[Twisted-Python] If lineReceived returns deferred, then connection is dropped and this deferred given as error message
Marcin.Kasperski at softax.com.pl
Tue Oct 31 10:52:37 EST 2006
I am observing the twisted behaviour which seems rather strange to me.
In short: if lineReceived returns some deferred, then the whole connection is
aborted, moreover, this deferred is returned as error message.
Longer story (the code pieces extracted from quite large app, I have not
yet tried writing small example)
### Crucial code fragments
def lineReceived(self, line):
return defer.succeed(997) # magic value I can recognize easily
def clientConnectionLost(self, connector, reason):
logger.warn("Connection lost. Reason: %s\nTraceback: %s" % (
protocol.ReconnectingClientFactory.clientConnectionLost(self, connector, reason)
reactor.connectTCP(HOST, PORT, SomeFactory(...))
### Things seen in log file
myapp : WARNING Connection lost. Reason: <Deferred at 0xB551E1ECL current result: 997>
Traceback: Traceback (most recent call last):
Failure: <type 'instance'>: <Deferred at 0xB551E1ECL current result: 997>
(you recognized this 997, didn't you?)
### Extra info
1. Removing return defer.succeed() from lineReceived helps.
2. I wanted to return deferreds from lineReceived because I wanted to write unit tests
testing my factory object (and in some cases to check whether all worked correctly
required waiting for some spawned deferred calls).
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