DJI Pilot 2 Publishes Topology Update for Online Devices

After loading the cloud module, DJI Pilot 2 immediately initiates an MQTT connection request to the server. After the connection request is successful, a status topic is sent to the server immediately afterwards.

Communication method: MQTT

API interface:

Scenes	Published topic	Subscribed topic	remark
Device online	sys/product/#{pid}/status	sys/product/#{pid}/status_reply

Parameter Description:

• #{pid}: Refers to the product ID of the gateway device. It is generally represented by the SN number of the device. Each device is different, so it is necessary to use wildcards when the server subscribes to Topic.

Parameter	Required	Type	Illustration
tid	Yes	string
bid	Yes	string
method	Yes	string	Only supports update_topo
timestamp	Yes	int	13-bit time stamp
data	Yes	object	Online data
data > type	Yes	int	Product type of gateway equipment
data > sub_type	Yes	int	Product sub-type of gateway sub-device
data > device_secret	Yes	string	The device secret of the gateway device
data > nonce	Yes	string	The device secret of the gateway device
data > version	Yes	int	The thing model version of the gateway device
data > sub_devices	Yes	array	List of sub-devices, an empty array means there are no sub-devices
data > sub_devices > sn	Yes	string	The serial number of the child device
data > sub_devices > type	Yes	int	Product type of sub-device
data > sub_devices > sub_type	Yes	int	Product sub-type of sub-device
data > sub_devices > index	Yes	int	The channel index of the connected gateway device. For example: A, B
data > sub_devices > device_secret	Yes	string	The device secret of the child device
data > sub_devices > nonce	Yes	string	The device secret of the child device
data > sub_devices > version	no	int	Sub-device's thing model version

Example:

// Topic: sys/product/#{pid}/status
// Gateway devices and sub devices are online.
{
    "tid": "tid001",
    "bid": "bid001",
    "method": "update_topo",
    "timestamp": 1234567890123,
    "data": {
        "type": 98,
        "sub_type": 0,
        "device_secret":"secret",
        "nonce":"nonce",
        "version": 1,
        "sub_devices":[{
            "sn": "drone001",
            "type": 116,
            "sub_type": 0,
            "index": "A",
            "device_secret":"secret",
            "nonce":"nonce", 
            "version": 1
        }]
    }
}

// Topic: sys/product/#{pid}/status
// Sub devices are offline.
{
    "tid": "tid001",
    "bid": "bid001",
    "method": "update_topo",
    "timestamp": 1234567890123,
    "data": {
        "type": 98,
        "sub_type": 0,
        "device_secret":"secret",
        "nonce":"nonce",
        "version": 1,
        "sub_devices":[]
    }
}

// Topic: sys/product/#{pid}/status_reply 
{
    "tid": "xxx",
    "bid": "xxx",
    "method": "update_topo",
    "timestamp": 1234567890123,
    "data": {
        "result": 0
    }
}

Notice:

1. As long as there is a device topology change, the DJI Pilot 2 side will send a topic to the server side to update the topology.

2. When the server side receives the status topic, it needs to send the status_reply topic to reply, otherwise the DJI Pilot 2 side will keep on pushing until it stops after receiving the reply.