SRF.Network.Mqtt 0.9.3

DI wrapper for MQTTnet Client

Context

SRF.Network.Mqtt aims to provide simple use of MQTTnet with dependency injection.

It's minimalistic in flexibility and for trivial use cases only. It was developed as a service in a particular application before carving the code out as a dedicated library.

Present code allows only 1 broker to be connected to. In order to connect to multiple brokers, the library would need to be expanded e.g. relying on keyed singleton services and a logic to select the configuration section according the service registration key.

Package

dotnet add package SRF.Network.Mqtt

Usage

during app setup:

use SRF.Network.Mqtt.Hosting;

IHostBuilder hostBuilder = ...
hostBuilder.AddMqtt()

The configurable properties can be found in SRF.Network.Mqtt.MqttOptions. A minimalistic config section in appsettings.json or an other suitable place may look as follows:

    "Mqtt": {
        "Host": "my.broker.host.org",
        "UseTls": false,
        "User": "...",
        "Pass": "..."
    }

then inject IMqttBrokerConnection to your services.

To publish messages, use

public class MyPublishingLogic(IMqttBrokerConnection brokerConnection)
{
    readonly IMqttBrokerConnection brokerConn = brokerConnection;

    public void SendIt<TObject>(TObject message) where TObject : class
    {
        var topic = "my/topic/for/message";
        var publishingQueueItem = brokerConn.PublishJson(topic, message);
        publishingQueueItem.Published += MessagePublishedHandler; // can be skipped
    }

    private void MessagePublishedHandler(object sender, PublishEventArgs args)
    {
        // ...
    }
}

The Publish and PublishJson methods of the MqttBrokerConnection implementation of IMqttBrokerConnection are non-blocking. They queue the item for subsequent publishing by another Task / Thread.

Use an IPublisher implementation passed to the corresponding IMqttBrokerConnection.Publish method for fine-grained control of the publishing details. The following IPublisher implementations are available in the library (as of 0.9.0): PublisherString, PublisherJson