C#

本文主要介绍如何在 C# 项目中使用 paho.mqtt.m2mqtt 客户端库，实现客户端与 SX-IOT物联网设备的连接、订阅、收发消息等功能。 C# 是微软推出的一种基于 .NET框架的、面向对象的高级编程语言。 C#是一种由C和C++派生出来的面向对象的编程语言。它在继承C和C++强大功能的同时去掉了一些它们的复杂特性，使其成为C语言家族中的一种高效强大的编程语言。

前提条件

安装依赖包

sudo apt remove 'dotnet*' 'aspnet*' 'netstandard*'
sudo rm /etc/apt/sources.list.d/microsoft-prod.list
sudo apt update
sudo apt install dotnet-sdk-6.0
dotnet --version
dotnet new console -o mqtt-client-Csharp-paho
cd mqtt-client-Csharp-paho
dotnet add package M2Mqtt --version 4.3.0

连接使用

连接设置

本文将使用自定义的接入认证方式，服务器接入信息如下： -Broker: mqtt.geek-smart.cn -TCP Port: 1883 -WebSocket Port: 8083

导入依赖包

 using System;
 using uPLibrary.Networking.M2Mqtt;
 using uPLibrary.Networking.M2Mqtt.Messages;

定义连接地址、认证信息以及消息发布主题

设置 MQTT Broker 连接地址，端口以及 topic。

 string broker = "mqtt.geek-smart.cn";
 int port = 1883;
 string pub_topic = "/HYUGHV/lVtAcHuor***/4cebd60bf***/publish";
 string sub_topic = "/HYUGHV/lVtAcHuor***/4cebd60bf***/subscribe";
 string clientId = "csharp-client";
 string username = "************";
 string password = "************";

定义消息发布函数

 static void Publish(MqttClient client, string topic)
 {
     int msg_count = 0;
     while (true)
     {
         System.Threading.Thread.Sleep(1*1000);
         string msg = "{'type':'info'}";
         client.Publish(topic, System.Text.Encoding.UTF8.GetBytes(msg));
         Console.WriteLine("Send `{0}` to topic `{1}`", msg, topic);
         msg_count++;
     }
 }

定义 subscribe 回调函数，用于打印订阅主题接收的消息内容

static void Subscribe(MqttClient client, string topic)
 {
     client.MqttMsgPublishReceived += client_MqttMsgPublishReceived;
     client.Subscribe(new string[] { topic }, new byte[] { MqttMsgBase.QOS_LEVEL_AT_MOST_ONCE });
 }
 static void client_MqttMsgPublishReceived(object sender,MqttMsgPublishEventArgs e)
 {
     string payload = System.Text.Encoding.Default.GetString(e.Message);
     Console.WriteLine("Received `{0}` from `{1}` topic", payload, e.Topic.ToString());
 }

初始化 MQTT 客户端并订阅主题

 static MqttClient ConnectMQTT(string broker, int port, stringclientId, string username, string password)
 {
     MqttClient client = new MqttClient(broker, port, false, MqttSslProtocols.None, null, null);
     client.Connect(clientId, username, password);
     if (client.IsConnected)
     {
         Console.WriteLine("Connected to MQTT Broker");
     }
     else
     {
         Console.WriteLine("Failed to connect");
     }
     return client;
 }

完整代码

<Project Sdk="Microsoft.NET.Sdk">
 
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0</TargetFramework>
    <RootNamespace>mqtt_client_Csharp_paho</RootNamespace>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
 
  <ItemGroup>
    <PackageReference Include="M2Mqtt" Version="4.3.0" />
  </ItemGroup>
 
</Project>

 using System;
 using uPLibrary.Networking.M2Mqtt;
 using uPLibrary.Networking.M2Mqtt.Messages;
 
 namespace csharpMQTT
 {
     class Program
     {
         static MqttClient ConnectMQTT(string broker, int port, string clientId, string username, string password)
         {
             MqttClient client = new MqttClient(broker, port, false, MqttSslProtocols.None, null, null);
             client.Connect(clientId, username, password);
             if (client.IsConnected)
             {
                 Console.WriteLine("Connected to MQTT Broker");
             }
             else
             {
                 Console.WriteLine("Failed to connect");
             }
             return client;
         }
 
         static void Publish(MqttClient client, string topic)
         {
             int msg_count = 0;
             while (true)
             {
                 System.Threading.Thread.Sleep(1*1000);
                 string msg = "{'type':'info'}";
                 client.Publish(topic, System.Text.Encoding.UTF8.GetBytes(msg));
                 Console.WriteLine("Send `{0}` to topic `{1}`", msg, topic);
                 msg_count++;
             }
         }
 
         static void Subscribe(MqttClient client, string topic)
         {
             client.MqttMsgPublishReceived += client_MqttMsgPublishReceived;
             client.Subscribe(new string[] { topic }, new byte[] { MqttMsgBase.QOS_LEVEL_AT_MOST_ONCE });
         }
         static void client_MqttMsgPublishReceived(object sender, MqttMsgPublishEventArgs e)
         {
             string payload = System.Text.Encoding.Default.GetString(e.Message);
             Console.WriteLine("Received `{0}` from `{1}` topic", payload, e.Topic.ToString());
         }
 
         static void Main(string[] args)
         {
             string broker = "mqtt.geek-smart.cn";
             int port = 1883;
             string pub_topic = "/HYUGHV/lVtAcHuor***/4cebd60bf***/publish";
             string sub_topic = "/HYUGHV/lVtAcHuor***/4cebd60bf***/subscribe";
             string clientId = "csharp-client";
             string username = "************";
             string password = "************";
             MqttClient client = ConnectMQTT(broker, port, clientId, username, password);
             Subscribe(client, sub_topic);
             Publish(client, pub_topic);
         }
     }
 }

测试验证

运行

dotnet run

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