Twisted XML-RPC错误

Question

我在运行这个例子时，客户端和服务器端都出现了异常，链接是 http://buildbot.twistedmatrix.com/builds/sphinx-html/291-15849/projects/web/howto/xmlrpc.html。我使用的服务器代码如下：

from twisted.web import xmlrpc, server

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

    def xmlrpc_echo(self, 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()

客户端代码如下：

import xmlrpclib

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

服务器端的异常信息是：

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'

客户端的异常信息是：

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

Answer 1

看起来你用的是一个旧版的xmlrpclib？

你现在用的是什么版本的Python？你的xmlrpc服务器用的xmlrpclib是从哪里来的，版本是什么？

$ 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

也就是说，这个对我来说是有效的。也许你不小心用了一个旧版的xmlrpclib？