ActiveMQ - deserialize an ActiveMQBytesMessage message

Question

In my job, I work with an application developped partly in c++ and C#. The C++ code is responsible to manage activeMQ (send, receive message).

I've developped an application to monitor the messages sent in the topic by subscribing myself with my C# application.

So when a message is sent to a topic, my application manage to handle the message, but the message is serialized in ActiveMQBytesMessage.

How can I deserialize this object ?

public void OnMessage(IMessage message)
    {
        if (message != null)
        {
            var content = (message as ActiveMQBytesMessage).Content; // This is a byte[], I tried to deserialize using BinaryFormatter but it throws an exception, I can't write it here because I'm at home.
        }
    }

I just noticed that ActiveMQBytesMessage inherits IBytesMessage from namespace Apache.NMS, but I see nothing which helps me to deserialize the message.

I use the last version of ActiveMQ with NMS

[NB] The goal of my C# application is to simply monitor what's happening inside an ActiveMQ channel. That's why I need to deserialize the ActiveMQBytesMessage so I can display the name of the object and its content in a gridview.

[Added more information]

Here's what i tried to deserialize.

var memoryStream = new MemoryStream((message as ActiveMQBytesMessage).Content);
var binaryFormatter = new BinaryFormatter();

memoryStream.Position = 0;

var deserializedMessage = binaryFormatter.Deserialize(memoryStream);

And I get this error when it deserializes:

The input stream is not a valid binary format. The starting contents (in bytes) are: 00-00-00-00-00-00-4F-8C-00-00-00-09-00-00-00-00-54 ...

You need to provide more context. What are you serializing and from where. Naturally something sent from C++ isn't going to just deserialize into a C# object, which is what your question makes it sound like you are trying to do. A more detailed breakdown of your problem would help you get a better answer. — Tim Bish, May 08 '12 at 18:02
Hi Tim, the serialized object can be anything. What I've seen so far, is that most of the time the C++ (managed) send a C# object which I can reference in my project to deserialize. Is there anything else I can provide to clarify the context ? Feel free to ask me please. — John, May 08 '12 at 18:52
Have you tried `var deserializedMessage = binaryFormatter.Deserialize(new RemotingSurrogateSelector(), memoryStream);`? — david.s, May 14 '12 at 14:46
Hi david.s, there're an error in your instruction. Deserialize method doesn't take an object of type RemoteSurrogateSelector() — John, May 14 '12 at 15:10

score 1 · Accepted Answer · edited May 23 '17 at 11:48

(I am making a few assumptions here, since you didn't specify certain details.) The BinaryFormatter you are attempting to use will only work for .NET objects, not for C++ objects. Most likely, these objects have not been encoded in a platform neutral way, and are in a C++ format specific to that particular compiler and platform. Therefore, it is up to you to parse the binary code directly to determine what object is encoded, and then to manually decode the data. If these are non-trivial objects, this will be a difficult task. If at all possible, try to get the original application to encode the objects into a platform neutral format that can be easily parsed and instantiated in C#. (I prefer using a TextMessage and XML encoding.) It won't be as efficient as the direct C++ to C++ encoding/decoding that is apparently going on right now, but it will allow external monitoring of the message stream. When I do this, I put the full typename (including namespace) of the object in the NMSType header property. This then tells me the internal structure of message content, and I can instantiate the correct object for parsing the data out of the message.

If all of that doesn't help, or the assumption is wrong and you are using Managed C++, perhaps this question/answer will help you: What serialization method is used for an ActiveMQ NMS C# object message?

ActiveMQ - deserialize an ActiveMQBytesMessage message

1 Answers1