MQTTnet

MQTTnet is a .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker). The implementation is based on the documentation from http://mqtt.org/.

Features

General

Async support
TLS 1.2 support for client and server (but not UWP servers)
Extensible communication channels (i.e. In-Memory, TCP, TCP+TLS, WS)
Lightweight (only the low level implementation of MQTT, no overhead)
Performance optimized (processing ~25.000 messages / second)*
Interfaces included for mocking and testing
Access to internal trace messages
Unit tested (57+ tests)

* Tested on local machine with MQTTnet client and server running on the same machine using the TCP channel.

Client

Rx support (via another project)
Communication via TCP (+TLS) or WS (WebSocket)

Server (broker)

List of connected clients available
Supports connected clients with different protocol versions at the same time
Able to publish its own messages (no loopback client required)
Able to receive every messages (no loopback client required)
Extensible client credential validation

Supported frameworks

.NET Standard 1.3+
.NET Core 1.1+
.NET Core App 1.1+
.NET Framework 4.5.2+ (x86, x64, AnyCPU)
Universal Windows (UWP) 10.0.10240+ (x86, x64, ARM, AnyCPU)

Supported MQTT versions

3.1.1
3.1.0

Nuget

This library is available as a nuget package: https://www.nuget.org/packages/MQTTnet/

Contributions

If you want to contribute to this project just create a pull request.

References

This library is used in the following projects:

MQTT Client Rx (Wrapper for Reactive Extensions, https://github.com/1iveowl/MQTTClient.rx)
HA4IoT (Open Source Home Automation system for .NET, https://github.com/chkr1011/HA4IoT)

If you use this library and want to see your project here please let me know.

Examples

MqttClient

var options = new MqttClientOptions
{
    Server = "localhost"
};

var client = new MqttClientFactory().CreateMqttClient(options);
client.ApplicationMessageReceived += (s, 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();
};

client.Connected += async (s, e) =>
{
    Console.WriteLine("### CONNECTED WITH SERVER, SUBSCRIBING ###");

    await client.SubscribeAsync(new List<TopicFilter>
    {
        new TopicFilter("#", MqttQualityOfServiceLevel.AtMostOnce)
    });
};

client.Disconnected += async (s, e) => 
{
    Console.WriteLine("### DISCONNECTED FROM SERVER ###");
    await Task.Delay(TimeSpan.FromSeconds(5));

    try
    {
        await client.ConnectAsync();
    }
    catch
    {
        Console.WriteLine("### RECONNECTING FAILED ###");
    }
};

try
{
    await client.ConnectAsync();
}
catch
{
    Console.WriteLine("### CONNECTING FAILED ###");
}

Console.WriteLine("### WAITING FOR APPLICATION MESSAGES ###");

var messageFactory = new MqttApplicationMessageFactory();
while (true)
{
    Console.ReadLine();

    var applicationMessage = messageFactory.CreateApplicationMessage("myTopic", "Hello World", MqttQualityOfServiceLevel.AtLeastOnce);
    await client.PublishAsync(applicationMessage);
}

MqttServer

var options = new MqttServerOptions
{
    ConnectionValidator = p =>
    {
        if (p.ClientId == "SpecialClient")
        {
            if (p.Username != "USER" || p.Password != "PASS")
            {
                return MqttConnectReturnCode.ConnectionRefusedBadUsernameOrPassword;
            }
        }

        return MqttConnectReturnCode.ConnectionAccepted;
    }
};

var mqttServer = new MqttServerFactory().CreateMqttServer(options);
mqttServer.Start();

Console.WriteLine("Press any key to exit.");
Console.ReadLine();

mqttServer.Stop();

flattech / MQTTnet