Thomas P Jakobsen <thomas....@gmail.com> writes: > By the way, the same thing seem sto happen if the protocol, insted of > asking the user to press enter, does some local computations like > quering a database, sleeping, computing primes or the like. [...]
Right -- callback functions *cannot block*! They must always returns very quickly and use some asynchronous mechanism to signal when a long-running operations is finished. See this FAQ: http://twistedmatrix.com/trac/wiki/FrequentlyAskedQuestions#HowdoIuseDeferredstomakemyblockingcodenon-blocking Twisted has a database abstraction layer that does this for databases: http://twistedmatrix.com/projects/core/documentation/howto/rdbms.html And a threadpool for more general tasks: http://twistedmatrix.com/projects/core/documentation/howto/threading.html For non-blocking access to stdin and stdout there is the twisted.internet.stdio module, see: http://twistedmatrix.com/trac/browser/trunk/doc/core/examples/stdiodemo.py This means that your example should look similar to this:
#!/usr/bin/python
import sys
From optparse import OptionParser
From twisted.internet import reactor, stdio, defer
From twisted.protocols import basic
From viff.field import GF
From viff.runtime import create_runtime, gather_shares, Share
From viff.comparison import Toft05Runtime
From viff.config import load_config
class SomeProtocol(object):
def __init__(self, runtime, io):
self.runtime = runtime
# First do some local stuff.
io.sendLine("Press Enter!")
line = io.readLine()
line.addCallback(self.go)
def go(self, line):
# Now use VIFF.
Zp = GF(30916444023318367583)
a = Share(self.runtime, Zp, value=Zp(0))
b = Share(self.runtime, Zp, value=Zp(1))
c = a > b
c.addCallback(lambda _: self.runtime.shutdown())
class WaitForLine(basic.LineReceiver):
from os import linesep as delimiter
deferred = None
def lineReceived(self, line):
self.sendLine("* received: %s" % line)
if self.deferred:
d, self.deferred = self.deferred, None
d.callback(line)
else:
self.sendLine("** no deferred available!")
def readLine(self):
self.deferred = defer.Deferred()
return self.deferred
if __name__ == "__main__":
io = WaitForLine()
stdio.StandardIO(io)
# Set up VIFF.
parser = OptionParser()
Toft05Runtime.add_options(parser)
options, args = parser.parse_args()
id, players = load_config(args[0])
pre_runtime = create_runtime(id, players, 1, options, Toft05Runtime)
pre_runtime.addCallback(SomeProtocol, io)
reactor.run()
-- Martin Geisler VIFF (Virtual Ideal Functionality Framework) brings easy and efficient SMPC (Secure Multiparty Computation) to Python. See: http://viff.dk/.
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