标签：mqttClient 3.563 share MqttNet version sheet new data se

@@mqttnet 4.1.4 The formal environment cannot receive messages

 

 

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Following this example I have now therefore been required to update the MQTT.NET from version 3 (that works thanks the provided help) to version 4.

A very basic set of capabilities would be enough:

1. Connect to an adress with a timeout
2. Check if the connection has gone well
3. Receive messages
4. check disconnection

that was extremely easy in version 3

MqttClientOptionsBuilder builder = new MqttClientOptionsBuilder()
                                .WithClientId("IoApp" + HelperN.MQTT.GetClientID(true))
                                .WithTcpServer("localhost", 1883);

ManagedMqttClientOptions options = new ManagedMqttClientOptionsBuilder()
                                .WithAutoReconnectDelay(TimeSpan.FromSeconds(60))
                                .WithClientOptions(builder.Build())
                                .Build();

mqttClient = new MqttFactory().CreateManagedMqttClient();

mqttClient.ConnectedHandler = new MqttClientConnectedHandlerDelegate(OnConnected);
mqttClient.DisconnectedHandler = new MqttClientDisconnectedHandlerDelegate(OnDisconnected);
mqttClient.ConnectingFailedHandler = new ConnectingFailedHandlerDelegate(OnConnectingFailed);

mqttClient.SubscribeAsync(...);
mqttClient.SubscribeAsync(...);
mqttClient.StartAsync(options).GetAwaiter().GetResult();

mqttClient.UseApplicationMessageReceivedHandler(args => { OnMessageReceived(args); });

but when it comes to version 4 if I have to relay on those examples I have problems. Let's start from the connection

public static async Task Connect_Client_Timeout()
{
    /*
     * This sample creates a simple MQTT client and connects to an invalid broker using a timeout.
     * 
     * This is a modified version of the sample _Connect_Client_! See other sample for more details.
     */

    var mqttFactory = new MqttFactory();
    strError = String.Empty;

    using (var mqttClient = mqttFactory.CreateMqttClient())
    {
        var mqttClientOptions = new MqttClientOptionsBuilder().WithTcpServer("aaaa127.0.0.1",1883).Build();

        try
        {
                
            using (var timeoutToken = new CancellationTokenSource(TimeSpan.FromSeconds(5)))
            {
                await mqttClient.ConnectAsync(mqttClientOptions, timeoutToken.Token);
            }
        }
        catch (OperationCanceledException exc)
        {
            strError = "Connect_Client_Timeout exc:" + exc.Message;
        }
    }
}

And I call this task from the main awaiting the result.

var connectTask  = Connect_Client_Timeout();
connectTask.Wait();<-----never ends

Since I put a wrong address "aaaa127.0.0.1" I expect a failure after 5 seconds. But the connectTask.Wait never end. But even if I put the right address "127.0.0.1" it never exits. So perhaps the error stands in the connectTask.Wait();.

Thanks

• c#
• async-await
• task
• connect
• mqttnet

Share Improve this question Follow   edited Dec 21, 2022 at 11:03     asked Dec 21, 2022 at 10:37 Luca 89811 gold badge1313 silver badges3030 bronze badges Add a comment

1 Answer

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The solution is here In short you have to do this:

static async Task  Connect()
{
    IManagedMqttClient _mqttClient = new MqttFactory().CreateManagedMqttClient();

    // Create client options object
    MqttClientOptionsBuilder builder = new MqttClientOptionsBuilder()
                                        .WithClientId("behroozbc")
                                        .WithTcpServer("localhost");
    ManagedMqttClientOptions options = new ManagedMqttClientOptionsBuilder()
                                .WithAutoReconnectDelay(TimeSpan.FromSeconds(60))
                                .WithClientOptions(builder.Build())
                                .Build();



    // Set up handlers
    _mqttClient.ConnectedAsync += _mqttClient_ConnectedAsync;


    _mqttClient.DisconnectedAsync += _mqttClient_DisconnectedAsync;


    _mqttClient.ConnectingFailedAsync += _mqttClient_ConnectingFailedAsync;


    // Connect to the broker
    await _mqttClient.StartAsync(options);

