| from twisted.internet import reactor |
| from twisted.internet.defer import Deferred |
| from twisted.internet.error import AlreadyCalled |
| |
| |
| class TimeOutError(Exception): pass |
| |
| |
| class DeferredWithTimeout(Deferred): |
| """ |
| Deferred with a timeout. If neither the callback nor the errback method |
| is not called within the given time, the deferred's errback will be called |
| with a TimeOutError() exception. |
| |
| All other uses are the same as of Deferred(). |
| """ |
| def __init__(self, timeout=1.0): |
| Deferred.__init__(self) |
| self._timeout = timeout |
| self.timer = reactor.callLater(timeout, self.timed_out) |
| |
| def timed_out(self): |
| self.errback( |
| TimeOutError('timed out after {} seconds'.format(self._timeout))) |
| |
| def callback(self, result): |
| self._cancel_timer() |
| return Deferred.callback(self, result) |
| |
| def errback(self, fail): |
| self._cancel_timer() |
| return Deferred.errback(self, fail) |
| |
| def cancel(self): |
| self._cancel_timer() |
| return Deferred.cancel(self) |
| |
| def _cancel_timer(self): |
| try: |
| self.timer.cancel() |
| except AlreadyCalled: |
| pass |
| |