Hi Jean-Paul,
Here is a sample server and client code that demonstrates the problem
with PB's unserialization code and objects that use __slots__. The
SlotsObject class implements __slots__ and the NoSlotsObject does not.
The problem arises when de-serializing the SlotsObject. The stack trace
is a little different than the original one I posted but the net-effect
is the same; an AttributeError exception.
Thanks,
-ben
sample.py (server and copyable objects):
"""
import sys
import os
from twisted.spread import pb
from twisted.internet import reactor
class BaseObject(object, pb.Copyable, pb.RemoteCopy):
def __init__(self, name):
self.name = name
self.version = "1"
self.release = "2"
def __str__(self):
return "%s-%s-%s" % (self.name, self.version, self.release)
class SlotsObject(BaseObject):
"""
Some object that implements __slots__
"""
__slots__ = ["name", "version", "release"]
def __init__(self):
super(SlotsObject, self).__init__("slots")
class NoSlotsObject(BaseObject):
def __init__(self):
super(NoSlotsObject, self).__init__("no-slots")
class SampleServer(pb.Root, object):
"""
Serve up some objects that implement __slots__.
"""
def remote_getSlotsObject(self):
return SlotsObject()
def remote_getNoSlotsObject(self):
return NoSlotsObject()
def main():
reactor.listenTCP(12346, pb.PBServerFactory(SampleServer()))
reactor.run()
if __name__ == "__main__":
from sample import SlotsObject, NoSlotsObject
main()
"""
sample client code:
"""
import sys
import os
from twisted.internet import reactor
from twisted.spread import pb
from twisted.python import util
from sample import SlotsObject, NoSlotsObject
pb.setUnjellyableForClass(SlotsObject, SlotsObject)
pb.setUnjellyableForClass(NoSlotsObject, NoSlotsObject)
def call(factory, name):
remote = factory.getRootObject()
remote.addCallback(lambda obj: obj.callRemote(name))
remote.addCallback(lambda obj: util.println("name is %r" % obj.name))
remote.addErrback(lambda err: err.printTraceback())
return remote
factory = pb.PBClientFactory()
reactor.connectTCP("localhost", 12346, factory)
call(factory, "getSlotsObject")
remote = call(factory, "getNoSlotsObject")
remote.addCallback(lambda _: reactor.stop())
reactor.run()
"""
Output:
"""
Traceback (most recent call last):
File "/usr/lib64/python2.5/site-packages/twisted/internet/defer.py", line
304, in _startRunCallbacks
self._runCallbacks()
File "/usr/lib64/python2.5/site-packages/twisted/internet/defer.py", line
317, in _runCallbacks
self.result = callback(self.result, *args, **kw)
File "/usr/lib64/python2.5/site-packages/twisted/internet/defer.py", line
281, in _continue
self.unpause()
File "/usr/lib64/python2.5/site-packages/twisted/internet/defer.py", line
277, in unpause
self._runCallbacks()
--- <exception caught here> ---
File "/usr/lib64/python2.5/site-packages/twisted/internet/defer.py", line
317, in _runCallbacks
self.result = callback(self.result, *args, **kw)
File "./sample-client.py", line 17, in <lambda>
remote.addCallback(lambda obj: util.println("name is %r" % obj.name))
exceptions.AttributeError: name
name is 'no-slots'
"""
On Wed, Sep 23, 2009 at 09:42:26PM -0000, [email protected] wrote:
> On 07:06 pm, [email protected] wrote:
> >Hi,
> >
> >I am trying to send new style classes that implement __slots__ with
> >spread.pb.
> >Things seem to go awry when attempting to un-serialize the objects on
> >the
> >client side. I am not sure if this is a known issue. How can I work
> >around
> >this issue?
>
> Perhaps the presence of __slots__ breaks PB's unserialization code. Can
> you share a SSCCE (<http://sscce.org/>)? Then perhaps it may make sense
> to file an enhancement ticket to support this case.
>
> Jean-Paul
>
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