OwnCord/docs/protocol.md

# WebSocket Protocol Reference

All client-server real-time communication happens over a single WebSocket connection. Messages are JSON with a `type` and `payload`.

**Related docs:**
- [api.md](api.md) -- REST endpoints (message history, file uploads, etc.)
- [schema.md](schema.md) -- Database tables and permission bitfields

---

## Table of Contents

1. [Transport Layer](#transport-layer)
2. [Message Envelope](#message-envelope)
3. [Sequence Numbers](#sequence-numbers)
4. [Authentication Flow](#authentication-flow)
5. [Heartbeat and Connection Liveness](#heartbeat-and-connection-liveness)
6. [Reconnection with State Recovery](#reconnection-with-state-recovery)
7. [Initial State (ready)](#initial-state-ready)
8. [Chat Messages](#chat-messages)
9. [Reactions](#reactions)
10. [Typing Indicators](#typing-indicators)
11. [Presence](#presence)
12. [Channel Focus](#channel-focus)
13. [Channel Updates](#channel-updates)
14. [Member Updates](#member-updates)
15. [Voice Signaling](#voice-signaling)
16. [Direct Messages](#direct-messages)
17. [Server Restart](#server-restart)
18. [Error Handling](#error-handling)
19. [Rate Limits](#rate-limits)
20. [Message Type Reference Table](#message-type-reference-table)

---

## Transport Layer

### WebSocket Endpoint

```
wss://{host}/api/v1/ws
```

The client connects via the Tauri Rust backend's WS proxy rather than native WebView2 WebSocket. This is required because WebView2 rejects self-signed TLS certificates. The Rust proxy uses TOFU (Trust On First Use) certificate pinning.

### Transport Limits

| Limit | Value |
|-------|-------|
| Max read size | 1 MB |
| Max message content | 4000 runes |
| Write timeout | 10 seconds |
| Auth deadline | 10 seconds |
| Send buffer per client | 256 messages |

---

## Message Envelope

Every WebSocket message is a JSON object with these fields:

```json
{
  "type": "message_type",
  "id": "unique-request-id",
  "payload": { },
  "seq": 42
}
```

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `type` | string | Yes | Determines how `payload` is interpreted |
| `id` | string | Client messages only | Client-generated UUID for request/response correlation |
| `payload` | object | Yes | Contents vary by `type`. Must be present (can be `{}`). |
| `seq` | uint64 | Broadcast messages only | Monotonically increasing sequence number. Only present on server-to-client broadcast messages. |

---

## Sequence Numbers

The sequence number system enables reconnection with state recovery.

1. The server maintains an atomic `uint64` counter.
2. Every broadcast message gets the next seq number.
3. The message is stored in a 1000-event replay ring buffer.
4. The client tracks `lastSeq` from every server broadcast.

### Which Messages Get seq

| Category | Has seq? | Examples |
|----------|----------|---------|
| Channel broadcasts | Yes | `chat_message`, `chat_edited`, `chat_deleted`, `reaction_update` |
| Global broadcasts | Yes | `presence`, `member_join`, `member_leave`, `member_update`, `member_ban`, `voice_state`, `voice_leave`, `channel_create`, `channel_update`, `channel_delete`, `server_restart` |
| Ephemeral | No | `typing` |
| DM messages | No | DM `chat_message`, `chat_edited`, `chat_deleted`, `reaction_update`, `dm_channel_open`, `dm_channel_close` |
| Direct responses | No | `auth_ok`, `auth_error`, `chat_send_ok`, `error`, `voice_config`, `voice_token`, `pong` |

---

## Authentication Flow

### Step 1: Client Sends auth

After the WebSocket connection is established, the client sends the first message within 10 seconds:

```json
{
  "type": "auth",
  "payload": {
    "token": "session-token-from-login",
    "last_seq": 0
  }
}
```

| Field | Type | Required | Description |
|-------|------|----------|-------------|
| `token` | string | Yes | Session token obtained from `POST /api/v1/auth/login` |
| `last_seq` | uint64 | No | Last sequence number received. If > 0, server attempts replay. Default 0. |

### Step 2: Success -- auth_ok

```json
{
  "type": "auth_ok",
  "payload": {
    "user": {
      "id": 1,
      "username": "alex",
      "avatar": "uuid.png",
      "role": "admin"
    },
    "server_name": "My Server",
    "motd": "Welcome!"
  }
}
```

### Step 3: Failure -- auth_error

```json
{
  "type": "auth_error",
  "payload": {
    "message": "Invalid or expired token"
  }
}
```

After sending `auth_error`, the server closes the connection.

