | --- |
| `TERA_HOST` | `127.0.0.1` | Bind address. `0.0.0.0` inside a container, nowhere else. |
| `TERA_PORT` | `8431` | |
| `TERA_LOG_LEVEL` | `info` | |
| `TERA_ORIGIN_LAT` / `_LNG` | SF | The city this box serves. Weather point and flight-plan centre. |
| `TERA_CORS_ORIGIN` | *(empty)* | Comma-separated. Empty means same-origin only. |
| `TERA_PUBLIC_MAX_AGE` | `60` | `max-age` for routes without their own TTL. |

### Weather

| variable | default | what it does |
| --- | --- | --- |
| `TERA_WEATHER_SOURCE` | `none` | `none`, `nws`, `metno`, `openmeteo`. |
| `TERA_WEATHER_CONTACT` | *(empty)* | An email or URL. Required by `nws` and `metno`. |
| `TERA_WEATHER_TTL` | `600` | Seconds between upstream fetches. |

- **`nws`** — api.weather.gov. US only, keyless, and its output is a US
  government work in the public domain, so nothing downstream of it owes anybody
  attribution. The default *once a contact is set*.
- **`metno`** — the global fallback. CC BY 4.0, so the body carries an
  `attribution` array the consumer is expected to display.
- **`openmeteo`** — opt-in and off by default. The data is CC BY 4.0, but the
  free tier is non-commercial, which is the wrong default for a product page.
  Turning it on records a line in `degraded` saying so. (CONTRACT.md §5.2.)

`none` — the default — serves a synthetic clear day with `synthetic: true`. That
is a supported steady state, not an error path.

### Flights

| variable | default | what it does |
| --- | --- | --- |
| `TERA_FLIGHTS_SOURCE` | `sim` | `sim`, `adsb`, `dump1090`. |
| `TERA_ADSB_ENDPOINT` | `https://api.adsb.lol` | Also works with airplanes.live. |
| `TERA_ADSB_RADIUS_NM` | `40` | |
| `TERA_DUMP1090_PATH` | *(empty)* | Path to your receiver's `aircraft.json`. |
| `TERA_FLIGHTS_TTL` | `300` | Clamped to 15 s for live sources. |
| `TERA_FLIGHTS_SEED` | `4711` | |

The simulated source is served as a **route plan**, not as positions: the routes,
a fixed phase origin and a seed, which every browser evaluates in closed form
against wall-clock time. One cacheable request replaces a poll per second, and
two people on different machines see the same aircraft in the same places.

There is no FlightRadar24 client and there will not be one — their terms forbid
scraping and forbid redistribution, so shipping one in an Apache-2.0 repo would
be publishing instructions for breaking a ToS. An RTL-SDR and `dump1090` on a box
you own is the best of the three sources anyway: first-party data with nothing to
comply with. (ARCHITECTURE.md §4.)

### Markers

| variable | default | what it does |
| --- | --- | --- |
| `TERA_MARKERS_SOURCE` | `none` | `none` or `file`. |
| `TERA_MARKERS_FILE` | *(empty)* | JSON snapshot written by the sync oneshot. |
| `TERA_MARKERS_PROVENANCE_ALLOWLIST` | `us-census,hand-placed,synthetic` | |
| `TERA_MARKERS_TTL` | `300` | |

The API serves a file. It holds no database and no credential, and private
per-user markers are never proxied through it — an authenticated browser calls
Workie directly with its own token, so a private row never enters this process.

**Every row must declare where its coordinate came from, and the gate refuses
anything not on the allowlist.** Serving a snapshot of geocoded coordinates is
Public Use of a Derivative Database; if those coordinates came from Nominatim,
ODbL §4.3 and §4.4 attach to everything served alongside them, no matter where
the rows are stored. Google, Mapbox and HERE are not an escape either — their
terms restrict storing and redistributing what they return. The sanctioned
geocoder is the US Census Geocoder, whose output is public domain. (CONTRACT.md
§8. Adding to the allowlist is a licence decision, not a config tweak.)

A row carrying a field the gate does not recognise is refused whole rather than
trimmed, and the refusal counts are served on the wire so a broken sync is
visible from outside instead of only in a log.

### The sync oneshot

```bash
TERA_SYNC_SOURCE_URL=https://workie.example/api/public/markers \
TERA_SYNC_TOKEN=... \
TERA_MARKERS_FILE=/var/lib/tera/markers.json \
npm run sync -w @lumbridge/tera-api
```

The only second process, and the only holder of a credential. It runs on a
timer, puts every row through the same gate, and writes the snapshot atomically.
**One refused row aborts the whole sync and leaves the previous snapshot in
place** — a stale map is a cheap mistake, and publishing coordinates whose
licence nobody can vouch for is not one that a later fix undoes.

`TERA_SYNC_PROVENANCE` asserts a provenance for rows that arrive without one.
Setting it is a licence claim you are making on the record.

### Offices and auth

| variable | default | what it does |
| --- | --- | --- |
| `TERA_OFFICES_DIR` | *(empty)* | One `<id>.json` per office. Empty means no offices. |
| `TERA_AUTH_MODE` | `none` | `none`, `sso`, `jwt`. |
| `TERA_AUTH_ENTRY_URL` | *(empty)* | Where a browser sends someone to sign in. `sso`. |
| `TERA_AUTH_REVALIDATE_URL` | *(empty)* | Server-side token check. `sso`. |
| `TERA_AUTH_COOKIE` | `tera_session` | Cookie a session may arrive in. |
| `TERA_AUTH_JWT_SECRET` | *(empty)* | HS256 shared secret. `jwt`. |
| `TERA_AUTH_JWT_VERIFY` | `hs256` | Set to `jwks` for asymmetric verification. |
| `TERA_AUTH_JWKS_URL` | *(empty)* | |
| `TERA_AUTH_JWT_ISSUER` / `_AUDIENCE` | *(empty)* | Checked when set. |

A self-hoster gets `none`, an open office, and never creates an account
anywhere. `sso` is what Lumbridge's own deployment uses: this world holds **no
credentials**, only an entry URL and a revalidate URL, and enforcement happens
here on the server.

Where a JWT is verified directly, **HS256 against a shared secret is the primary
path** and JWKS sits behind an env switch. That ordering comes from verified
fact rather than taste: the issuer this runs against signs `{"alg":"HS256"}`, and
a JWKS-only implementation would reject every real token. (CONTRACT.md §6.)

**A private office returns 404, not 403** — byte-identical to an office that was
never created — so the endpoint cannot be used to enumerate what exists. A pack
that does not declare its visibility is treated as private.

## Deploying

Three files in `../deploy`, and exactly one of each:

- `Caddyfile.snippet` — `import tera_api` into the site that serves the build.
- `tera-api.service` — systemd, with an *optional* environment file so the unit
  starts on a box where nobody wrote one.
- `docker-compose.yml` — `cd deploy && docker compose up`, under `env -i`.

## Tests

```bash
npm test -w @lumbridge/tera-api
npm run typecheck -w @lumbridge/tera-api
```

The three that are load-bearing: the empty-environment boot, the provenance
gate, and the office 404.