[Twisted-Python] How to get original error message in failure object

[exarkun at twistedmatrix.com]

On 09:42 am, petshmidt at googlemail.com wrote:
>Hello,
>
>if an error occurs in HTTP11ClientProtocol request method
>(twisted.web._newclient) then error is stored in
>RequestGenerationFailed Exception and wrapped in Failure object:
>
>
>        def ebRequestWriting(err):
>            if self._state == 'TRANSMITTING':
>                self._state = 'GENERATION_FAILED'
>                self.transport.loseConnection()
>                 self._finishedRequest.errback(
>                    Failure(RequestGenerationFailed([err])))
>            else:
>                log.err(err, "foo")
>
>but if I print detailed traceback of failure in my code it doesn't
>show all information it contains
>
>Original Failure (err in function above):
>[Failure instance: Traceback: <type 'exceptions.TypeError'>: Data must
>not be unicode
>
>This is detailed traceback, where I don't see the message "Data must
>not be unicode"
>
>*--- Failure #7 (pickled) ---
>Failure: twisted.web._newclient.RequestGenerationFailed:
>[<twisted.python.failure.Failure <type 'exceptions.TypeError'>>]
>*--- End of Failure #7 ---
>None
>
>
>Is there a way to get original error message and where it was raised
>in Twisted code?

See the (documented) `reasons` attribute of `RequestGenerationFailed`.

Jean-Paul