mirroring object attributes using xml-rpc

[sashang]

Hi

Say I have a class like the following

class Test:
i = 1

def geti(self):
return self.i

And I use it in an xml-rpc server like this:

t = Test()
s.register_instance(t)

Then the client code can get the value of i like this:
c = xmlrpclib.ServerProxy("address")
c.geti()

but why can't I get the value of i like this?

c.i

How can I implement such behaviour? Moreover, if there were more member
objects in the class Test, how can tell the client 1) that these
attributes exist and 2) how can I use them from the client side without
having to resort to defining a function get_xxx() in the server class?

 

[sashang]

Just to make things clearer the problem I have is if I do this:

c = xmlrpclib.ServerProxy("http://somewhere")
c.i

I get this error:

<Fault 1: "exceptions.TypeError:'int' object is not callable">

So how do I fake things so that xmlrpc knows not to try and call i but
gets the value of i instead?

 

[Fredrik Lundh]

Then the client code can get the value of i like this:
c = xmlrpclib.ServerProxy("address")
c.geti()

but why can't I get the value of i like this?

c.i

you can't. the XML-RPC protocol only supports method calls, not
attribute accesses.

> How can I implement such behaviour?

you could use reflection to automatically wrap attributes on the server
side; e.g.

class foo:
x = 10
# generic getter
def __getattr__(self, key):
if not key.startswith("get_"):
raise AttributeError
value = getattr(self, key[4:])
return lambda: value

f = foo()
print f.x
print f.get_x()

</F>

 

[Irmen de Jong]

but why can't I get the value of i like this?

c.i

How can I implement such behaviour?

Not supported by XMLRpc. Switch to Pyro: http://pyro.sourceforge.net

--Irmen

 

[skip]

sashang> Then the client code can get the value of i like this:
sashang> c = xmlrpclib.ServerProxy("address")
sashang> c.geti()

sashang> but why can't I get the value of i like this?

sashang> c.i

"RPC" stands for "Remote Procedure Call". You're looking for a remote
object access protocol. As Irmen pointed out, Pyro is one such beast,
though it is limited to use with Python. If you need something that's more
language-independent, you might look at SOAP. Personally, XMLRPC has been
sufficient for me for several years.

Skip