HomeAssistantDiscoveryNet

This project contains two libraries that are both published to Nuget

1. HomeAssistantDiscoveryNet Library, contains all HA Discovery Documents
2. ToMqttNet a managed way to keep a MQTT connection in ASP.NET

HomeAssistantDiscoveryNet Library

Features:

• Support all Home Assistant Discovery (See full list below)
• De(serilization) using System.Text.Json source generators (AoT Compatible)

Contains the following Home Assistant MQTT Discovery Documents as C# classes:

• AlarmControlPanel
• BinarySensor
• Button
• Camera
• Climate
• Cover
• DefaultLight
• DeviceTracker
• DeviceTrigger
• Event
• Fan
• Humidifier
• Image
• JsonLight
• LawnMower
• Lock
• Number
• Scene
• Select
• Sensor
• Siren
• Switch
• TagScanner
• TemplateLight
• Text
• Update
• Vacuum
• Valve
• WaterHeater

This makes it easy to create discovery documents from C# without having to worry about mistyping property names etc.

How to serialize discovery docs

var cfg = new MqttBinarySensorDiscoveryConfig
{
    Name = $"Recommend Charging",
    ValueTemplate = "{{ 'ON' if value_json.recommend else 'OFF' }}",
    StateTopic = $"some-node/status/recommend-charging",
    UniqueId = $"some-node-recommend-charging",
};

var json = cfg.ToJson();

Results in

{
  "component": "binary_sensor",
  "state_topic": "some-node/status/recommend-charging",
  "value_template": "{{ 'ON' if value_json.recommend else 'OFF' }}",
  "name": "Recommend Charging",
  "unique_id": "some-node-recommend-charging"
}

How to deserialize discovery docs

var parser = new MqttDiscoveryConfigParser(NullLoggerFactory.Instance, []);
var topic = "some-node/binary/some_sensor";
var message = "{\"component\": \"binary_sensor\", \"state_topic\": \"some-node/status/recommend-charging\", \"value_template\": \"{{ 'ON' if value_json.recommend else 'OFF' }}\", \"name\": \"Recommend Charging\", \"unique_id\": \"some-node-recommend-charging\"}";

var result = parser.Parse(topic, message);

Assert.IsType<MqttBinarySensorDiscoveryConfig>(result);

ToMqttNet Library

This sets up a managed connection to a MQTT broker with

• Makes use of MQTTnet for the connection
• Dependency injection
• System.Diagnostics.Metrics Based metrics
• AoT compatible
• Home Assistant Discovery integration

How to set up the ToMqttNet Library

In Program.cs/Startup.cs

var builder = WebApplication.CreateSlimBuilder(args);

builder.Services.AddMqttConnection()
    .Configure<IOptions<MqttOptions>>((options, mqttConfI) =>
    {
        var mqttConf = mqttConfI.Value;
        options.NodeId = "myintegration";
        options.ClientOptions.ChannelOptions = new MqttClientTcpOptions
        {
            Server = mqttConf.Server,
            Port = mqttConf.Port,
        };
    });

// ...

How to use the ToMqttNet Library

// Remember to register this service in ASP.NET (Or call the .Execute)
public class CounterMqttBackgroundService(MqttConnectionService mqtt) : BackgroundService
{
    private readonly MqttConnectionService _mqtt = mqtt;

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        var discoveryDoc = new MqttSensorDiscoveryConfig()
        {
            UniqueId = "myintegration_mycounter",
            Name = "My Counter",
            ValueTemplate = "{{ value_json.value }}",
            StateTopic = _mqtt.MqttOptions.NodeId + "/status/counter", // myintegration/status/counter
        };

        await _mqtt.PublishDiscoveryDocument(discoveryDoc);

        var counter = 0L;
        while (!stoppingToken.IsCancellationRequested)
        {
            await _mqtt.PublishAsync(new MqttApplicationMessageBuilder()
                .WithTopic(_mqtt.MqttOptions.NodeId + "/status/counter")
                .WithPayload(JsonSerializer.Serialize(new {value = counter}))
                .Build());
            await Task.Delay(TimeSpan.FromMinutes(1), stoppingToken);
            counter++;
        }
    }
}

Examples / usages of HomeAssistantDiscoveryNet and ToMqttNet

• JonasMH/Dantherm2Mqtt