How to use IoT Hub SDK from Azure C# function app

Question

I need to wrap Azure IoT Hub SDK calls in a C# function app with HTTP trigger to provide a validation service to confirm successful IoT Device provisioning. Would like to see an example of how to instantiate a ServiceClient type object against my IoT Hub, which can then be used to retrieve device details (to confirm that the specified device exists in the IoT Hub Registry.)

Answer 1

Hi @Hocker, Cary Greetings! Welcome to Microsoft Q&A forum. Thank you for posting this question here.

Here is an Azure function sample code to achieve what you are looking for

using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Microsoft.Azure.Devices;

namespace Raj.ServiceClient
{
    public static class IoTServiceClient
    {
        private static RegistryManager _registryManager;

        [FunctionName("IoTServiceClient")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");

            if (_registryManager == null)
            {
                // Connection string for the IoT Hub
                string connectionString = "<IoTHubOwnerConnectionString>";

                // Create a new instance of RegistryManager using the IoT Hub connection string
                _registryManager = RegistryManager.CreateFromConnectionString(connectionString);
            }
            
            string deviceId = req.Query["deviceId"];

            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            deviceId = deviceId ?? data?.name;

            // Check if the device exists
            Device device = await _registryManager.GetDeviceAsync(deviceId);
            if (device == null)
            {
                // Device does not exist
                Console.WriteLine($"Device with ID {deviceId} does not exist.");
            }
            else
            {
                // Device exists
                Console.WriteLine($"Device with ID {deviceId} exists.");
            }

            string responseMessage = string.IsNullOrEmpty(deviceId)
                ? $"Hello, {deviceId} does not exists."
                : $"Hello, {deviceId} exists.";

            return new OkObjectResult(responseMessage);
        }
    }
}

I have tested this function locally and you can pass the device ID as a query parameter to invoke the HTPP trigger function as follows http://localhost:7071/api/IoTServiceClient?deviceid=TestDevice4. Please find the below snippet from the function execution stack.

Hope this helps. Please let us know if you have any additional questions or need further assistance.

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