mini-prog/doc/gateway-protocol-spec.md

实时网关协议草案

本文档描述 realtime-gateway 第一版协议草案，范围只覆盖 MVP。

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1. 连接方式

• 协议：WebSocket
• 地址：/ws
• 编码：JSON
• 通信模式：客户端主动发消息，服务端返回状态或事件

---

2. 消息类型

客户端上行 type：

• authenticate
• join_channel
• subscribe
• publish
• snapshot

服务端下行 type：

• welcome
• authenticated
• subscribed
• published
• snapshot
• event
• error

---

3. 鉴权

3.1 authenticate

{
  "type": "authenticate",
  "role": "producer",
  "token": "dev-producer-token"
}

说明：

• role 可选值：producer、consumer、controller
• 第一版 consumer 可允许匿名，是否启用由配置控制

3.2 join_channel

{
  "type": "join_channel",
  "role": "producer",
  "channelId": "ch-xxxx",
  "token": "producer-token"
}

说明：

• channelId 必填
• token 必须和 channelId 对应
• role 不同，使用的 token 也不同
  • producerToken
  • consumerToken
  • controllerToken

---

4. 订阅

4.1 subscribe

{
  "type": "subscribe",
  "subscriptions": [
    {
      "deviceId": "child-001",
      "topic": "telemetry.location"
    }
  ]
}

支持字段：

• channelId
• deviceId
• groupId
• topic

第一版匹配规则：

• 非空字段必须全部匹配
• 空字段视为不过滤

---

5. 发布

5.1 publish

{
  "type": "publish",
  "envelope": {
    "schemaVersion": 1,
    "messageId": "msg-001",
    "timestamp": 1711267200000,
    "topic": "telemetry.location",
    "source": {
      "kind": "producer",
      "id": "watch-001",
      "mode": "real"
    },
    "target": {
      "channelId": "ch-xxxx",
      "deviceId": "child-001",
      "groupId": "class-a"
    },
    "payload": {
      "lat": 31.2304,
      "lng": 121.4737,
      "speed": 1.2,
      "bearing": 90,
      "accuracy": 6,
      "coordSystem": "GCJ02"
    }
  }
}

说明：

• 只有 producer 和 controller 能发布
• 第一版不做复杂 schema 校验
• 第一版缓存键为 channelId + deviceId
• 如果连接已经通过 join_channel 加入通道，服务端会自动补全 target.channelId

---

6. 快照

6.1 snapshot

{
  "type": "snapshot",
  "subscriptions": [
    {
      "channelId": "ch-xxxx",
      "deviceId": "child-001"
    }
  ]
}

服务端返回：

{
  "type": "snapshot",
  "sessionId": "sess-2",
  "state": {
    "schemaVersion": 1,
    "timestamp": 1711267200000,
    "topic": "telemetry.location",
    "source": {
      "kind": "producer",
      "id": "watch-001",
      "mode": "real"
    },
    "target": {
      "deviceId": "child-001"
    },
    "payload": {
      "lat": 31.2304,
      "lng": 121.4737
    }
  }
}

---

7. 服务端消息

7.1 welcome

{
  "type": "welcome",
  "sessionId": "sess-1"
}

7.2 authenticated

{
  "type": "authenticated",
  "sessionId": "sess-1"
}

7.3 subscribed

{
  "type": "subscribed",
  "sessionId": "sess-1"
}

7.4 joined_channel

{
  "type": "joined_channel",
  "sessionId": "sess-1",
  "state": {
    "channelId": "ch-xxxx",
    "deliveryMode": "cache_latest"
  }
}

7.5 published

{
  "type": "published",
  "sessionId": "sess-1"
}

7.6 event

{
  "type": "event",
  "envelope": {
    "schemaVersion": 1,
    "timestamp": 1711267200000,
    "topic": "telemetry.location",
    "source": {
      "kind": "producer",
      "id": "watch-001",
      "mode": "real"
    },
    "target": {
      "channelId": "ch-xxxx",
      "deviceId": "child-001"
    },
    "payload": {
      "lat": 31.2304,
      "lng": 121.4737
    }
  }
}

7.7 error

{
  "type": "error",
  "error": "authentication failed"
}

---

8. 第一版约束

• 不做历史回放协议
• 不做压缩和二进制编码
• 不做批量发布
• 不做通配符 topic
• 不做持久会话
• 不做 ACK 队列

---

9. 管理接口

9.1 创建 channel

POST /api/channel/create

请求：

{
  "label": "debug-a",
  "deliveryMode": "cache_latest",
  "ttlSeconds": 28800
}

返回：

{
  "snapshot": {
    "id": "ch-xxxx",
    "label": "debug-a",
    "deliveryMode": "cache_latest"
  },
  "producerToken": "....",
  "consumerToken": "....",
  "controllerToken": "...."
}

9.2 管理台读取接口

• GET /api/admin/overview
• GET /api/admin/sessions
• GET /api/admin/latest
• GET /api/admin/channels
• GET /api/admin/traffic
• GET /api/admin/live

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10. 第二阶段预留

后续协议可以增加：

• command
• batch_publish
• rule_event
• plugin_status
• replay_control
• auth_refresh