Mqtt isConnected 属性为 false 但收到消息

Question

我正在尝试使用 MQTTnet 连接到 Mosquitto。我能够接收消息，但

IsConnected

属性是

false

。有人知道为什么吗？ 仅属性

iStart

设置为

true

。 问题似乎出在 Mosquitto 主机上。

mosquitto.conf

大多是默认值。我只设置了这些参数：

allow_anonymous true
password_file C:\mosquitto\passwd
tls_version tlsv1.2
log_dest file C:\mosquitto\log\mosquitto.log

日志文件为空。

class Program
    {
        static async Task Main()
        {
            var mqttClientId = "MyClientId";             // Unique ClientId or pass a GUID as string for something random
            var mqttBrokerAddress = "localhost";         // hostname or IP address of your MQTT broker
            var mqttBrokerUsername = "guest";       // Broker Auth username if using auth
            var mqttBrokerPassword = "guest";       // Broker Auth password if using auth
            var topic = "topic";                 // topic to subscribe to
            var mqttClient = new MqttFactory().CreateManagedMqttClient();
            var mqttClientOptions = new ManagedMqttClientOptionsBuilder()
                        .WithAutoReconnectDelay(TimeSpan.FromSeconds(5))
                        .WithClientOptions(new MqttClientOptionsBuilder()
                            .WithTcpServer(mqttBrokerAddress, 1883)
                            .WithCredentials(mqttBrokerUsername, mqttBrokerPassword)    // Remove this line if no auth
                            .WithCleanSession().WithKeepAlivePeriod(new TimeSpan(1))//.WithTls(tlsOptions)
                            .Build()
                        )
                        .Build();

            mqttClient.ApplicationMessageReceivedAsync += async e => MqttOnNewMessage(e);
            mqttClient.ConnectedAsync += async e => MqttOnConnected(e);
            mqttClient.DisconnectedAsync += async e => MqttOnDisconnected(e);
            mqttClient.SynchronizingSubscriptionsFailedAsync += async e => test(e);
            mqttClient.ConnectingFailedAsync += async e => test2(e);
            var aaa = new List<MqttTopicFilter>();
            var bbb = new MqttTopicFilterBuilder().WithTopic(topic).Build();
            aaa.Add(bbb);
            try
            {
                await mqttClient.SubscribeAsync(aaa);
                await mqttClient.StartAsync(mqttClientOptions);
                System.Console.WriteLine(mqttClient.IsConnected); 
            }
            catch (Exception ex)
            {

                throw;
            }
            Console.ReadLine();
        }

        private static void test2(ConnectingFailedEventArgs e)
        {
            Console.WriteLine();
        }

        private static void test(ManagedProcessFailedEventArgs e)
        {
            Console.WriteLine();
        }

        private static void MqttOnNewMessage(MqttApplicationMessageReceivedEventArgs e)
        {
            // Do something with each incoming message from the topic

            Console.WriteLine($"MQTT Client: OnNewMessage Topic: {e.ApplicationMessage.Topic} / Message: {e.ApplicationMessage.Payload}");
        }

        private static void MqttOnConnected(MqttClientConnectedEventArgs e) => Console.WriteLine($"MQTT Client: Connected with result: {e.ConnectResult.ResultCode}");

        private static void MqttOnDisconnected(MqttClientDisconnectedEventArgs e) => Console.WriteLine($"MQTT Client: Broker connection lost with reason: {e.Reason}.");
    }

Answer 1

问题似乎与 MQTTNet 上的保持活动属性有关。 对我来说，它通过设置

得到了修复

.WithKeepAlivePeriod(时间)

我的

属性

MqttClientOptionBuilder()

时间跨度为 60 瑞典克朗

var 时间 = TimeSpan.FromSeconds(60);

这就是我可以为 MqttNet github 的问题收集的内容： https://github.com/dotnet/MQTTnet/issues/1290#issuecomment-968064210