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from testfixtures import LogCapture
from twisted.internet import defer
from twisted.trial.unittest import TestCase
from scrapy import Request, signals
from scrapy.http.response import Response
from scrapy.utils.test import get_crawler
from tests.mockserver import MockServer
from tests.spiders import SingleRequestSpider
OVERRIDDEN_URL = "https://example.org"
class ProcessResponseMiddleware:
def process_response(self, request, response, spider):
return response.replace(request=Request(OVERRIDDEN_URL))
class RaiseExceptionRequestMiddleware:
def process_request(self, request, spider):
1 / 0
return request
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(OVERRIDDEN_URL),
)
class CatchExceptionDoNotOverrideRequestMiddleware:
def process_exception(self, request, exception, spider):
return Response(
url="http://localhost/",
body=b"Caught " + exception.__class__.__name__.encode("utf-8"),
)
class AlternativeCallbacksSpider(SingleRequestSpider):
name = "alternative_callbacks_spider"
def alt_callback(self, response, foo=None):
self.logger.info("alt_callback was invoked with foo=%s", foo)
class AlternativeCallbacksMiddleware:
def process_response(self, request, response, spider):
new_request = request.replace(
url=OVERRIDDEN_URL,
callback=spider.alt_callback,
cb_kwargs={"foo": "bar"},
)
return response.replace(request=new_request)
class TestCrawl(TestCase):
@classmethod
def setUpClass(cls):
cls.mockserver = MockServer()
cls.mockserver.__enter__()
@classmethod
def tearDownClass(cls):
cls.mockserver.__exit__(None, None, None)
@defer.inlineCallbacks
def test_response_200(self):
url = self.mockserver.url("/status?n=200")
crawler = get_crawler(SingleRequestSpider)
yield crawler.crawl(seed=url, mockserver=self.mockserver)
response = crawler.spider.meta["responses"][0]
assert response.request.url == url
@defer.inlineCallbacks
def test_response_error(self):
for status in ("404", "500"):
url = self.mockserver.url(f"/status?n={status}")
crawler = get_crawler(SingleRequestSpider)
yield crawler.crawl(seed=url, mockserver=self.mockserver)
failure = crawler.spider.meta["failure"]
response = failure.value.response
assert failure.request.url == url
assert response.request.url == url
@defer.inlineCallbacks
def test_downloader_middleware_raise_exception(self):
url = self.mockserver.url("/status?n=200")
crawler = get_crawler(
SingleRequestSpider,
{
"DOWNLOADER_MIDDLEWARES": {
RaiseExceptionRequestMiddleware: 590,
},
},
)
yield crawler.crawl(seed=url, mockserver=self.mockserver)
failure = crawler.spider.meta["failure"]
assert failure.request.url == url
assert isinstance(failure.value, ZeroDivisionError)
@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 overridden response.request
* Handlers listening to the response_received signal should receive the overridden response.request
* The "crawled" log message should show the overridden response.request
"""
signal_params = {}
def signal_handler(response, request, spider):
signal_params["response"] = response
signal_params["request"] = request
url = self.mockserver.url("/status?n=200")
crawler = get_crawler(
SingleRequestSpider,
{
"DOWNLOADER_MIDDLEWARES": {
ProcessResponseMiddleware: 595,
}
},
)
crawler.signals.connect(signal_handler, signal=signals.response_received)
with LogCapture() as log:
yield crawler.crawl(seed=url, mockserver=self.mockserver)
response = crawler.spider.meta["responses"][0]
assert response.request.url == OVERRIDDEN_URL
assert signal_params["response"].url == url
assert signal_params["request"].url == OVERRIDDEN_URL
log.check_present(
(
"scrapy.core.engine",
"DEBUG",
f"Crawled (200) <GET {OVERRIDDEN_URL}> (referer: None)",
),
)
@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 overridden response.request
"""
url = self.mockserver.url("/status?n=200")
crawler = get_crawler(
SingleRequestSpider,
{
"DOWNLOADER_MIDDLEWARES": {
RaiseExceptionRequestMiddleware: 590,
CatchExceptionOverrideRequestMiddleware: 595,
},
},
)
yield crawler.crawl(seed=url, mockserver=self.mockserver)
response = crawler.spider.meta["responses"][0]
assert response.body == b"Caught ZeroDivisionError"
assert response.request.url == OVERRIDDEN_URL
@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")
crawler = get_crawler(
SingleRequestSpider,
{
"DOWNLOADER_MIDDLEWARES": {
RaiseExceptionRequestMiddleware: 590,
CatchExceptionDoNotOverrideRequestMiddleware: 595,
},
},
)
yield crawler.crawl(seed=url, mockserver=self.mockserver)
response = crawler.spider.meta["responses"][0]
assert response.body == b"Caught ZeroDivisionError"
assert response.request.url == url
@defer.inlineCallbacks
def test_downloader_middleware_alternative_callback(self):
"""
Downloader middleware which returns a response with a
specific 'request' attribute, with an alternative callback
"""
crawler = get_crawler(
AlternativeCallbacksSpider,
{
"DOWNLOADER_MIDDLEWARES": {
AlternativeCallbacksMiddleware: 595,
}
},
)
with LogCapture() as log:
url = self.mockserver.url("/status?n=200")
yield crawler.crawl(seed=url, mockserver=self.mockserver)
log.check_present(
(
"alternative_callbacks_spider",
"INFO",
"alt_callback was invoked with foo=bar",
),
)
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