From 916382e109dc06a57f4631448555953d1fa540b5 Mon Sep 17 00:00:00 2001 From: elacuesta Date: Wed, 18 Dec 2019 12:05:33 -0300 Subject: [PATCH] Add errback parameter to scrapy.spiders.crawl.Rule (#4000) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * Add errback parameter to scrapy.spiders.crawl.Rule * CrawlSpider: optimize by reducing iterations * [test] Rule.errback * [doc] Rule.errback * [doc] Use autoclass in docs/topics/spiders.rst Co-Authored-By: Adrián Chaves * Rule.process_links takes a list * Fix aesthetic issue reported by Flake8 --- docs/topics/spiders.rst | 6 +++++ scrapy/spiders/crawl.py | 60 ++++++++++++++++++++++++++--------------- tests/mockserver.py | 7 +++++ tests/spiders.py | 36 +++++++++++++++++++++++-- tests/test_crawl.py | 18 ++++++++++--- 5 files changed, 101 insertions(+), 26 deletions(-) diff --git a/docs/topics/spiders.rst b/docs/topics/spiders.rst index d65a43afd..b0fb14e24 100644 --- a/docs/topics/spiders.rst +++ b/docs/topics/spiders.rst @@ -414,6 +414,12 @@ Crawling rules from which the request originated as second argument. It must return a ``Request`` object or ``None`` (to filter out the request). + ``errback`` is a callable or a string (in which case a method from the spider + object with that name will be used) to be called if any exception is + raised while processing a request generated by the rule. + It receives a :class:`Twisted Failure ` + instance as first parameter. + CrawlSpider example ~~~~~~~~~~~~~~~~~~~ diff --git a/scrapy/spiders/crawl.py b/scrapy/spiders/crawl.py index a5eb1a518..a2c364c0e 100644 --- a/scrapy/spiders/crawl.py +++ b/scrapy/spiders/crawl.py @@ -16,7 +16,11 @@ from scrapy.utils.python import get_func_args from scrapy.utils.spider import iterate_spider_output -def _identity(request, response): +def _identity(x): + return x + + +def _identity_process_request(request, response): return request @@ -32,17 +36,20 @@ _default_link_extractor = LinkExtractor() class Rule(object): - def __init__(self, link_extractor=None, callback=None, cb_kwargs=None, follow=None, process_links=None, process_request=None): + def __init__(self, link_extractor=None, callback=None, cb_kwargs=None, follow=None, + process_links=None, process_request=None, errback=None): self.link_extractor = link_extractor or _default_link_extractor self.callback = callback + self.errback = errback self.cb_kwargs = cb_kwargs or {} - self.process_links = process_links - self.process_request = process_request or _identity + self.process_links = process_links or _identity + self.process_request = process_request or _identity_process_request self.process_request_argcount = None self.follow = follow if follow is not None else not callback def _compile(self, spider): self.callback = _get_method(self.callback, spider) + self.errback = _get_method(self.errback, spider) self.process_links = _get_method(self.process_links, spider) self.process_request = _get_method(self.process_request, spider) self.process_request_argcount = len(get_func_args(self.process_request)) @@ -76,48 +83,59 @@ class CrawlSpider(Spider): def process_results(self, response, results): return results - def _build_request(self, rule, link): - r = Request(url=link.url, callback=self._response_downloaded) - r.meta.update(rule=rule, link_text=link.text) - return r + def _build_request(self, rule_index, link): + return Request( + url=link.url, + callback=self._callback, + errback=self._errback, + meta=dict(rule=rule_index, link_text=link.text), + ) def _requests_to_follow(self, response): if not isinstance(response, HtmlResponse): return seen = set() - for n, rule in enumerate(self._rules): + for rule_index, rule in enumerate(self._rules): links = [lnk for lnk in rule.link_extractor.extract_links(response) if lnk not in seen] - if links and rule.process_links: - links = rule.process_links(links) - for link in links: + for link in rule.process_links(links): seen.add(link) - request = self._build_request(n, link) + request = self._build_request(rule_index, link) yield rule._process_request(request, response) - def _response_downloaded(self, response): + def _callback(self, response): rule = self._rules[response.meta['rule']] return self._parse_response(response, rule.callback, rule.cb_kwargs, rule.follow) + def _errback(self, failure): + rule = self._rules[failure.request.meta['rule']] + return self._handle_failure(failure, rule.errback) + def _parse_response(self, response, callback, cb_kwargs, follow=True): if callback: cb_res = callback(response, **cb_kwargs) or () cb_res = self.process_results(response, cb_res) - for requests_or_item in iterate_spider_output(cb_res): - yield requests_or_item + for request_or_item in iterate_spider_output(cb_res): + yield request_or_item if follow and self._follow_links: for request_or_item in self._requests_to_follow(response): yield request_or_item + def _handle_failure(self, failure, errback): + if errback: + results = errback(failure) or () + for request_or_item in iterate_spider_output(results): + yield request_or_item + def _compile_rules(self): - self._rules = [copy.copy(r) for r in self.rules] - for rule in self._rules: - rule._compile(self) + self._rules = [] + for rule in self.rules: + self._rules.append(copy.copy(rule)) + self._rules[-1]._compile(self) @classmethod def from_crawler(cls, crawler, *args, **kwargs): spider = super(CrawlSpider, cls).from_crawler(crawler, *args, **kwargs) - spider._follow_links = crawler.settings.getbool( - 'CRAWLSPIDER_FOLLOW_LINKS', True) + spider._follow_links = crawler.settings.getbool('CRAWLSPIDER_FOLLOW_LINKS', True) return spider diff --git a/tests/mockserver.py b/tests/mockserver.py index fe28176d4..a45277db9 100644 --- a/tests/mockserver.py +++ b/tests/mockserver.py @@ -164,6 +164,12 @@ class Drop(Partial): request.finish() +class ArbitraryLengthPayloadResource(LeafResource): + + def render(self, request): + return request.content.read() + + class Root(Resource): def __init__(self): @@ -177,6 +183,7 @@ class Root(Resource): self.putChild(b"echo", Echo()) self.putChild(b"payload", PayloadResource()) self.putChild(b"xpayload", EncodingResourceWrapper(PayloadResource(), [GzipEncoderFactory()])) + self.putChild(b"alpayload", ArbitraryLengthPayloadResource()) try: from tests import tests_datadir self.putChild(b"files", File(os.path.join(tests_datadir, 'test_site/files/'))) diff --git a/tests/spiders.py b/tests/spiders.py index 981bd2eb8..39c8da0b6 100644 --- a/tests/spiders.py +++ b/tests/spiders.py @@ -1,14 +1,14 @@ """ Some spiders used for testing and benchmarking """ - import time from urllib.parse import urlencode -from scrapy.spiders import Spider from scrapy.http import Request from scrapy.item import Item from scrapy.linkextractors import LinkExtractor +from scrapy.spiders import Spider +from scrapy.spiders.crawl import CrawlSpider, Rule class MockServerSpider(Spider): @@ -184,3 +184,35 @@ class DuplicateStartRequestsSpider(MockServerSpider): def parse(self, response): self.visited += 1 + + +class CrawlSpiderWithErrback(MockServerSpider, CrawlSpider): + name = 'crawl_spider_with_errback' + custom_settings = { + 'RETRY_HTTP_CODES': [], # no need to retry + } + rules = ( + Rule(LinkExtractor(), callback='callback', errback='errback', follow=True), + ) + + def start_requests(self): + test_body = b""" + + Page title<title></head> + <body> + <p><a href="/status?n=200">Item 200</a></p> <!-- callback --> + <p><a href="/status?n=201">Item 201</a></p> <!-- callback --> + <p><a href="/status?n=404">Item 404</a></p> <!-- errback --> + <p><a href="/status?n=500">Item 500</a></p> <!-- errback --> + <p><a href="/status?n=501">Item 501</a></p> <!-- errback --> + </body> + </html> + """ + url = self.mockserver.url("/alpayload") + yield Request(url, method="POST", body=test_body) + + def callback(self, response): + self.logger.info('[callback] status %i', response.status) + + def errback(self, failure): + self.logger.info('[errback] status %i', failure.value.response.status) diff --git a/tests/test_crawl.py b/tests/test_crawl.py index 3307899b7..76f87458b 100644 --- a/tests/test_crawl.py +++ b/tests/test_crawl.py @@ -5,12 +5,12 @@ from testfixtures import LogCapture from twisted.internet import defer from twisted.trial.unittest import TestCase -from scrapy.http import Request from scrapy.crawler import CrawlerRunner +from scrapy.http import Request from scrapy.utils.python import to_unicode -from tests.spiders import FollowAllSpider, DelaySpider, SimpleSpider, \ - BrokenStartRequestsSpider, SingleRequestSpider, DuplicateStartRequestsSpider from tests.mockserver import MockServer +from tests.spiders import (FollowAllSpider, DelaySpider, SimpleSpider, BrokenStartRequestsSpider, + SingleRequestSpider, DuplicateStartRequestsSpider, CrawlSpiderWithErrback) class CrawlTestCase(TestCase): @@ -277,3 +277,15 @@ with multiples lines self._assert_retried(log) self.assertIn("Got response 200", str(log)) + + @defer.inlineCallbacks + def test_crawlspider_with_errback(self): + self.runner.crawl(CrawlSpiderWithErrback, mockserver=self.mockserver) + + with LogCapture() as log: + yield self.runner.join() + + self.assertIn("[callback] status 200", str(log)) + self.assertIn("[callback] status 201", str(log)) + self.assertIn("[errback] status 404", str(log)) + self.assertIn("[errback] status 500", str(log))