NServiceBus allows control over deserialization? - nservicebus

Question

I am trying to integrate a legacy application with NServiceBus by wrapping XML exports from the application with a NServiceBus "wrapper" which basically strips out namespaces and adds the envelope and NSB namespace.
I have the basic solution working but only if the root element of the XML export exactly matches the NServiceBus message type name.
For example if the xml is:
<?xml version="1.0"?>
<Messages xmlns="http://tempuri.net/MyMessagesNamespace">
<!-- Note: the "V1" -->
<PolicyEndorsedV1>
...
</PolicyEndorsedV1>
</Messages>
then my handler code can happily deserialize:
namespace MyMessagesNamespace
{
public class PolicyEndorsedV1Handler : IHandleMessages<PolicyEndorsedV1>
{
public void Handle(PolicyEndorsedV1 message)
{
// All work fine!
...
}
}
}
However, if the export XML is
<?xml version="1.0"?>
<Messages xmlns="http://tempuri.net/MyMessagesNamespace">
<!-- Note: the "V1" has been removed -->
<PolicyEndorsed>
...
</PolicyEndorsed>
</Messages>
this will not be deserialised. NServiceBus tells me System.TypeLoadException: Could not handle type 'Beazley.Messages.Risks.Events.PolicyEndorsed', which is understandable as the only information it's got to go on is the name of the root node on the incoming xml.
I have tried to control the deserialization behaviour by adding some of the .Net Serialization attributes to my message definition:
[XmlRoot(ElementName = "PolicyEndorsed", Namespace = "", IsNullable = false)]
public partial class PolicyEndorsedV1
{
...
}
but this is ignored because NServiceBus uses it's own serializer (called XmlMessageSerializer) and not .Net's own XmlSerializer.
So does anyone know how I can do this? I think it would be nice to have the option to decouple the Xml names with their NSB messaging counterparts.
Many thanks

Answer 1

Does PolicyEndorsedV1 inherit from PolicyEndorsed?
If so, use IHandleMessages<PolicyEndorsed>, and PolicyEndorsedV1Handler will handle both types of objects.
For example:
public class PolicyEndorsedV1Handler : IHandleMessages<PolicyEndorsed>
{
public void Handle(PolicyEndorsed message)
{
// Handles both PolicyEndorsed and PolicyEndorsedV1 messages
}
}