### Step 4: ready Payload

After `auth_ok`, the server sends a `ready` message containing all initial state.

### Step 5: Member Join + Presence

The server broadcasts to all connected clients:

```json
{ "type": "member_join", "payload": { "user": { "id": 1, "username": "alex", "avatar": "uuid.png", "role": "admin" } } }
{ "type": "presence", "payload": { "user_id": 1, "status": "online" } }
```

### Periodic Session Revalidation

Every 10 messages, the server re-checks the session token against the database. If the session has been revoked, expired, or the user banned, the connection is closed immediately.

---

## Heartbeat and Connection Liveness

### Client Ping

The client sends a JSON ping every 30 seconds:

```json
{ "type": "ping", "payload": {} }
```

### Server Pong

The server responds immediately:

```json
{ "type": "pong" }
```

### Server Stale Client Sweep

Every 30 seconds, the server checks all clients. Any client with no activity for 90 seconds is forcibly disconnected. Normal chat activity also keeps the connection alive.

---

## Reconnection with State Recovery

When a connection drops, the client automatically reconnects with exponential backoff (1s to 30s max) and sends `last_seq` in the `auth` message.

| Condition | Server Behavior |
|-----------|-----------------|
| `last_seq == 0` | Full flow: `auth_ok` + `ready` + `member_join` + `presence` |
| `last_seq > 0` AND seq in buffer | Replay flow: `auth_ok` + missed events + `presence` (no `member_join`, no `ready`) |
| `last_seq > 0` AND seq NOT in buffer | Full flow (fallback): same as `last_seq == 0` |

DM events are not stored in the ring buffer and are only recoverable via the full `ready` payload.

---

## Initial State (ready)

Sent once after `auth_ok` (fresh connection or replay fallback).

```json
{
  "type": "ready",
  "payload": {
    "channels": [ ... ],
    "dm_channels": [ ... ],
    "members": [ ... ],
    "voice_states": [ ... ],
    "roles": [ ... ],
    "server_name": "My Server",
    "motd": "Welcome!"
  }
}
```

### Payload Fields

**channels[]:** `id`, `name`, `type` (`text`/`voice`/`announcement`), `category`, `position`, `unread_count` (text only), `last_message_id` (text only)

**dm_channels[]:** `channel_id`, `recipient` (user object with `id`, `username`, `avatar`, `status`), `last_message_id`, `last_message`, `last_message_at`, `unread_count`

**members[]:** All registered users with `id`, `username`, `avatar`, `role` (lowercase name), `status`

**voice_states[]:** All users currently in any voice channel: `channel_id`, `user_id`, `muted`, `deafened`

**roles[]:** All server roles with `id`, `name`, `color`, `permissions` (bitfield)

---

## Chat Messages

### chat_send (Client -> Server)

```json
{
  "type": "chat_send",
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "payload": {
    "channel_id": 5,
    "content": "Hello everyone!",
    "reply_to": null,
    "attachments": ["upload-uuid-1"]
  }
}
```

| Field | Type | Required | Constraints |
|-------|------|----------|-------------|
| `channel_id` | number | Yes | Positive integer |
| `content` | string | Yes* | Max 4000 runes. HTML-sanitized. *Can be empty if `attachments` is non-empty. |
| `reply_to` | number or null | No | Message ID being replied to |
| `attachments` | string[] | No | Upload IDs from `POST /api/v1/uploads`. Requires `ATTACH_FILES` permission. |

### chat_send_ok (Server -> Client)

Direct response to sender (no seq):

```json
{
  "type": "chat_send_ok",
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "payload": {
    "message_id": 1042,
    "timestamp": "2026-03-14T10:30:00Z"
  }
}
```

### chat_message (Server -> Client, broadcast)

```json
{
  "seq": 42,
  "type": "chat_message",
  "payload": {
    "id": 1042,
    "channel_id": 5,
    "user": {
      "id": 1,
      "username": "alex",
      "avatar": "uuid.png",
      "role": "admin"
    },
    "content": "Hello everyone!",
    "reply_to": null,
    "timestamp": "2026-03-14T10:30:00Z",
    "attachments": [],
    "reactions": [],
    "pinned": false
  }
}
```

### chat_edit (Client -> Server)

```json
{
  "type": "chat_edit",
  "id": "req-uuid",
  "payload": {
    "message_id": 1042,
    "content": "Hello everyone! (edited)"
  }
}
```

Own messages only. Max 4000 runes.

