BrokerProperties REST header values not showing up in .NET client code

I'm writing two small pieces of C# code. The first is for a client-side Portable Class Library. All it does is send messages to an Azure Service Bus topic via the Azure Service Bus REST API, using HttpClient.

I populate the BrokerProperties header on the REST call with valid JSON, and I expect that on the server side, when I receive the message through a subscription, that I'll get my instance of BrokeredMessage.Properties populated with the values I sent from the client.

The one problem I've had on this side is that the documentation says to set Content-Type to application/atom+xml;type=entry;charset=utf-8, but even when I do I get application/json; charset=utf-8, so I'm just using application/json.

With that aside, as far as I can tell, this does what it's supposed to do. It creates the client and the request message, sets the headers, and sends the message. I get a 201 Created every time. Here's all of it:

    private async static void SendServiceBusMessage(Command command)
    {
        // Create the HttpClient and HttpRequestMessage objects
        HttpClient client = new HttpClient();
        HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, topicUri);

        // Add the authorization header (CreateAuthToken does the SHA256 stuff)
        request.Headers.Add("Authorization", CreateAuthToken(topicUri, authSasKeyName, authSasKey));

        // Add the content (command is a normal POCO)
        // I've tried application/atom+xml;type=entry;charset=utf-8, always see application/json in the request
        request.Content = new StringContent(JsonConvert.SerializeObject(command), Encoding.UTF8, "application/json");

        // Add the command name and SessionId as BrokeredMessage properties
        var brokeredMessageProperties = new Dictionary<string, string>();
        brokeredMessageProperties.Add("CommandName", command.GetType().Name);
        brokeredMessageProperties.Add("SessionId", Guid.NewGuid().ToString());

        // Add the BrokerProperties header to the request
        request.Content.Headers.Add("BrokerProperties", JsonConvert.SerializeObject(brokeredMessageProperties));

        // I've also tried adding it directly to the request, nothing seems different
        // request.Headers.Add("BrokerProperties", JsonConvert.SerializeObject(brokeredMessageProperties));

        // Send it
        var response = await client.SendAsync(request);
        if (!response.IsSuccessStatusCode)
        {
            // Do some error-handling
        }
    }

and here's an example of the HTTP request it sends. Compare it to the example at the bottom of Send Message documentation... aside from the Content-Type, it looks (functionally) identical to me.

  POST http://ift.tt/1Ictn6J HTTP/1.1
  Authorization: SharedAccessSignature sr=https%3A%2F%2Fmyawesomesbnamespace.servicebus.windows.net%2Fcommands%2Fmessages&sig=SomeValidAuthStuffHere
  Content-Type: application/json; charset=utf-8
  BrokerProperties: {"CommandName":"CreateJob_V1","SessionId":"94932660-54e9-4867-a020-883a9bb79fa1"}
  Host: myawesomesbnamespace.servicebus.windows.net
  Content-Length: 133
  Expect: 100-continue
  Connection: Keep-Alive

  {"JobId":"6b76e7e6-9499-4809-b762-54c03856d5a3","Name":"Awesome New Job Name","CorrelationId":"47fc77d9-9470-4d65-aa7d-690b65a7dc4f"}

However, when I receive the message on the server, the .Properties are empty. This is annoying.

The server code looks like this. It just gets a batch of messages and does a foreach loop.

    private async Task ProcessCommandMessages()
    {
        List<BrokeredMessage> commandMessages = (await commandsSubscriptionClient.ReceiveBatchAsync(serviceBusMessageBatchSize, TimeSpan.FromMilliseconds(waitTime_ms))).ToList();

        foreach (BrokeredMessage commandMessage in commandMessages)
        {
            // commandMessage.Properties should have CommandName and SessionId,
            // like I sent from the client, but it's empty
            // that's not good
            if (commandMessage.Properties.ContainsKey("CommandName"))
            {
                string commandName = commandMessage.Properties["CommandName"] as string;
                // Do some stuff
            }
            else
            {
                // This is bad, log an error
            }
        }
    }

So, I'm a bit stuck. Can anyone spot something I'm doing wrong here? Maybe it's the Content-Type problem and there's a way around it?

Thanks!

Scott

Seattle, WA, USA