from __future__ import print_function import time import tempfile import shutil import unittest import email.utils from contextlib import contextmanager import pytest from scrapy.http import Response, HtmlResponse, Request from scrapy.spiders import Spider from scrapy.settings import Settings from scrapy.exceptions import IgnoreRequest from scrapy.utils.test import get_crawler from scrapy.downloadermiddlewares.httpcache import HttpCacheMiddleware class _BaseTest(unittest.TestCase): storage_class = 'scrapy.extensions.httpcache.DbmCacheStorage' policy_class = 'scrapy.extensions.httpcache.RFC2616Policy' def setUp(self): self.yesterday = email.utils.formatdate(time.time() - 86400) self.today = email.utils.formatdate() self.tomorrow = email.utils.formatdate(time.time() + 86400) self.crawler = get_crawler(Spider) self.spider = self.crawler._create_spider('example.com') self.tmpdir = tempfile.mkdtemp() self.request = Request('http://www.example.com', headers={'User-Agent': 'test'}) self.response = Response('http://www.example.com', headers={'Content-Type': 'text/html'}, body=b'test body', status=202) self.crawler.stats.open_spider(self.spider) def tearDown(self): self.crawler.stats.close_spider(self.spider, '') shutil.rmtree(self.tmpdir) def _get_settings(self, **new_settings): settings = { 'HTTPCACHE_ENABLED': True, 'HTTPCACHE_DIR': self.tmpdir, 'HTTPCACHE_EXPIRATION_SECS': 1, 'HTTPCACHE_IGNORE_HTTP_CODES': [], 'HTTPCACHE_POLICY': self.policy_class, 'HTTPCACHE_STORAGE': self.storage_class, } settings.update(new_settings) return Settings(settings) @contextmanager def _storage(self, **new_settings): with self._middleware(**new_settings) as mw: yield mw.storage @contextmanager def _policy(self, **new_settings): with self._middleware(**new_settings) as mw: yield mw.policy @contextmanager def _middleware(self, **new_settings): settings = self._get_settings(**new_settings) mw = HttpCacheMiddleware(settings, self.crawler.stats) mw.spider_opened(self.spider) try: yield mw finally: mw.spider_closed(self.spider) def assertEqualResponse(self, response1, response2): self.assertEqual(response1.url, response2.url) self.assertEqual(response1.status, response2.status) self.assertEqual(response1.headers, response2.headers) self.assertEqual(response1.body, response2.body) def assertEqualRequest(self, request1, request2): self.assertEqual(request1.url, request2.url) self.assertEqual(request1.headers, request2.headers) self.assertEqual(request1.body, request2.body) def assertEqualRequestButWithCacheValidators(self, request1, request2): self.assertEqual(request1.url, request2.url) assert not b'If-None-Match' in request1.headers assert not b'If-Modified-Since' in request1.headers assert any(h in request2.headers for h in (b'If-None-Match', b'If-Modified-Since')) self.assertEqual(request1.body, request2.body) def test_dont_cache(self): with self._middleware() as mw: self.request.meta['dont_cache'] = True mw.process_response(self.request, self.response, self.spider) self.assertEqual(mw.storage.retrieve_response(self.spider, self.request), None) with self._middleware() as mw: self.request.meta['dont_cache'] = False mw.process_response(self.request, self.response, self.spider) if mw.policy.should_cache_response(self.response, self.request): self.assertIsInstance(mw.storage.retrieve_response(self.spider, self.request), self.response.