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

1sudo apt remove 'dotnet*' 'aspnet*' 'netstandard*'
2sudo rm /etc/apt/sources.list.d/microsoft-prod.list
3sudo apt update
4sudo apt install dotnet-sdk-6.0
5dotnet --version
6dotnet new console -o mqtt-client-Csharp-paho
7cd mqtt-client-Csharp-paho
8dotnet 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

1 using System;
2 using uPLibrary.Networking.M2Mqtt;
3 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。

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

定义消息发布函数

 1 static void Publish(MqttClient client, string topic)
 2 {
 3     int msg_count = 0;
 4     while (true)
 5     {
 6         System.Threading.Thread.Sleep(1*1000);
 7         string msg = "{'type':'info'}";
 8         client.Publish(topic, System.Text.Encoding.UTF8.GetBytes(msg));
 9         Console.WriteLine("Send `{0}` to topic `{1}`", msg, topic);
10         msg_count++;
11     }
12 }

定义 subscribe 回调函数，用于打印订阅主题接收的消息内容

 1 static void Subscribe(MqttClient client, string topic)
 2 {
 3     client.MqttMsgPublishReceived += client_MqttMsgPublishReceived;
 4     client.Subscribe(new string[] { topic }, new byte[] { MqttMsgBase.QOS_LEVEL_AT_MOST_ONCE });
 5 }
 6 static void client_MqttMsgPublishReceived(object sender,MqttMsgPublishEventArgs e)
 7 {
 8     string payload = System.Text.Encoding.Default.GetString(e.Message);
 9     Console.WriteLine("Received `{0}` from `{1}` topic", payload, e.Topic.ToString());
10 }

初始化 MQTT 客户端并订阅主题

 1 static MqttClient ConnectMQTT(string broker, int port, stringclientId, string username, string password)
 2 {
 3     MqttClient client = new MqttClient(broker, port, false, MqttSslProtocols.None, null, null);
 4     client.Connect(clientId, username, password);
 5     if (client.IsConnected)
 6     {
 7         Console.WriteLine("Connected to MQTT Broker");
 8     }
 9     else
10     {
11         Console.WriteLine("Failed to connect");
12     }
13     return client;
14 }

完整代码

 1<Project Sdk="Microsoft.NET.Sdk">
 2
 3  <PropertyGroup>
 4    <OutputType>Exe</OutputType>
 5    <TargetFramework>net6.0</TargetFramework>
 6    <RootNamespace>mqtt_client_Csharp_paho</RootNamespace>
 7    <ImplicitUsings>enable</ImplicitUsings>
 8    <Nullable>enable</Nullable>
 9  </PropertyGroup>
10
11  <ItemGroup>
12    <PackageReference Include="M2Mqtt" Version="4.3.0" />
13  </ItemGroup>
14
15</Project>

 1 using System;
 2 using uPLibrary.Networking.M2Mqtt;
 3 using uPLibrary.Networking.M2Mqtt.Messages;
 4
 5 namespace csharpMQTT
 6 {
 7     class Program
 8     {
 9         static MqttClient ConnectMQTT(string broker, int port, string clientId, string username, string password)
10         {
11             MqttClient client = new MqttClient(broker, port, false, MqttSslProtocols.None, null, null);
12             client.Connect(clientId, username, password);
13             if (client.IsConnected)
14             {
15                 Console.WriteLine("Connected to MQTT Broker");
16             }
17             else
18             {
19                 Console.WriteLine("Failed to connect");
20             }
21             return client;
22         }
23
24         static void Publish(MqttClient client, string topic)
25         {
26             int msg_count = 0;
27             while (true)
28             {
29                 System.Threading.Thread.Sleep(1*1000);
30                 string msg = "{'type':'info'}";
31                 client.Publish(topic, System.Text.Encoding.UTF8.GetBytes(msg));
32                 Console.WriteLine("Send `{0}` to topic `{1}`", msg, topic);
33                 msg_count++;
34             }
35         }
36
37         static void Subscribe(MqttClient client, string topic)
38         {
39             client.MqttMsgPublishReceived += client_MqttMsgPublishReceived;
40             client.Subscribe(new string[] { topic }, new byte[] { MqttMsgBase.QOS_LEVEL_AT_MOST_ONCE });
41         }
42         static void client_MqttMsgPublishReceived(object sender, MqttMsgPublishEventArgs e)
43         {
44             string payload = System.Text.Encoding.Default.GetString(e.Message);
45             Console.WriteLine("Received `{0}` from `{1}` topic", payload, e.Topic.ToString());
46         }
47
48         static void Main(string[] args)
49         {
50             string broker = "mqtt.geek-smart.cn";
51             int port = 1883;
52             string pub_topic = "/HYUGHV/lVtAcHuor***/4cebd60bf***/publish";
53             string sub_topic = "/HYUGHV/lVtAcHuor***/4cebd60bf***/subscribe";
54             string clientId = "csharp-client";
55             string username = "************";
56             string password = "************";
57             MqttClient client = ConnectMQTT(broker, port, clientId, username, password);
58             Subscribe(client, sub_topic);
59             Publish(client, pub_topic);
60         }
61     }
62 }

测试验证

运行

1dotnet run