### chat_edited (Server -> Client, broadcast)

```json
{
  "seq": 43,
  "type": "chat_edited",
  "payload": {
    "message_id": 1042,
    "channel_id": 5,
    "content": "Hello everyone! (edited)",
    "edited_at": "2026-03-14T10:31:00Z"
  }
}
```

### chat_delete (Client -> Server)

```json
{
  "type": "chat_delete",
  "id": "req-uuid",
  "payload": {
    "message_id": 1042
  }
}
```

Moderators with `MANAGE_MESSAGES` can delete others' messages (non-DM channels only).

### chat_deleted (Server -> Client, broadcast)

```json
{
  "seq": 44,
  "type": "chat_deleted",
  "payload": {
    "message_id": 1042,
    "channel_id": 5
  }
}
```

---

## Reactions

### reaction_add / reaction_remove (Client -> Server)

```json
{
  "type": "reaction_add",
  "payload": {
    "message_id": 1042,
    "emoji": "\ud83d\udc4d"
  }
}
```

Rate limited at 5/sec. Requires `ADD_REACTIONS` permission (or DM participant).

### reaction_update (Server -> Client, broadcast)

```json
{
  "seq": 45,
  "type": "reaction_update",
  "payload": {
    "message_id": 1042,
    "channel_id": 5,
    "emoji": "\ud83d\udc4d",
    "user_id": 1,
    "action": "add"
  }
}
```

`action` is `"add"` or `"remove"`.

---

## Typing Indicators

### typing_start (Client -> Server)

```json
{ "type": "typing_start", "payload": { "channel_id": 5 } }
```

Rate limited: 1 per 3 seconds per user per channel. Silently dropped when rate limited.

### typing (Server -> Client, broadcast)

```json
{
  "type": "typing",
  "payload": {
    "channel_id": 5,
    "user_id": 1,
    "username": "alex"
  }
}
```

Typing broadcasts are ephemeral -- they are NOT stored in the replay ring buffer.

---

## Presence

### presence_update (Client -> Server)

```json
{ "type": "presence_update", "payload": { "status": "online" } }
```

Valid values: `"online"`, `"idle"`, `"dnd"`, `"offline"`. Rate limited: 1 per 10 seconds.

### presence (Server -> Client, broadcast)

```json
{
  "seq": 50,
  "type": "presence",
  "payload": {
    "user_id": 1,
    "status": "online"
  }
}
```

---

## Channel Focus

### channel_focus (Client -> Server)

```json
{ "type": "channel_focus", "payload": { "channel_id": 5 } }
```

Tells the server which channel the user is currently viewing. Affects broadcast delivery and unread tracking.

---

## Channel Updates

All channel update messages are broadcast to all connected clients. Triggered by REST API calls from admins.

### channel_create (Server -> Client, broadcast)

```json
{
  "seq": 60,
  "type": "channel_create",
  "payload": {
    "id": 8,
    "name": "gaming",
    "type": "text",
    "category": "Hangout",
    "topic": "",
    "position": 3
  }
}
```

### channel_update (Server -> Client, broadcast)

Full channel object (all fields).

### channel_delete (Server -> Client, broadcast)

```json
{
  "seq": 62,
  "type": "channel_delete",
  "payload": { "id": 8 }
}
```

---

## Member Updates

All member messages are broadcast to all connected clients.