__class__) class DefaultStorageTest(_BaseTest): def test_storage(self): with self._storage() as storage: request2 = self.request.copy() assert storage.retrieve_response(self.spider, request2) is None storage.store_response(self.spider, self.request, self.response) response2 = storage.retrieve_response(self.spider, request2) assert isinstance(response2, HtmlResponse) # content-type header self.assertEqualResponse(self.response, response2) time.sleep(2) # wait for cache to expire assert storage.retrieve_response(self.spider, request2) is None def test_storage_never_expire(self): with self._storage(HTTPCACHE_EXPIRATION_SECS=0) as storage: assert storage.retrieve_response(self.spider, self.request) is None storage.store_response(self.spider, self.request, self.response) time.sleep(0.5) # give the chance to expire assert storage.retrieve_response(self.spider, self.request) class DbmStorageTest(DefaultStorageTest): storage_class = 'scrapy.extensions.httpcache.DbmCacheStorage' class DbmStorageWithCustomDbmModuleTest(DbmStorageTest): dbm_module = 'tests.mocks.dummydbm' def _get_settings(self, **new_settings): new_settings.setdefault('HTTPCACHE_DBM_MODULE', self.dbm_module) return super(DbmStorageWithCustomDbmModuleTest, self)._get_settings(**new_settings) def test_custom_dbm_module_loaded(self): # make sure our dbm module has been loaded with self._storage() as storage: self.assertEqual(storage.dbmodule.__name__, self.dbm_module) class FilesystemStorageTest(DefaultStorageTest): storage_class = 'scrapy.extensions.httpcache.FilesystemCacheStorage' class FilesystemStorageGzipTest(FilesystemStorageTest): def _get_settings(self, **new_settings): new_settings.setdefault('HTTPCACHE_GZIP', True) return super(FilesystemStorageTest, self)._get_settings(**new_settings) class LeveldbStorageTest(DefaultStorageTest): pytest.importorskip('leveldb') storage_class = 'scrapy.extensions.httpcache.LeveldbCacheStorage' class DummyPolicyTest(_BaseTest): policy_class = 'scrapy.extensions.httpcache.DummyPolicy' def test_middleware(self): with self._middleware() as mw: assert mw.process_request(self.request, self.spider) is None mw.process_response(self.request, self.response, self.spider) response = mw.process_request(self.request, self.spider) assert isinstance(response, HtmlResponse) self.assertEqualResponse(self.response, response) assert 'cached' in response.flags def test_different_request_response_urls(self): with self._middleware() as mw: req = Request('http://host.com/path') res = Response('http://host2.net/test.html') assert mw.process_request(req, self.spider) is None mw.process_response(req, res, self.spider) cached = mw.process_request(req, self.spider) assert isinstance(cached, Response) self.assertEqualResponse(res, cached) assert 'cached' in cached.flags def test_middleware_ignore_missing(self): with self._middleware(HTTPCACHE_IGNORE_MISSING=True) as mw: self.assertRaises(IgnoreRequest, mw.process_request, self.request, self.spider) mw.process_response(self.request, self.response, self.spider) response = mw.process_request(self.request, self.spider) assert isinstance(response, HtmlResponse) self.assertEqualResponse(self.response, response) assert 'cached' in response.flags def test_middleware_ignore_schemes(self): # http responses are cached by default req, res = Request('http://test.com/'), Response('http://test.com/') with self._middleware() as mw: assert mw.process_request(req, self.spider) is None mw.process_response(req, res, self.spider) cached = mw.process_request(req, self.spider) assert isinstance(cached, Response), type(cached) self.assertEqualResponse(res, cached) assert 'cached' in cached.flags # file response is not cached by default req, res = Request('file:///tmp/t.txt'), Response('file:///tmp/t.txt') with self._middleware() as mw: assert mw.process_request(req, self.spider) is None mw.process_response(req, res, self.spider) assert mw.storage.retrieve_response(self.spider, req) is None assert mw.process_request(req, self.spider) is None # s3 scheme response is cached by default req, res = Request('s3://bucket/key'), Response('http://bucket/key') with self._middleware() as mw: assert mw.process_request(req, self.spider) is None mw.process_response(req, res, self.spider) cached = mw.process_request(req, self.spider) assert isinstance(cached, Response), type(cached) self.assertEqualResponse(res, cached) assert 