Thanks for the tip, I've gone that route as it was the simplest to realize.
Since I had centralized all calls
to transport.write() in a wrapper in the code, I didn't had to implement an
ITransport ..
It seems to "work" (modulo the cautions you iterated) .. and I no longer use
reactor internals.
I had to introduce a layer of buffering though (which kicks in as soon as I do
a "synch"/"chopped" send .. test prg below.
Thanks again, cheers
=== CLIENT ===
import binascii, time
from collections import deque
from twisted.internet import reactor, protocol
from twisted.internet.defer import inlineCallbacks, Deferred
class TricklingClientProtocol(protocol.Protocol):
def __init__(self):
self.send_queue = deque()
self.triggered = False
def _trigger(self):
if not self.triggered:
self.triggered = True
self._send()
def _send(self):
if len(self.send_queue) > 0:
e = self.send_queue.popleft()
self.transport.write(e)
reactor.callLater(0.000001, self._send)
else:
self.triggered = False
def send(self, data, sync = False, chopsize = None):
if chopsize > 0:
i = 0
n = len(data)
done = False
while not done:
j = i + chopsize
if j >= n:
done = True
j = n
self.send_queue.append(data[i:j])
i += chopsize
self._trigger()
#print "chopped send"
else:
if sync or len(self.send_queue) > 0:
self.send_queue.append(data)
self._trigger()
#print "synced send"
else:
self.transport.write(data)
#print "normal send"
def connectionMade(self):
self.transport.setTcpNoDelay(True)
self.part1()
def part1(self):
LEN = 50
self.send("123" * LEN)
for i in xrange(0, LEN):
self.send("456", sync = True)
self.send("789" * LEN, chopsize = 1)
self.send("123" * LEN)
reactor.callLater(0.3, self.part2)
def part2(self):
self.send("xyz" * 5)
self.send("abc" * 5, chopsize = 1)
reactor.callLater(5, self.transport.loseConnection)
class TricklingClientFactory(protocol.ClientFactory):
protocol = TricklingClientProtocol
def clientConnectionFailed(self, connector, reason):
reactor.stop()
def clientConnectionLost(self, connector, reason):
reactor.stop()
if __name__ == '__main__':
factory = TricklingClientFactory()
reactor.connectTCP("localhost", 9000, factory)
reactor.run()
=== SERVER ====
import binascii
from twisted.internet import reactor, protocol
class TricklingServerProtocol(protocol.Protocol):
def __init__(self):
pass
def connectionMade(self):
print "client accepted"
self.transport.setTcpNoDelay(True)
self.stats = {}
def connectionLost(self, reason):
print "client lost"
for s in sorted(self.stats):
print "%dx chop of length %d" % (self.stats[s], s)
def dataReceived(self, data):
l = len(data)
self.stats[l] = self.stats.get(l, 0) + 1
#print data
class TricklingServerFactory(protocol.ServerFactory):
protocol = TricklingServerProtocol
def __init__(self):
pass
def startFactory(self):
pass
def stopFactory(self):
pass
if __name__ == '__main__':
factory = TricklingServerFactory()
reactor.listenTCP(9000, factory)
reactor.run()
Von: [email protected]
[mailto:[email protected]] Im Auftrag von Glyph Lefkowitz
Gesendet: Freitag, 12. August 2011 06:06
An: Twisted general discussion
Betreff: Re: [Twisted-Python] Flush socket
On Aug 11, 2011, at 7:43 PM,
[email protected]<mailto:[email protected]> wrote:
This will always be a somewhat unreliable way to test a remote process's
handling of packetization, since there are still two TCP/IP stacks which
can mess around with the data in a variety of ways, but it's as good as
you can do if you want to use normal sockets for this testing.
This bears repeating. It's really unreliable. Really. The sizes of buffers
passed to send() and recv() bear only a coincidental resemblance to each other;
one test setup may reproduce them reliably when the next will suddenly behave
completely differently. If you want even a reasonably reliable heuristic here,
you need to send() and then introduce a delay. You can do this without your
own IWriteDescriptor implementation though; just implement an ITransport that
does its write() by breaking things up and then calling the underlying write()
with callLater()s in-between.
-glyph
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