### member_join (Server -> Client, broadcast)

Sent when a user first connects (fresh connection, not reconnect replay).

```json
{
  "seq": 70,
  "type": "member_join",
  "payload": {
    "user": {
      "id": 5,
      "username": "newuser",
      "avatar": null,
      "role": "member"
    }
  }
}
```

### member_update (Server -> Client, broadcast)

Triggered when an admin changes a user's role.

```json
{
  "seq": 71,
  "type": "member_update",
  "payload": {
    "user_id": 5,
    "role": "moderator"
  }
}
```

### member_ban (Server -> Client, broadcast)

```json
{
  "seq": 72,
  "type": "member_ban",
  "payload": { "user_id": 5 }
}
```

---

## Voice Signaling

Voice uses LiveKit as the SFU. WebSocket messages handle signaling (join/leave/state) while the actual audio/video flows through LiveKit's own WebSocket connection.

### voice_join (Client -> Server)

```json
{ "type": "voice_join", "payload": { "channel_id": 10 } }
```

On success, server sends (in order):
1. `voice_token` -- LiveKit JWT + URL
2. `voice_state` broadcast -- joiner's state to all clients
3. Existing `voice_state` messages -- one per existing participant (to joiner only)
4. `voice_config` -- channel audio settings (to joiner only)

### voice_token (Server -> Client, direct)

```json
{
  "type": "voice_token",
  "payload": {
    "channel_id": 10,
    "token": "eyJhbGciOiJIUzI1NiIs...",
    "url": "/livekit",
    "direct_url": "ws://localhost:7880"
  }
}
```

### voice_config (Server -> Client, direct)

```json
{
  "type": "voice_config",
  "payload": {
    "channel_id": 10,
    "quality": "medium",
    "bitrate": 64000,
    "max_users": 50
  }
}
```

Quality presets:

| Preset | Bitrate |
|--------|---------|
| `low` | 32,000 bps |
| `medium` | 64,000 bps |
| `high` | 128,000 bps |

### voice_leave (Client -> Server)

```json
{ "type": "voice_leave", "payload": {} }
```

### voice_leave (Server -> Client, broadcast)

```json
{
  "seq": 80,
  "type": "voice_leave",
  "payload": {
    "channel_id": 10,
    "user_id": 1
  }
}
```

### voice_state (Server -> Client, broadcast)

```json
{
  "seq": 81,
  "type": "voice_state",
  "payload": {
    "channel_id": 10,
    "user_id": 1,
    "username": "alex",
    "muted": false,
    "deafened": false,
    "speaking": false,
    "camera": false,
    "screenshare": false
  }
}
```

### voice_mute / voice_deafen (Client -> Server)

```json
{ "type": "voice_mute", "payload": { "muted": true } }
{ "type": "voice_deafen", "payload": { "deafened": true } }
```

### voice_camera (Client -> Server)

```json
{ "type": "voice_camera", "payload": { "enabled": true } }
```

Rate limited: 2/sec. Requires `USE_VIDEO` permission.

### voice_screenshare (Client -> Server)

```json
{ "type": "voice_screenshare", "payload": { "enabled": true } }
```

Rate limited: 2/sec. Requires `SHARE_SCREEN` permission.

### voice_token_refresh (Client -> Server)

```json
{ "type": "voice_token_refresh", "payload": {} }
```

Rate limited: 1 per 60 seconds. Must be in a voice channel.

---

## Direct Messages

### dm_channel_open (Server -> Client)

Sent when a DM is opened, created, or auto-reopened by an incoming message.

```json
{
  "type": "dm_channel_open",
  "payload": {
    "channel_id": 100,
    "recipient": {
      "id": 2,
      "username": "jordan",
      "avatar": "uuid.png",
      "status": "online"
    }
  }
}
```

### dm_channel_close (Server -> Client)

```json
{
  "type": "dm_channel_close",
  "payload": { "channel_id": 100 }
}
```

### DM Authorization

All handlers that touch a channel check the channel type and branch to participant-based authorization for DMs instead of role-based permissions. This applies to: `chat_send`, `chat_edit`, `chat_delete`, `reaction_add`/`remove`, `typing_start`, `channel_focus`.

