[Zope] xmlrpc calls require string results?

[Toby Dickenson]

> I'm using xmlrpclib from a standalone Python script to post 
> articles to
> Squishdot.  It seems that calls to methods that return 
> strings work fine,
> while calls to other methods fail with tracebacks like the following:
> 
> Traceback (innermost last):
>   File "./postToControlCom.py", line 77, in ?
>     postMessage(msg)
>   File "./postToControlCom.py", line 68, in postMessage
>     summary, subject, "Automation List")
>   File "./xmlrpclib.py", line 547, in __call__
>     return self.__send(self.__name, args)
>   File "./xmlrpclib.py", line 630, in __request
>     request
>   File "./xmlrpclib.py", line 582, in request
>     headers
> xmlrpclib.ProtocolError: <ProtocolError for 
> silver.control.com/zope/: 500
> Internal Server Error>
> 

.....

>    # if a method called by it doesn't return a string.
>     # This is bogus, but:
>     return 'Done'
> 
> BTW: all of this appears to me to be true whether or not Squishdot is
> involved -- I have tested with target methods that are not part of it.
> 
> What am I doing wrong here?

Obviously xmlrpclib needs to be able to marshal the return value back to the
caller. The xmlrpc spec has no equivalent of the 'None' that results from a
returnless function in python, hence the error.

The return values does not have to be a string; just something that xmlrpc
understands.