MQTTNet UseApplicationMessageReceivedHandler未触发

Question

我正在做一个POC，所以这里是快速和肮脏的代码。我使用MQTT.fx桌面客户端来测试我的MQTT服务器的发布/订阅。工作正常。我可以发布/订阅我的主题。我可以从另一个mqtt客户端发布，并获得消息。使用此代码时，当我发布来自MQTT.fx或任何其他发布者的消息时，我不会收到任何消息。如果我使用mqttClient发布，我将收到一些信息(如果您取消对该行的注释)。我在挠头……有人能帮帮忙吗？谢谢。

class Program
{
    private static CancellationTokenSource cts = new CancellationTokenSource(); //TODO create token using the Timeout delay from config
    private static async Task Main(string[] args)
    {
        var factory = new MqttFactory();
        var mqttClient = factory.CreateMqttClient();
        var options = new MqttClientOptionsBuilder()
            .WithClientId("MyClientIDHere")
            .WithTcpServer("IPAddressHere", 1883)
            //.WithCredentials("Wbo", string.Empty)
            //.WithTls()
            .WithCleanSession()
            .Build();
        try
        {
            mqttClient.UseApplicationMessageReceivedHandler(async e =>
            {
                Console.WriteLine("### RECEIVED APPLICATION MESSAGE ###");
                Console.WriteLine($"+ Topic = {e.ApplicationMessage.Topic}");
                Console.WriteLine($"+ Payload = {Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}");
                Console.WriteLine($"+ QoS = {e.ApplicationMessage.QualityOfServiceLevel}");
                Console.WriteLine($"+ Retain = {e.ApplicationMessage.Retain}");
                Console.WriteLine();
            });
            mqttClient.UseConnectedHandler(async e =>
            {
                Console.WriteLine("### CONNECTED WITH SERVER ###");

                // Subscribe to a topic
                await mqttClient.SubscribeAsync(new TopicFilterBuilder().WithTopic("MyClientIDHere/Device_2/Instance_1").Build());

                Console.WriteLine("### SUBSCRIBED ###");
            });
            await mqttClient.ConnectAsync(options, cts.Token);
           // UNCOMMENT AND YOU WILL RECEIVE A MESSAGE Task.Run(() => mqttClient.PublishAsync("MyClientIDHere/Device_2/Instance_1","met=Temperature~data=29"));

        }

        catch (OperationCanceledException)
        {
            Console.WriteLine("task cancelled");   
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }

        Console.ReadKey();
    }
}

Answer 1

使用最新版本的MQTTnet，我无法重现您的问题，它似乎可以在这里工作。我使用的是一个蚊子MQTT服务器，它位于另一台服务器上，而不是我运行程序的服务器上。

你的代码看起来不错。您可以通过在连接之前订阅主题来改进某些内容。