Azure ServiceBus from Xamarin Forms PCL

Question

How is the messaging through the Azure Service Bus from the Xamarin Forms PCL ... is there an SDK, library or plugin? If there is a manual broker method, I assume that this can be done using the HttpClient and REST API ...

Answer 1

Finally, I have a working method for sending a message to the Azure Service Bus queue from the Xamarin PCL! The way to do this is through the HttpClient.

Gotchas who made the decision elusive:

• The nuget package for Microsoft.ServiceBus.Messaging will happily install, but is not subject to, the portable class.

• WebClient examples abound, but there is no web client available in PCL!

• PCL HMACSHA256 . PCLCrypto nuget.
• Content-Type: application/atom + xml; type = entry; charset = utf-8 BrokerProerties. !

• : BaseServiceBusAddress + queue + "/messages"

  public const string ServiceBusNamespace = [YOUR SERVICEBUS NAMESPACE];
  
  public const string BaseServiceBusAddress = "https://" + ServiceBusNamespace + ".servicebus.windows.net/";
  
  /// <summary>
  /// The get shared access signature token.
  /// </summary>
  /// <param name="sasKeyName">
  /// The shared access signature key name.
  /// </param>
  /// <param name="sasKeyValue">
  /// The shared access signature key value.
  /// </param>
  /// <returns>
  /// The <see cref="string"/>.
  /// </returns>
  public static string GetSasToken(string sasKeyName, string sasKeyValue)
  {
      var expiry = GetExpiry();
      var stringToSign = WebUtility.UrlEncode(BaseServiceBusAddress ) + "\n" + expiry;
  
      var algorithm = WinRTCrypto.MacAlgorithmProvider.OpenAlgorithm(MacAlgorithm.HmacSha256);
      var hasher = algorithm.CreateHash(Encoding.UTF8.GetBytes(sasKeyValue));
      hasher.Append(Encoding.UTF8.GetBytes(stringToSign));
      var mac = hasher.GetValueAndReset();
      var signature = Convert.ToBase64String(mac);
  
      var sasToken = string.Format(CultureInfo.InvariantCulture, "SharedAccessSignature sr={0}&sig={1}&se={2}&skn={3}", WebUtility.UrlEncode(baseAddress), WebUtility.UrlEncode(signature), expiry, sasKeyName);
      return sasToken;
  }
  
  /// <summary>
  /// Posts an order data transfer object to queue.
  /// </summary>
  /// <param name="orderDto">
  /// The order data transfer object.
  /// </param>
  /// <param name="serviceBusNamespace">
  /// The service bus namespace.
  /// </param>
  /// <param name="sasKeyName">
  /// The shared access signature key name.
  /// </param>
  /// <param name="sasKey">
  /// The shared access signature key.
  /// </param>
  /// <param name="queue">
  /// The queue.
  /// </param>
  /// <returns>
  /// The <see cref="Task"/>.
  /// </returns>
  public static async Task<HttpResponseMessage> PostOrderDtoToQueue(OrderDto orderDto, string serviceBusNamespace, string sasKeyName, string sasKey, string queue)
  {
      using (var client = new HttpClient())
      {
          client.BaseAddress = new Uri(BaseServiceBusAddress);
          client.DefaultRequestHeaders.Accept.Clear();
  
          var token = GetSasToken(sasKeyName, sasKey);
          client.DefaultRequestHeaders.Add("Authorization", token);
  
          HttpContent content = new StringContent(JsonConvert.SerializeObject(orderDto), Encoding.UTF8);
          content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
  
          var path = BaseServiceBusAddress + queue + "/messages";
  
          return await client.PostAsync(path, content);
      }
  }
  
  /// <summary>
  ///     Gets the expiry for a shared access signature token
  /// </summary>
  /// <returns>
  ///     The <see cref="string" /> expiry.
  /// </returns>
  private static string GetExpiry()
  {
      var sinceEpoch = DateTime.UtcNow - new DateTime(1970, 1, 1);
      return Convert.ToString((int)sinceEpoch.TotalSeconds + 3600);
  }
  

  }