Device Reporting Messages

Introduction

Message reporting is a method by which a device directly sends data to the cloud and forwards the data to applications or other Huawei Cloud services through data forwarding. The platform does not parse or store the messages reported by devices. In this case, a product model is not required.

Figure 1 Process of device message reporting

Scenarios

IoTDA does not parse or store the data reported by devices. Instead, it forwards the data (see Data Forwarding Process) to other Huawei Cloud services for storage and processing.

Constraints

• Maximum size of a single message: 1 MB.
• Maximum bandwidth of a single MQTT connection: 1 Mbit/s.
• Maximum upstream messages for a single MQTT connection per second: 50 (one request is considered as one message).

Process

Figure 2 Process of device message reporting

1. Create a product and device by referring to Product Creation and Registering an Individual Device.
2. Device authentication: The platform checks whether the device has the access permission.
3. Device message reporting: Devices report messages through protocols such as MQTT and HTTPS.

   Use different APIs for different protocols.

   MQTT: Use the message reporting API (see MQTT Device Reporting a Message) to report data to the platform.

   • Example topic of MQTT message reporting:

     $oc/devices/{device_id}/sys/messages/up    

   • Example format of MQTT message reporting:

     {
         "content": {"hello":"123"} 
     }

   HTTPS: Use the message reporting API (see HTTP Message Reporting) to report data to the platform. For details about how to obtain the access token, see HTTP Device Connection Authentication. The following is an example of HTTPS device message reporting.

   POST https://{endpoint}/v5/devices/{device_id}/sys/messages/up 
   Content-Type: application/json
   access_token: ********
   {
       "name": "name",
       "id": "id",
       "content": "messageUp"
   }

   

   For details about the APIs, see MQTT Device Reporting a Message and HTTP Message Reporting.

4. Data forwarding: With the data forwarding function (see Data Forwarding Process), data can be forwarded to applications or other Huawei Cloud services for further processing.

Message Reporting Using Java SDK

This section describes how to use Java SDKs for the development of message reporting. JDK 1.8 or later is used.

Configure the SDK on the device side:

1. Obtain the SDK code by referring to SDK Download.
2. Configure the Maven dependency of the SDK on devices.

   <dependency>
   	<groupId>com.huaweicloud</groupId>
   	<artifactId>iot-device-sdk-java</artifactId>
   	<version>1.1.4</version>
   </dependency>

3. Configure the SDK and device connection parameters on devices.

   // Load the CA certificate of the platform. For details, see Certificates.
   URL resource = BroadcastMessageSample.class.getClassLoader().getResource("ca.jks");
   File file = new File(resource.getPath());
   
   // The format is ssl://Access address:Port number.
   // To obtain the access address, log in to the IoTDA console. In the navigation pane, choose Overview and check the access information in the Instance Information area. Select the access address corresponding to port 8883.
   String serverUrl = "ssl://<localhost>:8883";
   // Device ID created on the platform
   String deviceId = "<deviceId>";
   // Secret corresponding to the device ID
   String deviceSecret = "<deviceSecret>";
   // Create a device.
   IoTDevice device = new IoTDevice(serverUrl, deviceId, deviceSecret, file);
   if (device.init() != 0) {
       return;
   }

4. Report a device message.

   device.getClient().reportDeviceMessage(new DeviceMessage("hello"), new ActionListener() {
       @Override        
       public void onSuccess(Object context) {             
           log.info("reportDeviceMessage success: ");
       }          
       @Override        
       public void onFailure(Object context, Throwable var2) {
           log.error("reportDeviceMessage fail: "+var2);         
       }     
   });

Verification

1. On the IoTDA console, choose Devices > All Devices, select a device to access its details page, and click Start Trace on the Message Trace tab page.
   Figure 3 Message tracing - Starting message tracing
   

2. Run the SDK code on the device. The following is an example of the log format when the device reports a message.
   Figure 4 Java SDK message reporting result log
   

3. Check the result on the Message Trace tab page, which indicates that the platform has received the message from the device and the forwarding rule has been triggered.
   Figure 5 Message tracing - Message reporting triggering a forwarding rule