Custom SOAP Headers

Wow, it has been awhile since I've been able to post any new content on this blog. It has been a very busy summer and I have to say that there are a few great projects that I've been working on and hope to release to the wild in a few weeks/months time.

In the meantime, I thought I'd post some code samples illustrating some of the new features of the WCF connector in the upcoming Everest 1.0.2 release (a minor update and bug-fix release). If you've ever had to use the WcfClientConnector or WcfServerConnector, you'll know that dealing with SOAP headers was … well… cumbersome. It required setting some odd properties and wasn't really thread safe. This has been addressed in the 1.0.1 release.

For this example, I'll show you how to read/write the WS-Addressing headers in a received message from the WCF connectors. First, to access the SOAP headers from a message received from a WcfServerConnector, you can simply access the Headers property on the WcfReceiveResult. The following code is written in the MessageAvailable event handler for a WcfServerConnector:

static void conn_MessageAvailable(object sender, MARC.Everest.Connectors.UnsolicitedDataEventArgs e)
{
     // Get the sending connector that raised the event
     var connector = sender as  WcfServerConnector;
     if (connector == null)
          throw new ArgumentException("Must be called from a WcfServerConnector", "sender");
     // Receive the message
     var receiveResult = connector.Receive() as WcfReceiveResult;

Pretty standard Everest stuff, next we'll emit the value of the WS-Addressing headers:

if (receiveResult.Headers != null){

     Console.WriteLine(receiveResult.Headers.To);
     Console.WriteLine(receiveResult.Headers.Action);
}

We can access the Headers array just like any other WCF Header, this applies to constructing the response as well. To construct the response, populate the ResponseHeaders on the receiveResult prior to call "Send()" on the server connector.

receiveResult.ResponseHeaders = new System.ServiceModel.Channels.MessageHeaders
(receiveResult.Headers.MessageVersion);
receiveResult.ResponseHeaders.Add(MessageHeader.CreateHeader("myHeader", "urn:my-ns:com", "Value"));
connector.Send(new MCCI_IN000002CA(), receiveResult);

This code will return the following soap header:

<tns:myHeader xmlns:tns="urn:my-ns:com">Value</tns:myHeader>

More complex headers can be added the same way you would add standard System.ServiceModel.Channel.MessageHeader objects. It is also possible to send message headers using the overridden Send() method on the WcfClientConnector:

var conn = new WcfClientConnector();
// trimmed
MessageHeaders messageHeaders = new System.ServiceModel.Channels.MessageHeaders(MessageVersion.Soap12);messageHeaders.Add(MessageHeader.CreateHeader("myHeader", "urn:my-ns:com", "Value"));
conn.Send(instance, messageHeaders);

As I said, this enhancement will be available in the 1.0.2 release of Everest, or is available in the 1.0 branch of the Everest SVN server (or the trunk if you're feeling adventurous and want to try Everest 1.2 features out as well).