Hello, >>> On Oct 21, 2009, at 4:12 PM, vit...@synapticvision.com wrote: >>> >>>> hi, >>>> how can I chain in defer methods that could raise exception while >>>> showing the exception that coming from method?
This is covered in the Twisted documentation. There's 3 pages I often have reviewed when confused about something: 1. Asynchronous Programming with Twisted (http://twistedmatrix.com/projects/core/documentation/howto/async.html) 2. Deferred Reference (http://twistedmatrix.com/projects/core/documentation/howto/defer.html) 3. Generating Deferreds (http://twistedmatrix.com/projects/core/documentation/howto/gendefer.html) Specifically, the most relevant is the Visual Explanation: http://twistedmatrix.com/projects/core/documentation/howto/defer.html#auto2 This should give you the info you need, but I'll explain a little more anyway. >>>> I mean, if I'll do: >>>> return ( >>>> adc1().abc2().abc3().addErrback("Common2AllException") >>>> ) >>>> than "Common2AllException" will be raised if abc1() raise Exception, >>>> but I'd like to see the adc1() own exception (and not >>>> "Common2AllException") ? If abc1 raises an exception, it's going to go through each step of the callback/errback chain until it finds an errback. If the only thing you have is attached at the very end, then that's where the exception will be handled. > the issue is if adc1() will raise up an exception, than following it > .addErrback() will never be called cause adc1() will exit or raise > Exception. Let's say that your abc() was returning a Deferred. In this case, doing abc().addErrback("Common2AllException") would make sense. However, your example either returns 1 (not a Deferred), or it raises an Exception. Neither one will chain like this. The example is bad. If you can provide a better example, please do. In any case, please review the documentation, especially the "visual explanation" I mentioned above. And finally, do a search on the web for "twisted inlineCallbacks decorator" - that makes writing a lot of Deferred-using code much easier, and helped me out a lot as a beginner. - Paul _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
