diff --git a/docs/topics/signals.rst b/docs/topics/signals.rst index 3d838fb63..ee9d95836 100644 --- a/docs/topics/signals.rst +++ b/docs/topics/signals.rst @@ -268,6 +268,9 @@ spider_idle You may raise a :exc:`~scrapy.exceptions.DontCloseSpider` exception to prevent the spider from being closed. + Alternatively, you may raise a :exc:`~scrapy.exceptions.CloseSpider` + exception to provide a custom spider closing reason. + This signal does not support returning deferreds from its handlers. :param spider: the spider which has gone idle diff --git a/scrapy/core/engine.py b/scrapy/core/engine.py index dd3225082..949d89e76 100644 --- a/scrapy/core/engine.py +++ b/scrapy/core/engine.py @@ -15,7 +15,8 @@ from twisted.python.failure import Failure from scrapy import signals from scrapy.core.scraper import Scraper -from scrapy.exceptions import DontCloseSpider, ScrapyDeprecationWarning +from scrapy.exceptions import DontCloseSpider, ScrapyDeprecationWarning, \ + CloseSpider from scrapy.http import Response, Request from scrapy.settings import BaseSettings from scrapy.spiders import Spider @@ -325,14 +326,19 @@ class ExecutionEngine: Called when a spider gets idle, i.e. when there are no remaining requests to download or schedule. It can be called multiple times. If a handler for the spider_idle signal raises a DontCloseSpider exception, the spider is not closed until the next loop and this function is guaranteed to be called - (at least) once again. + (at least) once again. A handler can raise CloseSpider to provide a custom closing reason """ assert self.spider is not None # typing - res = self.signals.send_catch_log(signals.spider_idle, spider=self.spider, dont_log=DontCloseSpider) - if any(isinstance(x, Failure) and isinstance(x.value, DontCloseSpider) for _, x in res): + expected_ex = (DontCloseSpider, CloseSpider) + res = self.signals.send_catch_log(signals.spider_idle, spider=self.spider, dont_log=expected_ex) + detected_ex = {ex: x.value + for _, x in res for ex in expected_ex + if isinstance(x, Failure) and isinstance(x.value, ex)} + if DontCloseSpider in detected_ex: return None if self.spider_is_idle(): - self.close_spider(self.spider, reason='finished') + reason = detected_ex[CloseSpider].reason if CloseSpider in detected_ex else 'finished' + self.close_spider(self.spider, reason=reason) def close_spider(self, spider: Spider, reason: str = "cancelled") -> Deferred: """Close (cancel) spider and clear all its outstanding requests""" diff --git a/scrapy/utils/signal.py b/scrapy/utils/signal.py index 115707182..62808f3ce 100644 --- a/scrapy/utils/signal.py +++ b/scrapy/utils/signal.py @@ -1,5 +1,5 @@ """Helper functions for working with signals""" - +import collections import logging from twisted.internet.defer import DeferredList, Deferred @@ -16,15 +16,13 @@ from scrapy.utils.log import failure_to_exc_info logger = logging.getLogger(__name__) -class _IgnoredException(Exception): - pass - - 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', _IgnoredException), StopDownload) + dont_log = named.pop('dont_log', ()) + dont_log = tuple(dont_log) if isinstance(dont_log, collections.Sequence) else (dont_log,) + dont_log += (StopDownload, ) spider = named.get('spider', None) responses = [] for receiver in liveReceivers(getAllReceivers(sender, signal)):