Two WCF services with different contracts but same business objects

Question

For example I have two services hosted in IIS.

[ServiceContract]
public interface IDeviceService
{
    [OperationContract]
    DeviceCollection GetAllDevices(Customer customer);

}

[ServiceContract]
public interface IUserService
{
    [OperationContract]
    User Authenticate(string username, string password);

}

Both the User object that is returned from the Authenticate operation in the UserService and the DeviceCollection that is returned from the GetAllDevices operation in the DeviceService have a child object definition of Customer. Customer is a business object is in the same assembly as the User and Device objects.

My problem is on the client - when I call the device operation

userProxy.GetAllDevices(user.Customer);

The compiler complains with the following message:

Argument 1 - Cannot convert from UserService.Customer to DeviceService.Customer

I can connect to both services fine, it's the object definition of Customer that is the problem. I don't really want to put the Operations in the same service as they seem to live naturally in their own services. I guess what I'm asking is that how to other programmers deal with such a problem?

Cheers, Stuart

Answer 1

If you want to share a data contract across multiple services then you will have to compile the data contract in question into its own assembly and then distribute that assembly to the client.

Even though the type appears to be the same, it is in fact a two separate types and that is why you are seeing the error that you are seeing. Your only other choice (other than a separate, shared assembly) is to combine the two services into one so that they can share the data contract.

Answer 2

One option would be to use AutoMapper on the client to convert seamlessly from one type to another. As they have the same properties mappings would be straightforward.