ASMX to WCF SOAP Headers

Question

Hi,

I've written a large asmx web service and now i want to port it to WCF service. What is the easiest way to do that by having in mind that i have applied [SoapHeader] attribute to almost every web method in the asmx service. This attribute always points to one SoapHeader inheritor class. Can I add some attribute ( like SoapHeaderAttribute in asmx ) along with the OperationContractAttribute to add this SOAP header. Or I have to create a wrapper classes for all types I use in order to add the header by using MeassgeHeader.

Thanks in advance,

Kostadin

Answer 1

As you say, you could use the [MessageContract] model and use [MessageHeader] to do this.  Another possibility is to just programmatically add and find headers, as in the sample code below.  I have bolded the parts where the client adds a header to the outbound message and the server reads it off the inbound message. 

using System;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;
using System.ServiceModel.Channels;

[ServiceContract]
public interface IMyContract
{
    [OperationContract]
    string echo(string s);
}

public class MyService : IMyContract
{
    public string echo(string s)
    {
        // fyi, here is what the wire message looked like
        Console.WriteLine(OperationContext.Current.RequestContext.RequestMessage.ToString());
        // find the header we are interested in (lookup by name/namespace)
        int index = OperationContext.Current.IncomingMessageHeaders.FindHeader("foo", "");
        string h = OperationContext.Current.IncomingMessageHeaders.GetHeader<string>(index);
        Console.WriteLine(h);

        return s;
    }
}

public class Repro
{
    public static void Main()
    {
        Uri address = new Uri("http://localhost:8004/Service");
        Binding binding = new BasicHttpBinding();

        ServiceHost service = new ServiceHost(typeof(MyService), address);
        service.AddServiceEndpoint(typeof(IMyContract), binding, address);
        service.Open();

        ChannelFactory<IMyContract> cf = new ChannelFactory<IMyContract>(binding, new EndpointAddress(address));
        IMyContract proxy = cf.CreateChannel();
        using (OperationContextScope ocs = new OperationContextScope((IContextChannel)proxy))
        {
            // add header with name "foo", namespace "", value "val" to this operation call
            OperationContext.Current.OutgoingMessageHeaders.Add(MessageHeader.CreateHeader("foo", "", "val"));
            Console.WriteLine(proxy.echo("Hello World"));
        }
        ((IClientChannel)proxy).Close();
        service.Close();
        Console.WriteLine("Done, press a key");
        Console.ReadKey();
    }
}

 

Answer 2

Thanks Brian,

This solution is fine, but I wish that the soap header which has always the same structure for all messages to be described in the WSDL for all this messages. Is [MessageContract] the only solution for that scenario and can I somehow add [MessageHeader] to the method so it won't be necessary to create new MessgaeContract types for all methods.

So if I have this:

[OperationContract]

ReturnType methodOne( type1 param1, type2 param2, ..... , typeN paramN )

Can i add some attribute to this signature to tell that the incomming ant outgoing messages are decorated with some header - "MySoapHeader"

Or I have to do the following:

[OperationContract]

OutgoingMessage methodOne( IncommingMessage incommingMessage )

 

[MessageContract]

public class IncommingMessage

{

[MessageHeader]

MySoapHeader mySoapHeader;

[MessageBodyMember]

type1 param1;

.....

[MessageBodyMember]

typeN paramN;

}

[MessageContract]

public class OutgoingMessage

{

[MessageHeader]

MySoapHeader mySoapHeader;

[MessageBodyMember]

ReturnType returnParam;

}

Answer 3

There is one problem with the MessageContract approach. There are asp.net clients using the service I am porting to WCF one. And these clients must remain unchanged when consuming the new WCF service. But when returning a MessageContract ( header + method return value ) from a method the asp.net clients generate proxy method returning void ( not the actual return type specified in the MessageContract ) and having the retrurn value as out parameter + one more out parameter of type bool starting with the same name as the first one and ending with "Specified".

So instead of generating the proper one:

returnType methodOne( ... )

it generates something like:

void methdOne( out returnType returnValue, out bool returnValueSpecified, ... )

Is there any way to make it generate the first one?

 

Thanks

Answer 4

Try this:
...

[MessageContract (IsWrapped = false)]

public class OutgoingMessage

{

[MessageHeader]

MySoapHeader mySoapHeader;

[MessageBodyMember]

ReturnType returnParam;

}

...

Bye
Marco

Answer 5

This might help:

http://www.codeplex.com/WCFExtras