On 04:25 pm, ro...@uw.edu wrote: >In article ><cae_hg6bdail_huf1d7zfiggv-fgxtdqsriq2rt44taqweib...@mail.gmail.com>, >Laurens Van Houtven <_...@lvh.cc> wrote: >>On Thursday, July 12, 2012, Russell E. Owen wrote: >> >> > I'm adding Twisted support to some existing communication code and I >> > have a few questions which I hope are simple. I've been reading the >>API >> > documentation, but if the answers are there I'm missing them. >> > >> > What happens if one tries to write to a protocol.transport that is >>not >> > connected or in an error state? (I'm hoping that this case has >>defined >> > behavior and that it will raise an exception). >> >> >>Not connected usually means that protocol.transport is None >> >> >> > >> > Is there some way to query a protocol to see if it is in a good >>state >> > (connected and no errors)? I realize with callbacks this is not >>usually >> > necessary, but I have a case where it would be helpful (though I can >> > probably manage without it). >> >>Can you elaborate on the case? > >I've found that Twisted sometimes swallows errors unless I am extremely >careful. I would like to be able to check a protocol to make sure it is >operational (connected and happy) as a means of assuring that I've not >missed an error.
Instead, make sure you add errbacks to all your Deferreds. Twisted does not swallow errors. However, a Deferred (that your application keeps a reference to, preventing it from being garbage collected) that has a Failure result and no more errbacks will sit on that Failure until you let the Deferred get garbage collected or add an errback to the Deferred. Jean-Paul >> > When reading raw bytes, is there any way to get the bytes from the >> > protocol? I assume not: that if one wants to buffer the data one >>must do >> > that in the callback. If so, does Twisted provide a suitable buffer >> > class? >> >>The protocol gets dataReceived called. What kind of buffering do you >>want >>to do and why? Would a simple StringIO suffice? > >I read the LineReceiver code (should have done that before asking) and >realize it's buffering using a simple string. I just rewrote that >simple >class to meet my needs and am quite happy. > >-- Russell > > >_______________________________________________ >Twisted-Python mailing list >Twisted-Python@twistedmatrix.com >http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
