概述

MQTT协议是基于PUB/SUB的异步通信模式，不适用于服务端同步控制设备端返回结果的场景。前面博客基于开源Java MQTT Client的阿里云物联网平台RRPC功能测试介绍了RRPC原理，使用Open API实现服务端的调用实现。本文介绍如何使用NET SDK在本地实现RRPC的服务端调用。

Step By Step

1、创建产品与设备

参考链接 准备工作部分。

2、设备端Code

import com.alibaba.taro.AliyunIoTSignUtil;
import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
import java.util.HashMap;
import java.util.Map;

public class IoTRRPCForSysTopicDemo {

    // 设备三元组信息
    public static String productKey = "a16MX******";
    public static String deviceName = "RRPC******";
    public static String deviceSecret = "Ayq069ifWO7WOmwKyswNLv6E********";
    public static String regionId = "cn-shanghai";

    // RRPC 系统Topic
    private static String subTopic = "/sys/" + productKey + "/" + deviceName+ "/rrpc/request/+";
    private static MqttClient mqttClient;

    public static void main(String [] args) {

        initAliyunIoTClient();

        // RRPC订阅Topic
        try {
            mqttClient.subscribe(subTopic);
        } catch (MqttException e) {
            e.printStackTrace();
        }

        mqttClient.setCallback(new MqttCallback() {
            @Override
            public void connectionLost(Throwable cause) {
                System.out.println("connectionLost:" + cause.getMessage());
            }

            @Override
            public void messageArrived(String topic, MqttMessage message) throws Exception {
                System.out.println("message: " + new String(message.getPayload()));
                System.out.println("topic:" + topic);

                // 根据RRPC请求消息Topic，构建RRPC响应消息Topic
                String responseTopic = topic.replace("request","response");
                MqttMessage message1 = new MqttMessage("resonse demo".getBytes("utf-8"));
                mqttClient.publish(responseTopic, message1);
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken token) {
            }
        });
    }

    /***
     * 初始化Client
     */
    private static void initAliyunIoTClient() {

        try {
            String clientId = "java" + System.currentTimeMillis();

            Map<String, String> params = new HashMap<>(16);
            params.put("productKey", productKey);
            params.put("deviceName", deviceName);
            params.put("clientId", clientId);
            String timestamp = String.valueOf(System.currentTimeMillis());
            params.put("timestamp", timestamp);

            // cn-shanghai
            String targetServer = "tcp://" + productKey + ".iot-as-mqtt." + regionId + ".aliyuncs.com:1883";

            String mqttclientId = clientId + "|securemode=3,signmethod=hmacsha1,timestamp=" + timestamp + "|";
            String mqttUsername = deviceName + "&" + productKey;
            String mqttPassword = AliyunIoTSignUtil.sign(params, deviceSecret, "hmacsha1");

            connectMqtt(targetServer, mqttclientId, mqttUsername, mqttPassword);

        } catch (Exception e) {
            System.out.println("initAliyunIoTClient error " + e.getMessage());
        }
    }

    public static void connectMqtt(String url, String clientId, String mqttUsername, String mqttPassword) throws Exception {

        MemoryPersistence persistence = new MemoryPersistence();
        mqttClient = new MqttClient(url, clientId, persistence);
        MqttConnectOptions connOpts = new MqttConnectOptions();
        // MQTT 3.1.1
        connOpts.setMqttVersion(4);
        connOpts.setAutomaticReconnect(false);
        connOpts.setCleanSession(true);

        connOpts.setUserName(mqttUsername);
        connOpts.setPassword(mqttPassword.toCharArray());
        connOpts.setKeepAliveInterval(60);

        mqttClient.connect(connOpts);
    }
}

3、云端Code

• 3.1 SDK安装:

Install-Package aliyun-net-sdk-iot -Version 7.4.0

• 3.2 NET Code

using System;
using System.Text;
using Aliyun.Acs.Core;
using Aliyun.Acs.Core.Exceptions;
using Aliyun.Acs.Core.Profile;
using Aliyun.Acs.Iot.Model.V20180120;

namespace IoTRRPCDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            // ak,sk https://yq.aliyun.com/articles/693979
            IClientProfile profile = DefaultProfile.GetProfile("cn-shanghai", "LTAIOZZg********", "v7CjUJCMk7j9aKduMAQLjy********");
            DefaultAcsClient client = new DefaultAcsClient(profile);
            client.SetConnectTimeoutInMilliSeconds(8000);// 设置 Client 连接超时时间，默认是5S，RRPC响应超过5S是必须设置


            var request = new RRpcRequest();
            request.Timeout = 8000;
            // 设置设备三元组信息
            request.DeviceName = "RRPC******";
            request.RequestBase64Byte = "5raI5oGv5LiL6KGM5rWL6K+V";  // 消息下行测试 base64编码内容
            request.ProductKey = "a16MX******";

            try
            {
                var response = client.GetAcsResponse(request);
                Console.WriteLine(Encoding.Default.GetString(response.HttpResponse.Content));
                Console.ReadKey();
            }
            catch (ServerException e)
            {
                Console.WriteLine("ServerException:");
                Console.WriteLine(e);
                Console.ReadKey();
            }
            catch (ClientException e)
            {
                Console.WriteLine("ClientException: ");
                Console.WriteLine(e);
                Console.ReadKey();
            }
        }
    }
}

4、测试情况

• 4.1 设备端

• 4.2 云端

参考链接

基于开源Java MQTT Client的阿里云物联网平台RRPC功能测试