Twisted XML-RPC error

I get an exception on both client and server side when I run the first example at http://buildbot.twistedmatrix.com/builds/sphinx-html/291-15849/projects/web/howto/xmlrpc.html. The server code I used is below:

from twisted.web import xmlrpc, server

class Example(xmlrpc.XMLRPC):
    """An example object to be published."""

    def xmlrpc_echo(self, 开发者_StackOverflow中文版x):
        """
        Return all passed args.
        """
        return x

    def xmlrpc_add(self, a, b):
        """
        Return sum of arguments.
        """
        return a + b

    def xmlrpc_fault(self):
        """
        Raise a Fault indicating that the procedure should not be used.
        """
        raise xmlrpc.Fault(123, "The fault procedure is faulty.")

if __name__ == '__main__':
    from twisted.internet import reactor
    r = Example()
    reactor.listenTCP(7080, server.Site(r))
    reactor.run()

Client side is below:

import xmlrpclib

s = xmlrpclib.Server('http://localhost:7080/')
print s.echo('Hello world')

The server side exception is:

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/twisted/web/xmlrpc.py", line 150, in render_POST
    d.addCallback(self._cbRender, request, responseFailed)
  File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 260, in addCallback
    callbackKeywords=kw)
  File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 249, in addCallbacks
    self._runCallbacks()
  File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 441, in _runCallbacks
    self.result = callback(self.result, *args, **kw)
--- <exception caught here> ---
  File "/usr/lib/python2.6/dist-packages/twisted/web/xmlrpc.py", line 170, in _cbRender
    allow_none=self.allowNone)
exceptions.TypeError: dumps() got an unexpected keyword argument 'allow_none'

Client side exception is:

Traceback (most recent call last):
  File "./client.py", line 6, in <module>
    print s.echo('Hello world')
  File "/usr/local/lib/python2.6/dist-packages/xmlrpclib-1.0.1-py2.6.egg/xmlrpclib.py", line 986, in __call__
    return self.__send(self.__name, args)
  File "/usr/local/lib/python2.6/dist-packages/xmlrpclib-1.0.1-py2.6.egg/xmlrpclib.py", line 1239, in __request
    verbose=self.__verbose
  File "/usr/local/lib/python2.6/dist-packages/xmlrpclib-1.0.1-py2.6.egg/xmlrpclib.py", line 1037, in request
    return self._parse_response(h.getfile(), sock)
  File "/usr/local/lib/python2.6/dist-packages/xmlrpclib-1.0.1-py2.6.egg/xmlrpclib.py", line 1136, in _parse_response
    p.close()
  File "/usr/local/lib/python2.6/dist-packages/xmlrpclib-1.0.1-py2.6.egg/xmlrpclib.py", line 508, in close
    self._parser.Parse("", 1) # end of data
xml.parsers.expat.ExpatError: no element found: line 1, column 0

Looks like you have an old version of xmlrpclib?

What version of python are you using? Where is the xmlrpclib coming from that your xmlrpc server is using, and what version is it?

$ python -v
>>> import xmlrpclib
# /usr/lib/python2.6/xmlrpclib.pyc matches /usr/lib/python2.6/xmlrpclib.py
>>> xmlrpclib.__version__
'1.0.1'
>>> xmlrpclib.dumps((None,), allow_none=True)
'<params>\n<param>\n<value><nil/></value></param>\n</params>\n

i.e. this works for me. Perhaps you are somehow using an old version of xmlrpclib?