def sendRobust( signal=Any, sender=Anonymous, *arguments, **named ): """Send signal from sender to all connected receivers catching errors signal -- (hashable) signal value, see connect for details sender -- the sender of the signal if Any, only receivers registered for Any will receive the message. if Anonymous, only receivers registered to receive messages from Anonymous or Any will receive the message Otherwise can be any python object (normally one registered with a connect if you actually want something to occur). arguments -- positional arguments which will be passed to *all* receivers. Note that this may raise TypeErrors if the receivers do not allow the particular arguments. Note also that arguments are applied before named arguments, so they should be used with care. named -- named arguments which will be filtered according to the parameters of the receivers to only provide those acceptable to the receiver. Return a list of tuple pairs [(receiver, response), ... ] if any receiver raises an error (specifically any subclass of Exception), the error instance is returned as the result for that receiver. """ # Call each receiver with whatever arguments it can accept. # Return a list of tuple pairs [(receiver, response), ... ]. responses = [] for receiver in liveReceivers(getAllReceivers(sender, signal)): try: response = robustApply( receiver, signal=signal, sender=sender, *arguments, **named ) except Exception as err: responses.append((receiver, err)) else: responses.append((receiver, response)) return responses
def send_catch_log_deferred(signal=Any, sender=Anonymous, *arguments, **named):
"""Like send_catch_log but supports returning deferreds on signal handlers.
Returns a deferred that gets fired once all signal handlers deferreds were
fired.
"""
def logerror(failure, recv):
if dont_log is None or not isinstance(failure.value, dont_log):
log.err(failure, "Error caught on signal handler: %s" % recv, \
spider=spider)
return failure
dont_log = named.pop('dont_log', None)
spider = named.get('spider', None)
dfds = []
for receiver in liveReceivers(getAllReceivers(sender, signal)):
d = maybeDeferred(robustApply, receiver, signal=signal, sender=sender,
*arguments, **named)
d.addErrback(logerror, receiver)
d.addBoth(lambda result: (receiver, result))
dfds.append(d)
d = DeferredList(dfds)
d.addCallback(lambda out: [x[1] for x in out])
return d
def send_catch_log(signal=Any, sender=Anonymous, *arguments, **named):
"""Like pydispatcher.robust.sendRobust but it also logs errors and returns
Failures instead of exceptions.
"""
dont_log = named.pop('dont_log', None)
spider = named.get('spider', None)
responses = []
for receiver in liveReceivers(getAllReceivers(sender, signal)):
try:
response = robustApply(receiver, signal=signal, sender=sender,
*arguments, **named)
if isinstance(response, Deferred):
log.msg(format="Cannot return deferreds from signal handler: %(receiver)s",
level=log.ERROR, spider=spider, receiver=receiver)
except dont_log:
result = Failure()
except Exception:
result = Failure()
log.err(result, "Error caught on signal handler: %s" % receiver, \
spider=spider)
else:
result = response
responses.append((receiver, result))
return responses
def disconnect_all(signal=Any, sender=Any):
"""Disconnect all signal handlers. Useful for cleaning up after running
tests
"""
for receiver in liveReceivers(getAllReceivers(sender, signal)):
disconnect(receiver, signal=signal, sender=sender)