    // Send a new message to the broker every second
    while (true)
    {
        string json = JsonSerializer.Serialize(new { message = "Hi Mqtt", sent = DateTime.UtcNow });
        await _mqttClient.EnqueueAsync("behroozbc.ir/topic/json", json);

        await Task.Delay(TimeSpan.FromSeconds(1));
    }
    Task _mqttClient_ConnectedAsync(MqttClientConnectedEventArgs arg)
    {
        Console.WriteLine("Connected");
        return Task.CompletedTask;
    };
    Task _mqttClient_DisconnectedAsync(MqttClientDisconnectedEventArgs arg)
    {
        Console.WriteLine("Disconnected");
        return Task.CompletedTask;
    };
    Task _mqttClient_ConnectingFailedAsync(ConnectingFailedEventArgs arg)
    {
        Console.WriteLine("Connection failed check network or broker!");
        return Task.CompletedTask;
    }
}

and then just call Connect() and rely on the subscribed examples

Share Improve this answer Follow   answered Dec 21, 2022 at 12:56    

MQTT Client with MQTTnet 4 and C#

TABLE OF CONTENTS

• Create a project

• Install Dependency

• Implementation

• Conclusion

In the previous post, we worked with MQTTnet version 3, although version 4 of MQTTnet came in Jun 2022. As MQTTnet version 4 has a lot of changes, I thought it would be helpful to write a new article about developing a simple MQTT client using this version. To find more information on MQTT and what is MQTT client and broker please check this post.

Create a project

We need to create a console project. I use dotnet CLI to create a new project.

COPY

dotnet new console --name SimpleMQTTClient4

Now We have a new empty project to code an MQTT client.

Install Dependency

To work in dotnet with MQTT Client, we need to install the MQTTnet.Extensions.ManagedClient package from NuGet. This article uses version 4.

COPY

dotnet add package MQTTnet.Extensions.ManagedClient --version 4.0.2.221

Implementation

Open Program.cs.Add the below code.

COPY

using MQTTnet.Client;
using MQTTnet.Extensions.ManagedClient;
using MQTTnet;
using System.Text.Json;

IManagedMqttClient _mqttClient = new MqttFactory().CreateManagedMqttClient();

// Create client options object
MqttClientOptionsBuilder builder = new MqttClientOptionsBuilder()
                                        .WithClientId("behroozbc")
                                        .WithTcpServer("localhost");
ManagedMqttClientOptions options = new ManagedMqttClientOptionsBuilder()
                        .WithAutoReconnectDelay(TimeSpan.FromSeconds(60))
                        .WithClientOptions(builder.Build())
                        .Build();



// Set up handlers
_mqttClient.ConnectedAsync += _mqttClient_ConnectedAsync;


_mqttClient.DisconnectedAsync += _mqttClient_DisconnectedAsync;


_mqttClient.ConnectingFailedAsync += _mqttClient_ConnectingFailedAsync;


// Connect to the broker
await _mqttClient.StartAsync(options);

// Send a new message to the broker every second
while (true)
{
    string json = JsonSerializer.Serialize(new { message = "Hi Mqtt", sent = DateTime.UtcNow });
    await _mqttClient.EnqueueAsync("behroozbc.ir/topic/json", json);

    await Task.Delay(TimeSpan.FromSeconds(1));
}
Task _mqttClient_ConnectedAsync(MqttClientConnectedEventArgs arg)
{
    Console.WriteLine("Connected");
    return Task.CompletedTask;
};
Task _mqttClient_DisconnectedAsync(MqttClientDisconnectedEventArgs arg)
{
    Console.WriteLine("Disconnected");
    return Task.CompletedTask;
};
Task _mqttClient_ConnectingFailedAsync(ConnectingFailedEventArgs arg)
{
    Console.WriteLine("Connection failed check network or broker!");
    return Task.CompletedTask;
}

By default MQTT without encryption port is 1883. If you want to change it, add a parameter port number to WithTcpServer.

COPY

// Create the options for MQTT Broker
var options = new MqttServerOptionsBuilder()
    //Set endpoint to localhost
    .WithDefaultEndpoint()
    // Port is going to use 5004
    .WithDefaultEndpointPort(5004);

Conclusion

You have an MQTT client. I hope it was helpful. In this post, I will show you how to create a broker to test it.

You find this project on Github.

If you are still unsure of what to do or if you got any errors, I suggest you use the comment section below and let me know! I’m here to help.

     

标签：mqttClient,3.563,share,MqttNet,version,sheet,new,data,se
From： https://www.cnblogs.com/wl-blog/p/17545698.html