I'm implementing a client-server application, and am looking into various ways to serialize and transmit data. I began working with Xml Serializers, which worked rather well, but generate data slowly, and make large objects, especially when they need to be sent over the net. So I started looking into Protobuf, and protobuf-net.

My problem lies in the fact that protobuf doesn't sent type information with it. With Xml Serializers, I was able to build a wrapper which would send and receive any various (serializable) object over the same stream, since object serialized into Xml contain the type name of the object.

ObjectSocket socket = new ObjectSocket();
socket.AddTypeHandler(typeof(string));  // Tells the socket the types
socket.AddTypeHandler(typeof(int));     // of objects we will want
socket.AddTypeHandler(typeof(bool));    // to send and receive.
socket.AddTypeHandler(typeof(Person));  // When it gets data, it looks for
socket.AddTypeHandler(typeof(Address)); // these types in the Xml, then uses
                                        // the appropriate serializer.

socket.Connect(_host, _port);
socket.Send(new Person() { ... });
socket.Send(new Address() { ... });
...
Object o = socket.Read();
Type oType = o.GetType();

if (oType == typeof(Person))
    HandlePerson(o as Person);
else if (oType == typeof(Address))
    HandleAddress(o as Address);
...

I've considered a few solutions to this, including creating a master "state" type class, which is the only type of object sent over my socket. This moves away from the functionality I've worked out with Xml Serializers, though, so I'd like to avoid that direction.

The second option would be to wrap protobuf objects in some type of wrapper, which defines the type of object. (This wrapper would also include information such as packet ID, and destination.) It seems silly to use protobuf-net to serialize an object, then stick that stream between Xml tags, but I've considered it. Is there an easy way to get this functionality out of protobuf or protobuf-net?

I've come up with a third solution, and posted it below, but if you have a better one, please post it too!