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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 tests.spiders import MockServerSpider
from tests.mockserver import MockServer
class InjectArgumentsDownloaderMiddleware:
"""
Make sure downloader middlewares are able to update the keyword arguments
"""
def process_request(self, request, spider):
if request.callback.__name__ == 'parse_downloader_mw':
request.cb_kwargs['from_process_request'] = True
return None
def process_response(self, request, response, spider):
if request.callback.__name__ == 'parse_downloader_mw':
request.cb_kwargs['from_process_response'] = True
return response
class InjectArgumentsSpiderMiddleware:
"""
Make sure spider middlewares are able to update the keyword arguments
"""
def process_start_requests(self, start_requests, spider):
for request in start_requests:
if request.callback.__name__ == 'parse_spider_mw':
request.cb_kwargs['from_process_start_requests'] = True
yield request
def process_spider_input(self, response, spider):
request = response.request
if request.callback.__name__ == 'parse_spider_mw':
request.cb_kwargs['from_process_spider_input'] = True
return None
def process_spider_output(self, response, result, spider):
for element in result:
if isinstance(element, Request) and element.callback.__name__ == 'parse_spider_mw_2':
element.cb_kwargs['from_process_spider_output'] = True
yield element
class KeywordArgumentsSpider(MockServerSpider):
name = 'kwargs'
custom_settings = {
'DOWNLOADER_MIDDLEWARES': {
InjectArgumentsDownloaderMiddleware: 750,
},
'SPIDER_MIDDLEWARES': {
InjectArgumentsSpiderMiddleware: 750,
},
}
checks = list()
def start_requests(self):
data = {'key': 'value', 'number': 123}
yield Request(self.mockserver.url('/first'), self.parse_first, cb_kwargs=data)
yield Request(self.mockserver.url('/general_with'), self.parse_general, cb_kwargs=data)
yield Request(self.mockserver.url('/general_without'), self.parse_general)
yield Request(self.mockserver.url('/no_kwargs'), self.parse_no_kwargs)
yield Request(self.mockserver.url('/default'), self.parse_default, cb_kwargs=data)
yield Request(self.mockserver.url('/takes_less'), self.parse_takes_less, cb_kwargs=data)
yield Request(self.mockserver.url('/takes_more'), self.parse_takes_more, cb_kwargs=data)
yield Request(self.mockserver.url('/downloader_mw'), self.parse_downloader_mw)
yield Request(self.mockserver.url('/spider_mw'), self.parse_spider_mw)
def parse_first(self, response, key, number):
self.checks.append(key == 'value')
self.checks.append(number == 123)
self.crawler.stats.inc_value('boolean_checks', 2)
yield response.follow(
self.mockserver.url('/two'),
self.parse_second,
cb_kwargs={'new_key': 'new_value'})
def parse_second(self, response, new_key):
self.checks.append(new_key == 'new_value')
self.crawler.stats.inc_value('boolean_checks')
def parse_general(self, response, **kwargs):
if response.url.endswith('/general_with'):
self.checks.append(kwargs['key'] == 'value')
self.checks.append(kwargs['number'] == 123)
self.crawler.stats.inc_value('boolean_checks', 2)
elif response.url.endswith('/general_without'):
self.checks.append(kwargs == {})
self.crawler.stats.inc_value('boolean_checks')
def parse_no_kwargs(self, response):
self.checks.append(response.url.endswith('/no_kwargs'))
self.crawler.stats.inc_value('boolean_checks')
def parse_default(self, response, key, number=None, default=99):
self.checks.append(response.url.endswith('/default'))
self.checks.append(key == 'value')
self.checks.append(number == 123)
self.checks.append(default == 99)
self.crawler.stats.inc_value('boolean_checks', 4)
def parse_takes_less(self, response, key):
"""
Should raise
TypeError: parse_takes_less() got an unexpected keyword argument 'number'
"""
def parse_takes_more(self, response, key, number, other):
"""
Should raise
TypeError: parse_takes_more() missing 1 required positional argument: 'other'
"""
def parse_downloader_mw(self, response, from_process_request, from_process_response):
self.checks.append(bool(from_process_request))
self.checks.append(bool(from_process_response))
self.crawler.stats.inc_value('boolean_checks', 2)
def parse_spider_mw(self, response, from_process_spider_input, from_process_start_requests):
self.checks.append(bool(from_process_spider_input))
self.checks.append(bool(from_process_start_requests))
self.crawler.stats.inc_value('boolean_checks', 2)
return Request(self.mockserver.url('/spider_mw_2'), self.parse_spider_mw_2)
def parse_spider_mw_2(self, response, from_process_spider_output):
self.checks.append(bool(from_process_spider_output))
self.crawler.stats.inc_value('boolean_checks', 1)
class CallbackKeywordArgumentsTestCase(TestCase):
maxDiff = None
def setUp(self):
self.mockserver = MockServer()
self.mockserver.__enter__()
self.runner = CrawlerRunner()
def tearDown(self):
self.mockserver.__exit__(None, None, None)
@defer.inlineCallbacks
def test_callback_kwargs(self):
crawler = self.runner.create_crawler(KeywordArgumentsSpider)
with LogCapture() as log:
yield crawler.crawl(mockserver=self.mockserver)
self.assertTrue(all(crawler.spider.checks))
self.assertEqual(len(crawler.spider.checks), crawler.stats.get_value('boolean_checks'))
# check exceptions for argument mismatch
exceptions = {}
for line in log.records:
for key in ('takes_less', 'takes_more'):
if key in line.getMessage():
exceptions[key] = line
self.assertEqual(exceptions['takes_less'].exc_info[0], TypeError)
self.assertEqual(
str(exceptions['takes_less'].exc_info[1]),
"parse_takes_less() got an unexpected keyword argument 'number'"
)
self.assertEqual(exceptions['takes_more'].exc_info[0], TypeError)
self.assertEqual(
str(exceptions['takes_more'].exc_info[1]),
"parse_takes_more() missing 1 required positional argument: 'other'"
)
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