Device Obtaining Device Shadow Data from the Platform

Function

This API is used by a device to obtain device shadow data from IoTDA. You can configure desired data in a device shadow through an application or the platform. When a device goes online and subscribes to this topic, the device can obtain the device shadow data from the platform and synchronize the desired device properties.

The interaction logic is described as follows:

1. The application calls the API for configuring desired properties in a device shadow or configures the device shadow data on the console.

2. The device (which has subscribed to the corresponding topic) proactively sends a request to obtain the device shadow data from the platform.

3. The platform responds to the device request and returns the device shadow data.

4. The device parses the desired properties and modifies device properties.

Topic

Upstream: $oc/devices/{device_id}/sys/shadow/get/request_id={request_id}

Downstream: $oc/devices/{device_id}/sys/shadow/get/response/request_id={request_id}

• {request_id} is used to uniquely identify a request. If this parameter is carried in a message sent by a device, ensure that the parameter value is unique on the device by using an incremental number or UUID.
• The upstream request parameters on the device side carry the unique ID, which is carried in request_id in the downstream topic to identify the unique request chain.
• When subscribing to a downstream topic, you are advised to use the wildcard character # to replace request_id={request_id}, that is, $oc/devices/{device_id}/sys/shadow/get/response/#.

Upstream Request Parameters

Downstream Response Parameters

ShadowData structure

PropertiesData structure

Example Upstream Request

Topic: $oc/devices/{device_id}/sys/shadow/get/request_id={request_id} 
Data format:
{
	"object_device_id": "40fe3542-f4cc-4b6a-98c3-61a49ba1acd4",
	"service_id": "WaterMeter"
}

Example Downstream Response

Topic: $oc/devices/{device_id}/sys/shadow/get/response/request_id={request_id}
Data format:
{
  "object_device_id": "40fe3542-f4cc-4b6a-98c3-61a49ba1acd4",
  "shadow": [
    {
      "service_id": "WaterMeter",
      "desired": {
        "properties": {
          "temperature": "60"
        },
        "event_time": "20151212T121212Z"
      },
      "reported": {
        "properties": {
          "temperature": "60"
        },
        "event_time": "20151212T121212Z"
      },
      "version": 1
    }
  ]
}