This particular serialization problem took 2 midnight sessions to sort out. We had some untyped orchs published as webservices inside the service boundary and we were building a strong typed ASMX gateway as the service boundary. We used WSCF to generate the ASMX and used all the schemas that were inside the orchestrations so that we didnt have to maintain two different sets of messages. We then came across 2 problems, the first one more easily solved than the other. I’ll explain them below
(1)Duplicate namespaces: When you define a set of schemas in Biztalk, it is perfectly acceptable to define a common target namespace for example http://mycompany/schemas/services/customerservice and then to have different messages with specific root elements such as CreateCustomer, UpdateCustomer and so on. When biztalk recieves the message and validates them and works out the subscriptions, it adds the root element onto the target namespace making it http://mycompany/schemas/services/customerservice#CreateCustomer (note the # before the suffix) and this is enough for it to resolve most schemas. However, if you put all these Create, Update and Delete methods in your ASMX, then when you add a web reference, the .NET system crashes complaining of duplicate namespaces. Actually, the WSCF tool complained about duplicate namespaces even while creating the ASMX so we bypassed it and coded the ASMX ourselves (not realising it was right in complaining). This stumped us for a while, but it looks like this is default behavior in .NET and Biztalk has the ability to handle it but not the normal .NET framework which is fine. So we worked around it by changing the targetNamespace in all our schemas to have some extra phrases such as create, update and delete. Of course, if you put these kind of suffixes into the targetNamespace for biztalk its not a problem at all and it is then guaranteed to work in ordinary ASMX as well.
(2) Serialization and Precompilation: The second problem was much more involved. Once we finished revising the namespaces, we called the webservice only to get a nasty error message saying “File not found exception. System cannot find the file “xyz123”.dll (some arbitrary constantly changing name) . We tried setting all sorts of permissions everywhere and it didnt solve the problem. We narrowed it down to the serializer since ordinary webservice calls not involving complex types were working fine and since the webservice was writing to our debug log files we knew that the system wasnt even invoking the webservice. Finally we saw a post where someone recommended that we use Chris Sells’ XmlPrecompiler tool and the associated GUI built by Matthew Nolton. We then used the WSCF tool to generate a bunch of classes corresponding to the schema and checked them out. By this time i had also narrowed down the problem to a particular set of webmethods and one in particular where returning a void worked fine but returning a strong type caused the crash. Now the tool worked perfectly and crashed at the offending type. On close examination we found that by mistake, someone had created an array of arrays. (ie) we were returning an element called References and in that we needed unbounded elements named Reference with some attributes. It turned out that References had also been declared as unbounded. To add to this the namespaces were a bit muddled up and i read an article on MSDN saying that unqualified attributes in array types cause problems (or something to that effect). Anyway, i basically rewrote the schema to ensure all the elements were qualified correctly, corrected the ‘unbounded’ element and then it worked fine. There were also other schemas that dealt with arrays where the namespaces had to be reworked, but in the end it all worked fine.
This is a problem that one doesnt mind spending a couple of late nights working through eh? Who would have thought it would come down to finding a precompilation tool and sorting out the bug. So there it is… be very careful with schema definitions and arrays and use the precompiler tool as part of your quality checks. It will save a lot of tears and gain you some sleep as well.