I was trying to port some working code that calls the Amazon
E-Commerce web services via SOAP calls to SOAP4R tonight. After quite
a bit of head-scratching, I realized that the default values for the
parameters passed to the constructors of the SOAP request message
types are nil. This causes the SOAP serializer to barf something
awful, and the stack trace was, um somewhat less than helpful :)

Instead of simply constructing an object like ItemLookupRequest and
omitting the values to the constructor, you must specify empty strings
for the parameters that you don't care about. If you do this,
everything works just fine.

I wanted to add this message to the archives since this might help
someone else going down this path in the future.

Also, is the behavior of wsdl2ruby correct in specifying nil for the
default values of parameters that you don't explicitly pass to the
constructor? Or is it a bug in the SOAP serializer?

Thanks
-John
http://www.iunknown.com