从ServiceBus触发的azure功能中检索IoT Hub Twin

1 回答

• 1

  Azure IoT Hub设备到 Cloud 消息格式描述为here . 这种格式没有设备双胞胎属性 . 设备双胞胎存储在 Cloud 后端中，可以根据到特定 endpoints （内置和/或自定义 endpoints ）的iot中心路由通知其更改 .

  您的函数“TestQueueTrigger”的示例正在使用azure-functions-iothub-extension用于版本1.扩展输入绑定 Twin 允许使用扩展中的单独调用来获取设备twin：

  deviceTwin = await registryManager.GetTwinAsync(attribute.DeviceId);
  

  基本上，此扩展也可用于ServiceBusTrigger绑定 . 请注意，此扩展只能用于功能版本1，因此我建议使用例如REST API Get Twin调用在设备中使用设备 .

  Update

  以下代码段显示了ServiceBusTrigger函数和REST API Get Twin调用的示例 .

  run.csx文件：

  #r "..\\bin\\Microsoft.Azure.ServiceBus.dll"
  #r "..\\bin\\Microsoft.Azure.Devices.Shared.dll"
  #r "Microsoft.Azure.WebJobs.ServiceBus"
  #r "Newtonsoft.Json"
  
  
  using System;
  using System.Threading.Tasks;
  using System.Text;
  using Newtonsoft.Json;
  using Newtonsoft.Json.Linq;
  using Microsoft.Azure.WebJobs.ServiceBus;
  using Microsoft.Azure.ServiceBus;
  using System.Globalization;
  using System.Linq;
  using System.Net.Http;
  using System.Security.Cryptography;
  using System.Web;
  using Microsoft.Azure.Devices.Shared;
  
  // reusable proxy
  static HttpClientHelper iothub = new HttpClientHelper(Environment.GetEnvironmentVariable("AzureIoTHubShariedAccessPolicy"));
  
  public static async Task Run(Message queueItem, ILogger log)
  {
      // payload
      log.LogInformation($"C# ServiceBus queue trigger function processed message: {Encoding.UTF8.GetString(queueItem.Body)}");
  
      // device identity Id
      var deviceId = queueItem.UserProperties["iothub-connection-device-id"];
  
      // get the device twin
      var response = await iothub.Client.GetAsync($"/twins/{deviceId}?api-version=2018-06-30");
      response.EnsureSuccessStatusCode();
      Twin twin = await response.Content.ReadAsAsync<Twin>();
  
      log.LogInformation(JsonConvert.SerializeObject(twin.Tags, Formatting.Indented));
  
      await Task.CompletedTask;
  }
  
  
  // helpers
  class HttpClientHelper
  {
      HttpClient client;
      DateTime expiringSaS;
      (string hostname, string keyname, string key) config;
  
      public HttpClientHelper(string connectionString)
      {
          config = GetPartsFromConnectionString(connectionString);
          client = new HttpClient() { BaseAddress = new Uri($"https://{config.hostname}")};
          SetAuthorizationHeader();         
      }
  
      public HttpClient Client
      {
          get
          {          
              if (expiringSaS < DateTime.UtcNow.AddMinutes(-1))
              {
                 SetAuthorizationHeader();  
              }         
              return client;
          }
      }
  
      internal void SetAuthorizationHeader()
      {
          lock (client)
          {
              if (expiringSaS < DateTime.UtcNow.AddMinutes(-1)) 
              {
                  string sasToken = GetSASToken(config.hostname, config.key, config.keyname, 1);
                  if (client.DefaultRequestHeaders.Contains("Authorization"))
                      client.DefaultRequestHeaders.Remove("Authorization");
                  client.DefaultRequestHeaders.Add("Authorization", sasToken);
                  expiringSaS = DateTime.UtcNow.AddHours(1);
              }
          }
      }
  
      internal (string hostname, string keyname, string key) GetPartsFromConnectionString(string connectionString)
      {
          var parts = connectionString.Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries).Select(s => s.Split(new[] { '=' }, 2)).ToDictionary(x => x[0].Trim(), x => x[1].Trim());
          return (parts["HostName"] ?? "", parts["SharedAccessKeyName"] ?? "", parts["SharedAccessKey"] ?? "");
      }
  
      internal string GetSASToken(string resourceUri, string key, string keyName = null, uint hours = 24)
      {
          var expiry = GetExpiry(hours);
          string stringToSign = HttpUtility.UrlEncode(resourceUri) + "\n" + expiry;
          HMACSHA256 hmac = new HMACSHA256(Convert.FromBase64String(key));
  
          var signature = Convert.ToBase64String(hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign)));
          var sasToken = String.Format(CultureInfo.InvariantCulture, $"SharedAccessSignature sr={HttpUtility.UrlEncode(resourceUri)}&sig={HttpUtility.UrlEncode(signature)}&se={expiry}");
          if (!string.IsNullOrEmpty(keyName))
              sasToken += $"&skn={keyName}";
          return sasToken;
      }
  
      internal string GetExpiry(uint hours = 24)
      {
          TimeSpan sinceEpoch = DateTime.UtcNow - new DateTime(1970, 1, 1);
          return Convert.ToString((int)sinceEpoch.TotalSeconds + 3600 * hours);
      }
  }
  

  function.json：

  {
    "bindings": [
      {
        "name": "queueItem",
        "type": "serviceBusTrigger",
        "direction": "in",
        "queueName": "myQueue",
        "connection": "myConnectionString_SERVICEBUS"
      }
    ]
  }
  

  回复于 2024-04-29T14:45:49+08:00