# uo-link — Rust sidecar

The **Rust sidecar** half of the Runic Gateway bridge. The ServUO shard dials out to this sidecar
over a loopback TCP socket (newline-delimited JSON); the sidecar owns the WebSocket + REST API the
website consumes, along with auth, buffering, and fan-out.

```
ServUO plugin (C#, net48)  ──loopback TCP, newline-JSON──►  Rust sidecar  ──WebSocket/JSON──►  website
   (RunicGateway/servuo-plugins)                           >>> THIS REPO <<<
```

The shard never speaks WebSocket and exposes no port of its own — the sidecar is the only
network-facing component, which is what keeps the game unreachable from the internet.

## Related repos

| Repo | What |
|------|------|
| **this** — `RunicGateway/link` | The Rust sidecar (`sidecar/`). |
| [RunicGateway/servuo-plugins](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins) | The **C# ServUO plugin** — the shard side of the bridge (`overlay/`, `patches/`, `deploy.ps1`, test scaffolding). |
| [RunicGateway/docs](https://gitea.whitlocktech.com/RunicGateway/docs) | All project documentation — design docs, protocol spec, integration guide, research. |

## Layout

| Path | What |
|------|------|
| `sidecar/` | The Rust sidecar crate — terminates the loopback link to the shard, exposes WS + REST to the website. See [`sidecar/README.md`](sidecar/README.md). |
| `.gitea/workflows/release.yml` | Builds + releases the sidecar binary (Linux + Windows) on every merge to `main`. |

## Build & run

The sidecar is a standard cargo crate:

```bash
cd sidecar
cargo build --release        # binary at target/release/uo-link-sidecar
cp sidecar.toml.example sidecar.toml   # then edit
cargo run --release
```

`.gitea/workflows/release.yml` cross-compiles Linux + Windows binaries and cuts a Gitea release on
every merge to `main` (conventional-commit versioning). See [`sidecar/README.md`](sidecar/README.md)
for configuration and the wire protocol.

## Deployment & compatibility

The plugin ([RunicGateway/servuo-plugins](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins))
and this sidecar are deployed **together** but built **independently**:

- The **plugin** is deployed as source into the ServUO server root and compiled by ServUO at boot —
  no build artifact, no CI build.
- The **sidecar** is a standalone Rust binary released from this repo.

The only coupling is the **loopback JSON protocol** (the shard dials `127.0.0.1`). Compatibility is a
protocol concern, not a build-order one — keep the event/command catalog in sync across the two
repos. Canonical spec:
[PLAN.md](https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/link/PLAN.md) §5/§7 and
[INTEGRATION.md](https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/link/INTEGRATION.md).
Because a wedged or absent sidecar cannot stall the shard, either side can be deployed or restarted
independently.