C# 完美实现物联网 MQTT 数据通信 - ToB企服应用市场:ToB评测及商务社交产业平台

[/code]注：在添加这两个包时，会自动添加其它依赖包
[*]在 Program.cs 编写 MQTT 通信（重点看[b]注释[/b]）
[code]using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Packets;
using MQTTnet.Protocol;
using System.Security.Authentication;
using MQTTnet.Formatter;
using MQTTnet.Extensions.WebSocket4Net;
using System.Threading;
namespace MQTTSample
{
internal class Program
{
static async Task Main(string[] args)
{
// 设计两个参数，是为了可以打开两个 CMD 客户端进行测试
if (args[0] == "publish")
{
Console.WriteLine("Publish message...");
await PublishMessage();
}
else
{
Console.WriteLine("Receive message...");
await SubscribeTopic();
}
}
// 循环不断地发布消息
private static async Task PublishMessage()
{
var i = 0;
while (i <= 1000)
{
var mqttFactory = new MqttFactory();
using (var mqttClient = mqttFactory.CreateMqttClient())
{
// 1. 连接 MQTT 服务器
var mqttClientOptions = new MqttClientOptionsBuilder()
.WithTcpServer("192.168.3.233", 1883) // MQTT 服务器IP+端口
.WithClientId("publish_client") // 客户端名称
//.WithProtocolVersion(MqttProtocolVersion.V500)
//.WithCleanSession()
.Build();
var response = await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
Console.WriteLine($"The MQTT client is connected. IsConnected: [{mqttClient.IsConnected}]");
Console.WriteLine(response.ResultCode);
// 2. 发布消息
// 2.1 在名为 topic2 的主题上发布消息 this is a test message
var applicationMessage = new MqttApplicationMessageBuilder()
.WithTopic("topic2")
.WithPayload("this is a test message")
.Build();
// 2.2 异步发布消息
await mqttClient.PublishAsync(applicationMessage, CancellationToken.None);
// 3. 断开连接
await mqttClient.DisconnectAsync();
Console.WriteLine("MQTT application message is published.");
}
i++;
Thread.Sleep(1000);
}
}
// 订阅消息
// 订阅一次就可以，不需要循环
// 当订阅的主题有发布消息时，这个程序就可以接收到
private static async Task SubscribeTopic()
{
var mqttFactory = new MqttFactory();
using (var mqttClient = mqttFactory.CreateMqttClient())
{
// 1. 设置连接 MQTT 服务器的属性
var mqttClientOptions = new MqttClientOptionsBuilder()
.WithTcpServer("192.168.3.233", 1883)
.WithClientId("subscribe_client")
//.WithCleanSession()
.Build();
// 2. 定义一个事件，当订阅的主题有发布消息时，接收并打印消息
// 2.1 这段代码必须写在连接 MQTT 服务器的代码之前，才能确保可以接收到消息
mqttClient.ApplicationMessageReceivedAsync += e =>
{
Console.WriteLine("Received application message.");
Console.WriteLine(e.ApplicationMessage.Topic);
Console.WriteLine(Encoding.UTF8.GetString(e.ApplicationMessage.Payload));
Console.WriteLine("===================");
return Task.CompletedTask;
};
// 3. 连接 MQTT 服务器
await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
// 4. 订阅名为 topic2 的主题的消息
var mqttSubscribeOptions = mqttFactory.CreateSubscribeOptionsBuilder()
.WithTopicFilter(
f =>
{
f.WithTopic("topic2")
.WithExactlyOnceQoS(); //即精准一次
})
.Build();
await mqttClient.SubscribeAsync(mqttSubscribeOptions, CancellationToken.None);
Console.WriteLine("MQTT client subscribed to topic.");
// 5. 离开时才断开连接
Console.WriteLine("Press enter to exit.");
Console.ReadLine();
}
}
}
}

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