'cached' in cached.flags # ignore s3 scheme req, res = Request('s3://bucket/key2'), Response('http://bucket/key2') with self._middleware(HTTPCACHE_IGNORE_SCHEMES=['s3']) as mw: assert mw.process_request(req, self.spider) is None mw.process_response(req, res, self.spider) assert mw.storage.retrieve_response(self.spider, req) is None assert mw.process_request(req, self.spider) is None def test_middleware_ignore_http_codes(self): # test response is not cached with self._middleware(HTTPCACHE_IGNORE_HTTP_CODES=[202]) as mw: assert mw.process_request(self.request, self.spider) is None mw.process_response(self.request, self.response, self.spider) assert mw.storage.retrieve_response(self.spider, self.request) is None assert mw.process_request(self.request, self.spider) is None # test response is cached with self._middleware(HTTPCACHE_IGNORE_HTTP_CODES=[203]) as mw: mw.process_response(self.request, self.response, self.spider) response = mw.process_request(self.request, self.spider) assert isinstance(response, HtmlResponse) self.assertEqualResponse(self.response, response) assert 'cached' in response.flags class RFC2616PolicyTest(DefaultStorageTest): policy_class = 'scrapy.extensions.httpcache.RFC2616Policy' def _process_requestresponse(self, mw, request, response): result = None try: result = mw.process_request(request, self.spider) if result: assert isinstance(result, (Request, Response)) return result else: result = mw.process_response(request, response, self.spider) assert isinstance(result, Response) return result except Exception: print('Request', request) print('Response', response) print('Result', result) raise def test_request_cacheability(self): res0 = Response(self.request.url, status=200, headers={'Expires': self.tomorrow}) req0 = Request('http://example.com') req1 = req0.replace(headers={'Cache-Control': 'no-store'}) req2 = req0.replace(headers={'Cache-Control': 'no-cache'}) with self._middleware() as mw: # response for a request with no-store must not be cached res1 = self._process_requestresponse(mw, req1, res0) self.assertEqualResponse(res1, res0) assert mw.storage.retrieve_response(self.spider, req1) is None # Re-do request without no-store and expect it to be cached res2 = self._process_requestresponse(mw, req0, res0) assert 'cached' not in res2.flags res3 = mw.process_request(req0, self.spider) assert 'cached' in res3.flags self.assertEqualResponse(res2, res3) # request with no-cache directive must not return cached response # but it allows new response to be stored res0b = res0.replace(body=b'foo') res4 = self._process_requestresponse(mw, req2, res0b) self.assertEqualResponse(res4, res0b) assert 'cached' not in res4.flags res5 = self._process_requestresponse(mw, req0, None) self.assertEqualResponse(res5, res0b) assert 'cached' in res5.flags def test_response_cacheability(self): responses = [ # 304 is not cacheable no matter what servers sends (False, 304, {}), (False, 304, {'Last-Modified': self.yesterday}), (False, 304, {'Expires': self.tomorrow}), (False, 304, {'Etag': 'bar'}), (False, 304, {'Cache-Control': 'max-age=3600'}), # Always obey no-store cache control (False, 200, {'Cache-Control': 'no-store'}), (False, 200, {'Cache-Control': 'no-store, max-age=300'}), # invalid (False, 200, {'Cache-Control': 'no-store', 'Expires': self.tomorrow}), # invalid # Ignore responses missing expiration and/or validation headers (False, 200, {}), (False, 302, {}), (False, 307, {}), (False, 404, {}), # Cache responses with expiration and/or validation headers (True, 200, {'Last-Modified': self.yesterday}), (True, 203, {'Last-Modified': self.yesterday}), (True, 300, {'Last-Modified': self.yesterday}), (True, 301, {'Last-Modified': self.yesterday}), (True, 308, {'Last-Modified': self.yesterday}), (True, 401, {'Last-Modified': self.yesterday}), (True, 