使用 HTTP POST 请求将遥测消息发送到 Azure IoT Central 设备

Question

我正在尝试使用 HTTP POST 请求将遥测数据发送到 Azure IoT Central 中的设备。

类似的 Rest API 可用于 Azure IoT 中心 - https://learn.microsoft.com/en-us/rest/api/iothub/device/send-device-event

我能够使用此网站提取 Azure IoT Central 背后的 IoT 中心资源 URL - <一href="https://dpsgen.z8.web.core.windows.net/" rel="nofollow noreferrer">https://dpsgen.z8.web.core.windows.net/

它需要范围我们从 Azure IoT Central 获取的 ID、设备 ID 和设备主键。它为您提供 IoT 中心连接字符串

HostName=iotc-<>.azure-devices.net;DeviceId=<>; SharedAccessKey=<>

使用上述 IoT 中心主机名，我尝试了 IoT 中心发送设备事件 Rest API。它因未经授权的错误而失败。

我正在使用从 Azure IoT Central 应用程序中的以下路径生成的 SAS 令牌

Azure IoT 中心 ->权限-> API 令牌 -> “应用程序管理员”角色

任何帮助都会有用。

Answer 1

看看我的 answer 其中详细描述了如何生成连接信息以使用 REST Post 请求将遥测数据发送到 Azure IoT Central 应用程序。

以下是更新的 Azure 函数，用于生成请求的设备连接信息：

#r "Newtonsoft.Json"

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Net.Http;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Web;


public static async Task<IActionResult> Run(HttpRequest req, ILogger log)
{
    int retryCounter = 10;
    int pollingTimeInSeconds = 3;

    string deviceId = req.Query["deviceid"];
    string mid = req.Query["modelid"];
               
    log.LogInformation($"DeviceId = {deviceId}, ModelId = {mid}");

    if (!Regex.IsMatch(deviceId, @"^[a-z0-9\-]+$"))
        throw new Exception($"Invalid format: DeviceID must be alphanumeric, lowercase, and may contain hyphens");

    string iotcScopeId = System.Environment.GetEnvironmentVariable("AzureIoTC_scopeId");      
    string iotcSasToken = System.Environment.GetEnvironmentVariable("AzureIoTC_sasToken");    
            
    if(string.IsNullOrEmpty(iotcScopeId) || string.IsNullOrEmpty(iotcSasToken))
        throw new ArgumentNullException($"Missing the scopeId and/or sasToken of the IoT Central App");

    string deviceKey = SharedAccessSignatureBuilder.ComputeSignature(iotcSasToken, deviceId);
 
    string address = $"https://global.azure-devices-provisioning.net/{iotcScopeId}/registrations/{deviceId}/register?api-version=2021-06-01";
    string sas = SharedAccessSignatureBuilder.GetSASToken($"{iotcScopeId}/registrations/{deviceId}", deviceKey, "registration");
 
    log.LogInformation($"sas_token: {sas}");

    using (HttpClient client = new HttpClient())
    {
        client.DefaultRequestHeaders.Add("Authorization", sas);
        client.DefaultRequestHeaders.Add("accept", "application/json");
        string jsontext = string.IsNullOrEmpty(mid) ? null : $"{{ \"modelId\": \"{mid}\" }}";
        var response = await client.PutAsync(address, new StringContent(JsonConvert.SerializeObject(new { registrationId = deviceId, payload = jsontext }), Encoding.UTF8, "application/json"));

        var atype = new { errorCode = "", message = "", operationId = "", status = "", registrationState = new JObject() };
        do
        {
            dynamic operationStatus = JsonConvert.DeserializeAnonymousType(await response.Content.ReadAsStringAsync(), atype);
            if (!string.IsNullOrEmpty(operationStatus.errorCode))
            {
                throw new Exception($"{operationStatus.errorCode} - {operationStatus.message}");
            }
            response.EnsureSuccessStatusCode();
            if (operationStatus.status == "assigning")
            {
                Task.Delay(TimeSpan.FromSeconds(pollingTimeInSeconds)).Wait();
                address = $"https://global.azure-devices-provisioning.net/{iotcScopeId}/registrations/{deviceId}/operations/{operationStatus.operationId}?api-version=2021-06-01";
                response = await client.GetAsync(address);
            }
            else if (operationStatus.status == "assigned")
            {
                log.LogInformation($"{JsonConvert.SerializeObject(operationStatus, Formatting.Indented)}");
                string assignedHub = operationStatus.registrationState.assignedHub;
                string cstr = $"HostName={assignedHub};DeviceId={operationStatus.registrationState.deviceId};SharedAccessKey={deviceKey}"; // + (string.IsNullOrEmpty(mid) ? "" : $";modelId={mid.Replace(";","#")}"); 
                string requestUrl = $"https://{assignedHub}/devices/{operationStatus.registrationState.deviceId}/messages/events?api-version=2021-04-12";
                string deviceSasToken = SharedAccessSignatureBuilder.GetSASToken($"{assignedHub}/{operationStatus.registrationState.deviceId}", deviceKey);

