MQTTStudy/MQTTSample/MqttMultiTopicClientApp/Program.cs

using PMqttClient;

namespace MqttMultiTopicClientApp
{
    internal class Program
    {
        private static string SERVER_IP = "localhost";
        private static readonly int PORT = 1883;

        private static MqttMultiTopicClient _mqttClient;

        static async Task Main(string[] args)
        {
            _mqttClient = new MqttMultiTopicClient();
            _mqttClient.LogHandler += MqttClient_LogHandler;
            _mqttClient.MessageHandler += MqttClient_MessageHandler;

            await _mqttClient.AddTopicAsync("home/livingroom/temperature", MqttQoSLevel.AtLeastOnce);

            await Task.Delay(1000);

            await _mqttClient.ConnectAsync(SERVER_IP, PORT, $"cid_{Random.Shared.Next(1, 1000)}");
            
            await _mqttClient.AddTopicAsync("home/bedroom/humidity", MqttQoSLevel.AtMostOnce);
            await _mqttClient.AddTopicAsync("home/kitchen/temperature", MqttQoSLevel.AtMostOnce);

            while (true)
            {
                Console.WriteLine();
                Console.WriteLine("----------------------");
                Console.WriteLine("Add topic(1)");
                Console.WriteLine("Publish message(2)");
                Console.WriteLine("Else: Exit");
                Console.WriteLine("----------------------");
                Console.Write(">");
                string command = Console.ReadLine();
                await HandleCommand(command);
            }
        }

        private static void MqttClient_MessageHandler(object? sender, string e)
        {
            Console.WriteLine($"[Message] {e}");
        }

        private static void MqttClient_LogHandler(object? sender, string e)
        {
            Console.WriteLine($"[Log] {e}");
        }

        static async Task HandleCommand(string command)
        {
            if (command.Contains("1", StringComparison.InvariantCultureIgnoreCase))
            {
                Console.WriteLine("Topic?");
                Console.Write(">");
                string topic = Console.ReadLine();
                Console.WriteLine("QoS(0-2)");
                Console.Write(">");
                string qos = Console.ReadLine();
                int.TryParse(qos, out int convertedQos);
                await _mqttClient.AddTopicAsync(topic, (MqttQoSLevel)convertedQos);
            }
            else if (command.Contains("2", StringComparison.InvariantCultureIgnoreCase))
            {
                Console.WriteLine("Topic?");
                Console.Write(">");
                string topic = Console.ReadLine();
                Console.WriteLine("Message?");
                Console.Write(">");
                string message = Console.ReadLine();
                Console.WriteLine("QoS(0-2)");
                Console.Write(">");
                string qos = Console.ReadLine();
                int.TryParse(qos, out int convertedQos);
                await _mqttClient.PubishAsync(topic, message, (MqttQoSLevel)convertedQos);
            }
            else
            {
                await _mqttClient.DisconnectAsync();
            }
        }
    }
}