404, {'Cache-Control': 'public, max-age=600'}), (True, 302, {'Expires': self.tomorrow}), (True, 200, {'Etag': 'foo'}), ] with self._middleware() as mw: for idx, (shouldcache, status, headers) in enumerate(responses): req0 = Request('http://example-%d.com' % idx) res0 = Response(req0.url, status=status, headers=headers) res1 = self._process_requestresponse(mw, req0, res0) res304 = res0.replace(status=304) res2 = self._process_requestresponse(mw, req0, res304 if shouldcache else res0) self.assertEqualResponse(res1, res0) self.assertEqualResponse(res2, res0) resc = mw.storage.retrieve_response(self.spider, req0) if shouldcache: self.assertEqualResponse(resc, res1) assert 'cached' in res2.flags and res2.status != 304 else: self.assertFalse(resc) assert 'cached' not in res2.flags # cache unconditionally unless response contains no-store or is a 304 with self._middleware(HTTPCACHE_ALWAYS_STORE=True) as mw: for idx, (_, status, headers) in enumerate(responses): shouldcache = 'no-store' not in headers.get('Cache-Control', '') and status != 304 req0 = Request('http://example2-%d.com' % idx) res0 = Response(req0.url, status=status, headers=headers) res1 = self._process_requestresponse(mw, req0, res0) res304 = res0.replace(status=304) res2 = self._process_requestresponse(mw, req0, res304 if shouldcache else res0) self.assertEqualResponse(res1, res0) self.assertEqualResponse(res2, res0) resc = mw.storage.retrieve_response(self.spider, req0) if shouldcache: self.assertEqualResponse(resc, res1) assert 'cached' in res2.flags and res2.status != 304 else: self.assertFalse(resc) assert 'cached' not in res2.flags def test_cached_and_fresh(self): sampledata = [ (200, {'Date': self.yesterday, 'Expires': self.tomorrow}), (200, {'Date': self.yesterday, 'Cache-Control': 'max-age=86405'}), (200, {'Age': '299', 'Cache-Control': 'max-age=300'}), # Obey max-age if present over any others (200, {'Date': self.today, 'Age': '86405', 'Cache-Control': 'max-age=' + str(86400 * 3), 'Expires': self.yesterday, 'Last-Modified': self.yesterday, }), # obey Expires if max-age is not present (200, {'Date': self.yesterday, 'Age': '86400', 'Cache-Control': 'public', 'Expires': self.tomorrow, 'Last-Modified': self.yesterday, }), # Default missing Date header to right now (200, {'Expires': self.tomorrow}), # Firefox - Expires if age is greater than 10% of (Date - Last-Modified) (200, {'Date': self.today, 'Last-Modified': self.yesterday, 'Age': str(86400 / 10 - 1)}), # Firefox - Set one year maxage to permanent redirects missing expiration info (300, {}), (301, {}), (308, {}), ] with self._middleware() as mw: for idx, (status, headers) in enumerate(sampledata): req0 = Request('http://example-%d.com' % idx) res0 = Response(req0.url, status=status, headers=headers) # cache fresh response res1 = self._process_requestresponse(mw, req0, res0) self.assertEqualResponse(res1, res0) assert 'cached' not in res1.flags # return fresh cached response without network interaction res2 = self._process_requestresponse(mw, req0, None) self.assertEqualResponse(res1, res2) assert 'cached' in res2.flags # validate cached response if request max-age set as 0 req1 = req0.replace(headers={'Cache-Control': 'max-age=0'}) res304 = res0.replace(status=304) assert mw.process_request(req1, self.spider) is None res3 = self._process_requestresponse(mw, req1, res304) self.assertEqualResponse(res1, res3) assert 'cached' in res3.flags def test_cached_and_stale(self): sampledata = [ (200, {'Date': self.today, 'Expires': self.yesterday}), (200, {'Date': self.today, 'Expires': self.yesterday, 'Last-Modified': self.yesterday}), (200, {'Expires': self.yesterday}), (200, {'Expires': self.yesterday, 'ETag': 'foo'}), (200, {'Expires': self.yesterday, 'Last-Modified': self.yesterday}), (200, {'Expires': self.tomorrow, 'Age': '86405'}), (200, {'Cache-Control': 'max-age=86400', 