xmlrpc: remote methods on attributes

Jeff Bauer jbauer at rubic.com
Thu Apr 27 21:40:19 CEST 2000


Hi all. I've been playing around with PythonWare's 
xmlrpclib module.

It's pretty neat, but I want to remotely invoke methods 
on attributes.  After diddling around and trying to
fool the library, I opted for a more straightforward
approach: a RemoteMethod mixin.

### WARNING: Code for discussion purposes only. ###
from types import FunctionType

class RemoteMethod:
    def __init__(self):
        self.__methods__ = {}
        for n, m in get_members(self.__class__).items():
            if n[:2] != '__' and \
               type(m) is FunctionType:
                self.__methods__[n] = m
    def __rcall__(self, method, params):
        if self.__methods__.has_key(method):
            return apply(self.__methods__[method], (self,)+params)
        try:
            pos = string.index(method, '.')
        except ValueError:
            pass
        else:
            head = method[:pos]
            tail = method[pos+1:]
            if hasattr(self, head):
                return self.__dict__[head].__rcall__(tail, params)
        return None

def get_members(_class, members=None):
    if members is None:
        members = {}
    for k in _class.__bases__:
        get_members(k, members)
    for n, m in vars(_class).items():
        if not members.has_key(n):
            members[n] = m
    return members

########################################################

An example of how an xmlrpc server could be implemented:

class Blarg(RemoteMethod):
    def __init__(self):
        apply(RemoteMethod.__init__, (self,))
    def blarg_method(self, x):
        return "blarg_method(%s)" % x

class Server(RemoteMethod, xmlrpc_handler):
    def __init__(self):
        apply(RemoteMethod.__init__, (self,))
        self.blarg = Blarg()

########################################################

In a separate module, the server is remotely invoked.
I map 'call' to '__rcall__' in the top level connection
object, derived from xmlrpclib.

    server = Server("http://yadda-yadda")
    print server.blarg.blarg_method("Aieee!")

########################################################

I'd be interested in anyone's comments about this
approach, especially from other xmlrpc users.  Thanks.

Jeff Bauer
Rubicon Research




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