As I’m testing my Message Queue Telemetry Transport(MQTT) LoRa gateway I’m building a proof of concept(PoC) .Net core console application for each IoT platform I would like to support.
This PoC was to confirm that I could connect to the Bosch IoT Suite MQTT API then format topics and payloads correctly.
The Bosch IoT Hub MQTT broker, username, password, and clientID are the required command line parameters. For this PoC I ran out of time to get cloud to device (C2D) messaging or any presentation functionality working.
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SOFTWARE
A quick and dirty test client to explore how BoschIoT Suite MQTT connectivity works
*/
namespace devMobile.Mqtt.TestClient.BoschIoTSuite
{
using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Client.Disconnecting;
using MQTTnet.Client.Options;
using MQTTnet.Client.Receiving;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
class Program
{
private static IMqttClient mqttClient = null;
private static IMqttClientOptions mqttOptions = null;
private static string server;
private static string username;
private static string password;
private static string clientId;
static void Main(string[] args)
{
MqttFactory factory = new MqttFactory();
mqttClient = factory.CreateMqttClient();
if (args.Length != 4)
{
Console.WriteLine("[MQTT Server] [UserName] [Password] [ClientID]");
Console.WriteLine("Press <enter> to exit");
Console.ReadLine();
return;
}
server = args[0];
username = args[1];
password = args[2];
clientId = args[3];
mqttOptions = new MqttClientOptionsBuilder()
.WithTcpServer(server)
.WithCredentials(username, password)
.WithClientId(clientId)
.WithTls()
.Build();
mqttClient.UseDisconnectedHandler(new MqttClientDisconnectedHandlerDelegate(e => MqttClient_Disconnected(e)));
mqttClient.UseApplicationMessageReceivedHandler(new MqttApplicationMessageReceivedHandlerDelegate(e => MqttClient_ApplicationMessageReceived(e)));
mqttClient.ConnectAsync(mqttOptions).Wait();
string topicD2C = "telemetry";
while (true)
{
JObject payloadJObject = new JObject();
payloadJObject.Add("OfficeTemperature", "22." + DateTime.UtcNow.Millisecond.ToString());
payloadJObject.Add("OfficeHumidity", (DateTime.UtcNow.Second + 40).ToString());
string payload = JsonConvert.SerializeObject(payloadJObject);
Console.WriteLine($"Topic:{topicD2C} Payload:{payload}");
var message = new MqttApplicationMessageBuilder()
.WithTopic(topicD2C)
.WithPayload(payload)
.WithAtMostOnceQoS() // Anthing but this causes timeout
.WithRetainFlag()
.Build();
Console.WriteLine("PublishAsync start");
mqttClient.PublishAsync(message).Wait();
Console.WriteLine("PublishAsync finish");
Thread.Sleep(30100);
}
}
private static void MqttClient_ApplicationMessageReceived(MqttApplicationMessageReceivedEventArgs e)
{
Console.WriteLine($"ClientId:{e.ClientId} Topic:{e.ApplicationMessage.Topic} Payload:{e.ApplicationMessage.ConvertPayloadToString()}");
}
private static async void MqttClient_Disconnected(MqttClientDisconnectedEventArgs e)
{
Debug.WriteLine("Disconnected");
await Task.Delay(TimeSpan.FromSeconds(5));
try
{
await mqttClient.ConnectAsync(mqttOptions);
}
catch (Exception ex)
{
Debug.WriteLine("Reconnect failed {0}", ex.Message);
}
}
}
}
The bosch IoT Hub device configuration was via a swagger API but I need to spend some more time figuring out how to configure the data analysis and presentation tools.
I adapted the steps in the IoT Hub Documentation for Sending Device Data using MQTT. The first step was to create a free Hub subscription.
Then using the device registry swagger UI page to add a new device.
After a couple of failed attempts I worked out the format of the Authorisation details (I think the username format in the online documentation might be wrong)
Of the 10+ SaaS IoT services I have setup the Bosch IoT Suite was the hardest to get working. I think this was becuase it is meant to be managed via the API from a in-house application. In a future post I’ll get configure the cloud to device messaging, plus analysis and display functionality.
