Pickle __getstate__ __setstate__ and restoring n/w - beazley pg 172

[dieter]

"Veek. M" <vek.m1234 at gmail.com> writes:

> import socket
> class Client(object):
>  def __init__(self,addr):
>   self.server_addr = addr
>   self.sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
>   self.sock.connect(addr)
>
>  def __getstate__(self):
>   return self.server_addr
>  
>  def __setstate__(self,value):  
>   self.server_addr = value
>   self.sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
>   self.sock.connect(self.server_addr)
> -----------------
>
> We'd use it like so:
> x = Client(192.168.0.1)
> import pickle
> pickle.dump(x) #getstate gets called and returns IP for pickling.
>
> #program exits, we restart it
> x=Client(None)
> x = pickle.load(fh) #Is the IP passed to setstate??????
> x.__setstate__(self, unpickledIP) ???
> Is this correct?

Not completely.

"pickle" operates on objects - and calls "__getstate__" and "__setstate__"
internally. Thus, you get something like:

      client = Client()
      pickle.dump(client, open(fn, "wb"))
      ....
      recreated_client = pickle.load(open(fn, "rb"))