                log.LogInformation($"IoTC DeviceConnectionString:\n\t{cstr}");
                return new OkObjectResult(JObject.FromObject(new { iotHub = assignedHub, iotFireUrl = requestUrl, deviceSasToken = deviceSasToken, deviceConnectionString = cstr }));
            }
            else
            {
                throw new Exception($"{operationStatus.registrationState.status}: {operationStatus.registrationState.errorCode} - {operationStatus.registrationState.errorMessage}");
            }
        } while (--retryCounter > 0);

        throw new Exception("Registration device status retry timeout exprired, try again.");
    } 
}

public sealed class SharedAccessSignatureBuilder
{
    public static string GetHostNameNamespaceFromConnectionString(string connectionString)
    {
        return GetPartsFromConnectionString(connectionString)["HostName"].Split('.').FirstOrDefault();
    }
    public static string GetSASTokenFromConnectionString(string connectionString, uint hours = 24)
    {
        var parts = GetPartsFromConnectionString(connectionString);
        if (parts.ContainsKey("HostName") && parts.ContainsKey("SharedAccessKey"))
            return GetSASToken(parts["HostName"], parts["SharedAccessKey"], parts.Keys.Contains("SharedAccessKeyName") ? parts["SharedAccessKeyName"] : null, hours);
        else
            return string.Empty;
    }
    public static string GetSASToken(string resourceUri, string key, string keyName = null, uint hours = 24)
    {
        try
        {
            var expiry = GetExpiry(hours);
            string stringToSign = System.Web.HttpUtility.UrlEncode(resourceUri) + "\n" + expiry;
            var signature = SharedAccessSignatureBuilder.ComputeSignature(key, stringToSign);
            var sasToken = keyName == null ?
                String.Format(CultureInfo.InvariantCulture, "SharedAccessSignature sr={0}&sig={1}&se={2}", HttpUtility.UrlEncode(resourceUri), HttpUtility.UrlEncode(signature), expiry) :
                String.Format(CultureInfo.InvariantCulture, "SharedAccessSignature sr={0}&sig={1}&se={2}&skn={3}", HttpUtility.UrlEncode(resourceUri), HttpUtility.UrlEncode(signature), expiry, keyName);
            return sasToken;
        }
        catch
        {
            return string.Empty;
        }
    }

    #region Helpers
    public static string ComputeSignature(string key, string stringToSign)
    {
        using (HMACSHA256 hmac = new HMACSHA256(Convert.FromBase64String(key)))
        {
            return Convert.ToBase64String(hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign)));
        }
    }

    public static Dictionary<string, string> GetPartsFromConnectionString(string connectionString)
    {
        return connectionString.Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries).Select(s => s.Split(new[] { '=' }, 2)).ToDictionary(x => x[0].Trim(), x => x[1].Trim(), StringComparer.OrdinalIgnoreCase);
    }

    // default expiring = 24 hours
    private static string GetExpiry(uint hours = 24)
    {
        TimeSpan sinceEpoch = DateTime.UtcNow - new DateTime(1970, 1, 1);
        return Convert.ToString((ulong)sinceEpoch.TotalSeconds + 3600 * hours);
    }

    public static DateTime GetDateTimeUtcFromExpiry(ulong expiry)
    {
        return (new DateTime(1970, 1, 1)).AddSeconds(expiry);
    }
    public static bool IsValidExpiry(ulong expiry, ulong toleranceInSeconds = 0)
    {
        return GetDateTimeUtcFromExpiry(expiry) - TimeSpan.FromSeconds(toleranceInSeconds) > DateTime.UtcNow;
    }

    public static string CreateSHA256Key(string secret)
    {
        using (var provider = new SHA256CryptoServiceProvider())
        {
            byte[] keyArray = provider.ComputeHash(UTF8Encoding.UTF8.GetBytes(secret));
            provider.Clear();
            return Convert.ToBase64String(keyArray);
        }
    }

    public static string CreateRNGKey(int keySize = 32)
    {
        byte[] keyArray = new byte[keySize];
        using (var provider = new RNGCryptoServiceProvider())
        {
            provider.GetNonZeroBytes(keyArray);
        }
        return Convert.ToBase64String(keyArray);
    }
    #endregion
}

Answer 2

IoT Central API 令牌用于管理应用程序功能，不能由设备使用。在 IoT Central 中选择设备，然后单击顶部的“连接”菜单，使用该设备显示的主键。

附带说明一下，尽管 https 支持设备，但由于其轮询性质，它不太适合 IoT，并且不支持设备孪生所需或报告的属性。 https://learn.microsoft。 com/en-us/azure/iot-hub/iot-hub-devguide-d2c-guidance

IoT Central 提供内置高可用性，底层 IoTHub 名称可以更改，因此需要手动获取不建议使用 IoTHub 名称。始终拨打 DPS 来检索 IoTHub 名称、第一次、定期或出现错误情况。