---

## Server Restart

### server_restart (Server -> Client, broadcast)

```json
{
  "seq": 100,
  "type": "server_restart",
  "payload": {
    "reason": "update",
    "delay_seconds": 5
  }
}
```

---

## Error Handling

### error (Server -> Client)

```json
{
  "type": "error",
  "id": "original-req-uuid",
  "payload": {
    "code": "FORBIDDEN",
    "message": "No permission to post here"
  }
}
```

### Error Codes

| Code | Description |
|------|-------------|
| `BAD_REQUEST` | Invalid payload format or field values |
| `INTERNAL` | Server-side error |
| `NOT_FOUND` | Channel or message not found |
| `FORBIDDEN` | Missing required permission |
| `RATE_LIMITED` | Too many requests (includes `retry_after` in seconds) |
| `ALREADY_JOINED` | Already in this voice channel |
| `CHANNEL_FULL` | Voice channel at capacity |
| `VOICE_ERROR` | Voice-specific error |
| `VIDEO_LIMIT` | Maximum video streams reached |
| `BANNED` | User is banned |
| `INVALID_JSON` | Message is not valid JSON |
| `UNKNOWN_TYPE` | Unrecognized message type |
| `SLOW_MODE` | Channel has slow mode enabled |
| `CONFLICT` | Duplicate reaction or constraint violation |

After 10 consecutive invalid JSON messages, the connection is forcibly closed.

---

## Rate Limits

All rate limits are enforced server-side using a token bucket rate limiter.

| Action | Limit | Window | Error Response |
|--------|-------|--------|----------------|
| Chat send | 10 | 1 second | `RATE_LIMITED` error |
| Chat edit | 10 | 1 second | `RATE_LIMITED` error |
| Chat delete | 10 | 1 second | `RATE_LIMITED` error |
| Typing | 1 | 3 seconds | Silently dropped |
| Presence | 1 | 10 seconds | `RATE_LIMITED` error |
| Reactions | 5 | 1 second | `RATE_LIMITED` error |
| Voice camera | 2 | 1 second | `RATE_LIMITED` error |
| Voice screenshare | 2 | 1 second | `RATE_LIMITED` error |
| Voice token refresh | 1 | 60 seconds | `RATE_LIMITED` error |

---

## Message Type Reference Table

### Client -> Server (18 types)

| Type | Rate Limit | Notes |
|------|-----------|-------|
| `auth` | N/A (first message) | Token + optional last_seq |
| `chat_send` | 10/sec | + slow mode per channel |
| `chat_edit` | 10/sec | Own messages only |
| `chat_delete` | 10/sec | Own or mod (non-DM) |
| `reaction_add` | 5/sec | |
| `reaction_remove` | 5/sec | |
| `typing_start` | 1/3sec/channel | Silently dropped |
| `channel_focus` | None | Updates read state |
| `presence_update` | 1/10sec | |
| `voice_join` | None | |
| `voice_leave` | None | Empty payload |
| `voice_mute` | None | |
| `voice_deafen` | None | |
| `voice_camera` | 2/sec | Requires USE_VIDEO |
| `voice_screenshare` | 2/sec | Requires SHARE_SCREEN |
| `voice_token_refresh` | 1/60sec | Must be in voice |
| `ping` | None | Heartbeat |

### Server -> Client (25+ types)

| Type | Has seq? | Delivery |
|------|----------|----------|
| `auth_ok` | No | Direct |
| `auth_error` | No | Direct (then close) |
| `ready` | No | Direct |
| `chat_message` | Non-DM only | Channel or DM participants |
| `chat_send_ok` | No | Direct to sender |
| `chat_edited` | Non-DM only | Channel or DM participants |
| `chat_deleted` | Non-DM only | Channel or DM participants |
| `reaction_update` | Non-DM only | Channel or DM participants |
| `typing` | No | Channel (excl. sender) or DM |
| `presence` | Yes | All clients |
| `channel_create` | Yes | All clients |
| `channel_update` | Yes | All clients |
| `channel_delete` | Yes | All clients |
| `voice_state` | Yes | All clients |
| `voice_leave` | Yes | All clients |
| `voice_config` | No | Direct to joiner |
| `voice_token` | No | Direct to joiner |
| `member_join` | Yes | All clients |
| `member_update` | Yes | All clients |
| `member_ban` | Yes | All clients |
| `dm_channel_open` | No | Direct to participant |
| `dm_channel_close` | No | Direct to participant |
| `server_restart` | Yes | All clients |
| `error` | No | Direct to requester |
| `pong` | No | Direct to pinger |