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Conditional request attribute binding for responses (#4632)
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Original file line number | Diff line number | Diff line change |
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from twisted.internet import defer | ||
from twisted.trial.unittest import TestCase | ||
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from scrapy import Request, signals | ||
from scrapy.crawler import CrawlerRunner | ||
from scrapy.http.response import Response | ||
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from testfixtures import LogCapture | ||
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from tests.mockserver import MockServer | ||
from tests.spiders import SingleRequestSpider | ||
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OVERRIDEN_URL = "https://example.org" | ||
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class ProcessResponseMiddleware: | ||
def process_response(self, request, response, spider): | ||
return response.replace(request=Request(OVERRIDEN_URL)) | ||
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class RaiseExceptionRequestMiddleware: | ||
def process_request(self, request, spider): | ||
1 / 0 | ||
return request | ||
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class CatchExceptionOverrideRequestMiddleware: | ||
def process_exception(self, request, exception, spider): | ||
return Response( | ||
url="http://localhost/", | ||
body=b"Caught " + exception.__class__.__name__.encode("utf-8"), | ||
request=Request(OVERRIDEN_URL), | ||
) | ||
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class CatchExceptionDoNotOverrideRequestMiddleware: | ||
def process_exception(self, request, exception, spider): | ||
return Response( | ||
url="http://localhost/", | ||
body=b"Caught " + exception.__class__.__name__.encode("utf-8"), | ||
) | ||
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class AlternativeCallbacksSpider(SingleRequestSpider): | ||
name = "alternative_callbacks_spider" | ||
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def alt_callback(self, response, foo=None): | ||
self.logger.info("alt_callback was invoked with foo=%s", foo) | ||
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class AlternativeCallbacksMiddleware: | ||
def process_response(self, request, response, spider): | ||
new_request = request.replace( | ||
url=OVERRIDEN_URL, | ||
callback=spider.alt_callback, | ||
cb_kwargs={"foo": "bar"}, | ||
) | ||
return response.replace(request=new_request) | ||
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class CrawlTestCase(TestCase): | ||
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def setUp(self): | ||
self.mockserver = MockServer() | ||
self.mockserver.__enter__() | ||
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def tearDown(self): | ||
self.mockserver.__exit__(None, None, None) | ||
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@defer.inlineCallbacks | ||
def test_response_200(self): | ||
url = self.mockserver.url("/status?n=200") | ||
crawler = CrawlerRunner().create_crawler(SingleRequestSpider) | ||
yield crawler.crawl(seed=url, mockserver=self.mockserver) | ||
response = crawler.spider.meta["responses"][0] | ||
self.assertEqual(response.request.url, url) | ||
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@defer.inlineCallbacks | ||
def test_response_error(self): | ||
for status in ("404", "500"): | ||
url = self.mockserver.url("/status?n={}".format(status)) | ||
crawler = CrawlerRunner().create_crawler(SingleRequestSpider) | ||
yield crawler.crawl(seed=url, mockserver=self.mockserver) | ||
failure = crawler.spider.meta["failure"] | ||
response = failure.value.response | ||
self.assertEqual(failure.request.url, url) | ||
self.assertEqual(response.request.url, url) | ||
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@defer.inlineCallbacks | ||
def test_downloader_middleware_raise_exception(self): | ||
url = self.mockserver.url("/status?n=200") | ||
runner = CrawlerRunner(settings={ | ||
"DOWNLOADER_MIDDLEWARES": { | ||
__name__ + ".RaiseExceptionRequestMiddleware": 590, | ||
}, | ||
}) | ||
crawler = runner.create_crawler(SingleRequestSpider) | ||
yield crawler.crawl(seed=url, mockserver=self.mockserver) | ||
failure = crawler.spider.meta["failure"] | ||
self.assertEqual(failure.request.url, url) | ||
self.assertIsInstance(failure.value, ZeroDivisionError) | ||
