WCF（de）序列化在debug / Visual Studio和IIS下的行为不同

Question

I have a WCF service I am hosting, where one of the methods has an element of type xs:AnyType. In my code, I serialize the xs:Any as XmlNode

In visual studio (iis express) my messages come through perfectly, with the XML loaded into the XmlNode property. When I deploy to IIS and send THE EXACT SAME MESSAGE, I get a < as the entire content of the property.

There is a related issue I ran into previously, where under Visual Studio the real type of the hydrated property is XmlElement, but in IIS it is coming through as XmlText (which I why I chose XmlNode, a common ancestor) See that previous issue here WCF message with xs:anytype causing serialization problems

It seems likely that these two issues are related, but why is the application using different serialization logic under visual studio than in IIS?

Answer 1

After burning an MSDN support ticket we have found the root cause of both issues. It was not IIS vs IIS express related, the content of the messages was subtly different.

The xsd:anyType allows for arbitrary XML to be sent. In this case, the Java application is sending HtmlEncoded xml as the payload for that element. rather than puking on this content and throwing a serialization error, WCF accepts it, and hydrates it as XmlText instead of XmlElement. However, after hydration, the full payload is not there, only a <

Making this issue confusing is that all debug windows, the WCF traces, etc all "fixed" the htmlEncoded content to display as valid XML. Therefore, when I copied the message out of the WCF Trace, and ran it manually from SoapUI to try and reproduce, the behavior changed!

I'm pushing back on the customer to fix the payload in the message they send, but if that is not possible, using a IDispatchMessageInspector.AfterReceiveRequest method will be able to convert the payload and send it through correctly.