with azure brokeredmessage get the body without knowing the type

Question

When you are using the brokered message in the Azure Service Bus, you can retrieve the body of the message with the call .GetBody. The code is simple:

var msg = subscription.Receive();
MyPayload payload = msg.GetBody<MyPayload>();

However, is there a way to retrieve the Body without explicitly knowing the class of the body object?

var msg = subscription.Receive();
Type bodyType = Type.GetType( msg.ContentType);

var payload = msg.GetBody<bodyType>();

score 81 · Answer 1 · edited Feb 11 '16 at 17:42

81

If the intent is to only grab the message body regardless of the content you can get it as a stream.

Stream stream = message.GetBody<Stream>();
StreamReader reader = new StreamReader(stream);
string s = reader.ReadToEnd();

edited Feb 11 '16 at 17:42

Nikolai Samteladze

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answered Mar 15 '13 at 21:05

ckross01

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Nice tip! This should have been part of the MSDN documentation :) – Hector Correa Nov 08 '13 at 16:51
1

This is also really useful for inter-op with Node where you might want to send around JSON in the body of a message – Peter M Oct 26 '15 at 21:28
1

which gives extra string char with my output like `@string3http://schemas.microsoft.com/2003/10/Serialization/�h {"MyID":"121"}` – Neo Sep 03 '18 at 07:57
@Neo yes, that's right, I get this additional text as soon as I do GetBody(). Is there a clean way to remove this? Is this something to do with encoding? – Vinod Jun 09 '20 at 13:35
Ok, someone looking to get rid of it, I refer to the following answer, worked like a charm :-) https://stackoverflow.com/a/47429841/419556 – Vinod Jun 09 '20 at 17:53
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Since this is using the `Stream` classes... should `using` be used? Or does this not require disposing? – MBender Nov 27 '20 at 09:06

score 31 · Accepted Answer · answered Mar 27 '13 at 16:44

31

Here is the complete code to deserialize from the brokeredmessage:

public T GetBody<T>(BrokeredMessage brokeredMessage)
{
  var ct = brokeredMessage.ContentType;
  Type bodyType = Type.GetType(ct, true);

  var stream = brokeredMessage.GetBody<Stream>();
  DataContractSerializer serializer = new DataContractSerializer(bodyType);
  XmlDictionaryReader reader = XmlDictionaryReader.CreateBinaryReader(stream, XmlDictionaryReaderQuotas.Max);
  object deserializedBody = serializer.ReadObject(reader);
  T msgBase = (T)deserializedBody;
  return msgBase;
}

answered Mar 27 '13 at 16:44

yamspog

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This depends on brokeredMessage.ContentType. If we just send string this property may or may not be set. Are there any way to identify its a simple string,stream or class type? – Joy George Kunjikkuru Jun 25 '13 at 14:03
1

This answer helped solve serialization errors using GetBody() on a WebWorkerRole in Azure trying to access the body of a brokeredmessage. Thanks. – TombMedia Jul 02 '13 at 09:41
@Joymon Not sure if it's good practice, but you can set the ContentType when you send the message: var message = new BrokeredMessage(request); message.ContentType = request.GetType().Name; – Dunc May 06 '15 at 18:34
It's possible simplify with this: var bodyType = System.Type.GetType("System.String"); – Fernando JS Jan 16 '18 at 18:51

score 6 · Answer 3 · answered Nov 11 '13 at 18:58

In sample before ContentType utilized to detect body type. I believe ContentType should be set by sender. I do similar logic, I set one of message properties to type of object on sender side and call GetBody<>() on receiver with type retrived from message property. like this:

public void SendData(object payloadData)
    {
        if (payloadData == null) return;

        var queueClient = QueueClient.CreateFromConnectionString(ConnectionString, _queueName);

        var brokeredMessage = new BrokeredMessage(payloadData);
        brokeredMessage.Properties["messageType"] = payloadData.GetType().AssemblyQualifiedName;
        queueClient.Send(brokeredMessage);
    }

Message property "messageType" has full name of type.

On receiving side I do like this:

 var messageBodyType = Type.GetType(receivedMessage.Properties["messageType"].ToString());
                if (messageBodyType == null)
                {
                    //Should never get here as a messagebodytype should
                    //always be set BEFORE putting the message on the queue
                    Trace.TraceError("Message does not have a messagebodytype" +
                                     " specified, message {0}", receivedMessage.MessageId);
                    receivedMessage.DeadLetter();
                }


                //read body only if event handler hooked
                    var method = typeof(BrokeredMessage).GetMethod("GetBody", new Type[] { });
                    var generic = method.MakeGenericMethod(messageBodyType);
                    try
                    {
                        var messageBody = generic.Invoke(receivedMessage, null);
                         DoSomethingWithYourData();
                        receivedMessage.Complete();
                    }
                    catch (Exception e)
                    {
                        Debug.Write("Can not handle message. Abandoning.");
                        receivedMessage.Abandon();
                    }
                }

Thank you sir! This is exactly the solution I was looking for! — Casey Crookston, Jan 05 '16 at 15:04

with azure brokeredmessage get the body without knowing the type

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