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@defer.inlineCallbacks | ||
def test_downloader_middleware_override_request_in_process_response(self): | ||
""" | ||
Downloader middleware which returns a response with an specific 'request' attribute. | ||
* The spider callback should receive the overriden response.request | ||
* Handlers listening to the response_received signal should receive the overriden response.request | ||
* The "crawled" log message should show the overriden response.request | ||
""" | ||
signal_params = {} | ||
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def signal_handler(response, request, spider): | ||
signal_params["response"] = response | ||
signal_params["request"] = request | ||
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url = self.mockserver.url("/status?n=200") | ||
runner = CrawlerRunner(settings={ | ||
"DOWNLOADER_MIDDLEWARES": { | ||
__name__ + ".ProcessResponseMiddleware": 595, | ||
} | ||
}) | ||
crawler = runner.create_crawler(SingleRequestSpider) | ||
crawler.signals.connect(signal_handler, signal=signals.response_received) | ||
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with LogCapture() as log: | ||
yield crawler.crawl(seed=url, mockserver=self.mockserver) | ||
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response = crawler.spider.meta["responses"][0] | ||
self.assertEqual(response.request.url, OVERRIDEN_URL) | ||
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self.assertEqual(signal_params["response"].url, url) | ||
self.assertEqual(signal_params["request"].url, OVERRIDEN_URL) | ||
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log.check_present( | ||
("scrapy.core.engine", "DEBUG", "Crawled (200) <GET {}> (referer: None)".format(OVERRIDEN_URL)), | ||
) | ||
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@defer.inlineCallbacks | ||
def test_downloader_middleware_override_in_process_exception(self): | ||
""" | ||
An exception is raised but caught by the next middleware, which | ||
returns a Response with a specific 'request' attribute. | ||
The spider callback should receive the overriden response.request | ||
""" | ||
url = self.mockserver.url("/status?n=200") | ||
runner = CrawlerRunner(settings={ | ||
"DOWNLOADER_MIDDLEWARES": { | ||
__name__ + ".RaiseExceptionRequestMiddleware": 590, | ||
__name__ + ".CatchExceptionOverrideRequestMiddleware": 595, | ||
}, | ||
}) | ||
crawler = runner.create_crawler(SingleRequestSpider) | ||
yield crawler.crawl(seed=url, mockserver=self.mockserver) | ||
response = crawler.spider.meta["responses"][0] | ||
self.assertEqual(response.body, b"Caught ZeroDivisionError") | ||
self.assertEqual(response.request.url, OVERRIDEN_URL) | ||
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@defer.inlineCallbacks | ||
def test_downloader_middleware_do_not_override_in_process_exception(self): | ||
""" | ||
An exception is raised but caught by the next middleware, which | ||
returns a Response without a specific 'request' attribute. | ||
The spider callback should receive the original response.request | ||
""" | ||
url = self.mockserver.url("/status?n=200") | ||
runner = CrawlerRunner(settings={ | ||
"DOWNLOADER_MIDDLEWARES": { | ||
__name__ + ".RaiseExceptionRequestMiddleware": 590, | ||
__name__ + ".CatchExceptionDoNotOverrideRequestMiddleware": 595, | ||
}, | ||
}) | ||
crawler = runner.create_crawler(SingleRequestSpider) | ||
yield crawler.crawl(seed=url, mockserver=self.mockserver) | ||
response = crawler.spider.meta["responses"][0] | ||
self.assertEqual(response.body, b"Caught ZeroDivisionError") | ||
self.assertEqual(response.request.url, url) | ||
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@defer.inlineCallbacks | ||
def test_downloader_middleware_alternative_callback(self): | ||
""" | ||
Downloader middleware which returns a response with a | ||
specific 'request' attribute, with an alternative callback | ||
""" | ||
runner = CrawlerRunner(settings={ | ||
"DOWNLOADER_MIDDLEWARES": { | ||
__name__ + ".AlternativeCallbacksMiddleware": 595, | ||
} | ||
}) | ||
crawler = runner.create_crawler(AlternativeCallbacksSpider) | ||
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with LogCapture() as log: | ||
url = self.mockserver.url("/status?n=200") | ||
yield crawler.crawl(seed=url, mockserver=self.mockserver) | ||
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log.check_present( | ||
("alternative_callbacks_spider", "INFO", "alt_callback was invoked with foo=bar"), | ||
) |