MQTTnet/Samples/Client/Client_Publish_Samples.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using MQTTnet.Client;

namespace MQTTnet.Samples.Client;

public static class Client_Publish_Samples
{
    public static async Task Publish_Application_Message()
    {
        /*
         * This sample pushes a simple application message including a topic and a payload.
         *
         * Always use builders where they exist. Builders (in this project) are designed to be
         * backward compatible. Creating an _MqttApplicationMessage_ via its constructor is also
         * supported but the class might change often in future releases where the builder does not
         * or at least provides backward compatibility where possible.
         */

        var mqttFactory = new MqttFactory();

        using (var mqttClient = mqttFactory.CreateMqttClient())
        {
            var mqttClientOptions = new MqttClientOptionsBuilder()
                .WithTcpServer("broker.hivemq.com")
                .Build();

            await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);

            var applicationMessage = new MqttApplicationMessageBuilder()
                .WithTopic("samples/temperature/living_room")
                .WithPayload("19.5")
                .Build();

            await mqttClient.PublishAsync(applicationMessage, CancellationToken.None);

            Console.WriteLine("MQTT application message is published.");
        }
    }
}