[Twisted-Python] Twisted + tlslite
trevp at trevp.net
Sat Mar 13 01:51:41 EST 2004
At 12:25 AM 3/12/2004 -0500, Itamar Shtull-Trauring wrote:
>On Thu, 2004-03-11 at 02:38, Trevor Perrin wrote:
> > One thing I'm not sure about is exception handling. When TLS Lite throws
> > an exception, is there anywhere I can plug-in a handler or something?
>Typically we have callbacks for error conditions. For TLS you usually
>want to close the connection, no? So you'd pass the exception to
>connectionLost wrapped in a Failure, perhaps.
Thanks. I think I managed to implement this, but I'm unsure if I'm trying
to accomplish the right thing, and if I did it properly. If you or anyone
could glance over this, I'd really appreciate it.
Background: there's a class which subclasses ProtocolWrapper. It
overrides dataReceived and does "TLS stuff". The "TLS stuff" will call
ProtocolWrapper.dataReceived when it's processed a whole record.
What I'm trying to do: If the "TLS stuff" raises an exception, the
connection should be closed and the exception should be made available to
the wrapped protocol via connectionLost. If a TLS exception isn't raised,
connectionLost should be called normally, when the connection is shut
down. connectionLost should only be called once when a TLS exception is
raised; i.e., if it's called with a TLS exception, then it *should not* be
called when the TCP connection is closed.
How I'm doing it: I catch TLS exceptions in dataReceived, and then call
through to ProtocolWrapper.connectionLost() with a wrapped error. I keep a
flag to indicate whether connectionLost was called, and only let it be
def dataReceived(self, data):
except tlsErrors, e:
def connectionLost(self, reason):
if not self.connectionLostCalled:
self.connectionLostCalled = True
How does this look?
(the whole thing is here, fwiw: http://trevp.net/tlslite/)
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