[Twisted-Python] addCallbacks issue
Christopher Armstrong
radix at twistedmatrix.com
Mon Apr 12 18:08:11 EDT 2004
Sorin C. wrote:
> Any idea why addCallbacks fails to bound the error
> handler? I use Twisted 1.2.0.
Read the documentation.
http://twistedmatrix.com/documents/howto/defer
"""
There's another potential gotcha here. There's a method
twisted.internet.defer.Deferred.addCallbacks which is similar to, but
not exactly the same as, addCallback followed by addErrback. In
particular, consider these two cases:
# Case 1
d = getDeferredFromSomewhere()
d.addCallback(callback1)
d.addErrback(errback1)
d.addCallback(callback2)
d.addErrback(errback2)
# Case 2
d = getDeferredFromSomewhere()
d.addCallbacks(callback1, errback1)
d.addCallbacks(callback2, errback2)
If an error occurs in callback1, then for Case 1 errback1 will be called
with the failure. For Case 2, errback2 will be called. Be careful with
your callbacks and errbacks.
"""
--
Twisted | Christopher Armstrong: International Man of Twistery
Radix | Release Manager, Twisted Project
---------+ http://radix.twistedmatrix.com/
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