t.p.f.F.trap(self, *errorTypes) : method documentation

Part of twisted.python.failure.Failure View Source

Trap this failure if its type is in a predetermined list.

This allows you to trap a Failure in an error callback. It will be automatically re-raised if it is not a type that you expect.

The reason for having this particular API is because it's very useful in Deferred errback chains:

   def _ebFoo(self, failure):
       r = failure.trap(Spam, Eggs)
       print 'The Failure is due to either Spam or Eggs!'
       if r == Spam:
           print 'Spam did it!'
       elif r == Eggs:
           print 'Eggs did it!'

If the failure is not a Spam or an Eggs, then the Failure will be 'passed on' to the next errback. In Python 2 the Failure will be raised; in Python 3 the underlying exception will be re-raised.

API Documentation for Twisted, generated by pydoctor at 2014-09-18 22:01:49.