'Age': '86405'}), # no-cache forces expiration, also revalidation if validators exists (200, {'Cache-Control': 'no-cache'}), (200, {'Cache-Control': 'no-cache', 'ETag': 'foo'}), (200, {'Cache-Control': 'no-cache', 'Last-Modified': self.yesterday}), (200, {'Cache-Control': 'no-cache,must-revalidate', 'Last-Modified': self.yesterday}), (200, {'Cache-Control': 'must-revalidate', 'Expires': self.yesterday, 'Last-Modified': self.yesterday}), (200, {'Cache-Control': 'max-age=86400,must-revalidate', 'Age': '86405'}), ] with self._middleware() as mw: for idx, (status, headers) in enumerate(sampledata): req0 = Request('http://example-%d.com' % idx) res0a = Response(req0.url, status=status, headers=headers) # cache expired response res1 = self._process_requestresponse(mw, req0, res0a) self.assertEqualResponse(res1, res0a) assert 'cached' not in res1.flags # Same request but as cached response is stale a new response must # be returned res0b = res0a.replace(body=b'bar') res2 = self._process_requestresponse(mw, req0, res0b) self.assertEqualResponse(res2, res0b) assert 'cached' not in res2.flags cc = headers.get('Cache-Control', '') # Previous response expired too, subsequent request to same # resource must revalidate and succeed on 304 if validators # are present if 'ETag' in headers or 'Last-Modified' in headers: res0c = res0b.replace(status=304) res3 = self._process_requestresponse(mw, req0, res0c) self.assertEqualResponse(res3, res0b) assert 'cached' in res3.flags # get cached response on server errors unless must-revalidate # in cached response res0d = res0b.replace(status=500) res4 = self._process_requestresponse(mw, req0, res0d) if 'must-revalidate' in cc: assert 'cached' not in res4.flags self.assertEqualResponse(res4, res0d) else: assert 'cached' in res4.flags self.assertEqualResponse(res4, res0b) # Requests with max-stale can fetch expired cached responses # unless cached response has must-revalidate req1 = req0.replace(headers={'Cache-Control': 'max-stale'}) res5 = self._process_requestresponse(mw, req1, res0b) self.assertEqualResponse(res5, res0b) if 'no-cache' in cc or 'must-revalidate' in cc: assert 'cached' not in res5.flags else: assert 'cached' in res5.flags def test_process_exception(self): with self._middleware() as mw: res0 = Response(self.request.url, headers={'Expires': self.yesterday}) req0 = Request(self.request.url) self._process_requestresponse(mw, req0, res0) for e in mw.DOWNLOAD_EXCEPTIONS: # Simulate encountering an error on download attempts assert mw.process_request(req0, self.spider) is None res1 = mw.process_exception(req0, e('foo'), self.spider) # Use cached response as recovery assert 'cached' in res1.flags self.assertEqualResponse(res0, res1) # Do not use cached response for unhandled exceptions mw.process_request(req0, self.spider) assert mw.process_exception(req0, Exception('foo'), self.spider) is None def test_ignore_response_cache_controls(self): sampledata = [ (200, {'Date': self.yesterday, 'Expires': self.tomorrow}), (200, {'Date': self.yesterday, 'Cache-Control': 'no-store,max-age=86405'}), (200, {'Age': '299', 'Cache-Control': 'max-age=300,no-cache'}), (300, {'Cache-Control': 'no-cache'}), (200, {'Expires': self.tomorrow, 'Cache-Control': 'no-store'}), ] with self._middleware(HTTPCACHE_IGNORE_RESPONSE_CACHE_CONTROLS=['no-cache', 'no-store']) as mw: for idx, (status, headers) in enumerate(sampledata): req0 = Request('http://example-%d.com' % idx) res0 = Response(req0.url, status=status, headers=headers) # cache fresh response res1 = self._process_requestresponse(mw, req0, res0) self.assertEqualResponse(res1, res0) assert 'cached' not in res1.flags # return fresh cached response without network interaction res2 = self._process_requestresponse(mw, req0, None) self.assertEqualResponse(res1, res2) assert 'cached' in res2.flags if __name__ == '__main__': unittest.main()