MQTT Reference

The current MQTT implementation is located at:

src/network/mqtt
src/service/network/impl/MqttLifecycleServiceImpl.cc

The HTML reference packaged at runtime is located at:

data/Interface/mqtt_v1.0.html

Topics

Direction	Topic	Description
Device -> Platform	/d2p/aibox	Registration messages and normal responses.
Device -> Platform	/d2p/aibox/heartbeat	Heartbeat messages.
Platform -> Device	/p2d/aibox/{deviceSn}	Platform downstream business requests.
Platform -> Device	/p2d/aibox/heartbeat/{deviceSn}	Platform heartbeat-related downstream messages.

After connecting, the device first subscribes to the two platform-to-device topics, then sends a registration message to /d2p/aibox. After successful registration, it sends a heartbeat to /d2p/aibox/heartbeat every 30 seconds.

Connection Parameters

System configuration fields are described in API Fields.

The current implementation supports two authentication modes:

authMode	Behavior
0	Built-in IoT authentication. clientId uses the device SN, username is aibox::{deviceSn}, and authKey is cwai.
Non-0	Normal username/password authentication. Uses clientId, userName, and passwd from the configuration.

deviceType in the connection parameters is fixed to box.

Message Envelope

An MQTT envelope consists of head and body:

{
  "head": {
    "requestId": "uuid",
    "action": "/gtw/cwai/System/QueryDeviceInfo",
    "deviceSn": "DEVICE_SN",
    "msgType": "request"
  },
  "body": "{\"example\":\"business json string\"}"
}

Field	Type	Description
head.requestId	string	Request ID. The response reuses this value.
head.action	string	Business interface path, for example /gtw/cwai/System/QueryDeviceInfo.
head.deviceSn	string	Device SN. The device rejects messages whose SN does not match.
head.msgType	string	register, heartbeat, request, or response.
body	string	JSON string. For downstream requests, the business JSON must be JSON.stringify-d and placed in this field.

Registration Message

The device sends to /d2p/aibox:

{
  "head": {
    "requestId": "uuid",
    "action": "",
    "deviceSn": "DEVICE_SN",
    "msgType": "register"
  },
  "body": {
    "devId": "DEVICE_SN",
    "supplier": "CWAI",
    "aiHostVersion": "v1.0.0",
    "engineType": "cpu",
    "deviceModel": "model",
    "devType": 2
  }
}

Field	Type	Description
body.devId	string	Device ID; currently the device SN.
body.supplier	string	Supplier; defaults to CWAI.
body.aiHostVersion	string	AI Host version.
body.engineType	string	Engine type.
body.deviceModel	string	Device model.
body.devType	number	Device type; the box currently uses 2.

Heartbeat Message

The device sends to /d2p/aibox/heartbeat:

{
  "head": {
    "requestId": "uuid",
    "action": "",
    "deviceSn": "DEVICE_SN",
    "msgType": "heartbeat"
  },
  "body": {
    "devId": "DEVICE_SN",
    "hostStatus": 0,
    "customScore": 1,
    "cpuUsage": 12.3,
    "memTotal": 8192,
    "memAvailable": 4096,
    "gpuUsage": 0,
    "gpuMemTotal": 0,
    "gpuMemAvailable": 0,
    "diskTotal": 128000,
    "diskAvailable": 64000
  }
}

The heartbeat publish ACK timeout is 2000 ms. Repeated failures beyond a threshold trigger a reconnect.

Platform Downstream Requests

The platform sends to /p2d/aibox/{deviceSn}:

{
  "head": {
    "requestId": "REQ-001",
    "action": "/gtw/cwai/System/QueryDeviceInfo",
    "deviceSn": "DEVICE_SN",
    "msgType": "request"
  },
  "body": "{}"
}

After receiving it, the device:

1. Validates that deviceSn equals the local SN.
2. Validates that msgType is request.
3. Uses head.action as the API route.
4. Dispatches the body string as business JSON to the ApiRouter.
5. Returns the response via /d2p/aibox.

Device Response

Device response envelope:

{
  "head": {
    "requestId": "REQ-001",
    "action": "/gtw/cwai/System/QueryDeviceInfo",
    "deviceSn": "DEVICE_SN",
    "msgType": "response"
  },
  "body": "{\"resCode\":1,\"resMsg\":[],\"resData\":{}}"
}

body is the business response JSON string; its field structure is consistent with the HTTP API response.