From a69789fa0650f2975508b6f8f572f8bc8ffdb078 Mon Sep 17 00:00:00 2001 From: Samuel Merritt Date: Mon, 3 Mar 2014 11:25:43 -0800 Subject: [PATCH] Allow pre-1970 dates in If-[Un]Modified-Since If I want to fetch an object only if it is newer than the first moon landing, I send a GET request with header: If-Modified-Since: Sun, 20 Jul 1969 20:18:00 UTC Since that date is older than Swift, I expect a 2xx response. However, I get a 412, which isn't even a valid thing to do for If-Modified-Since; it should either be 2xx or 304. This is because of two problems: (a) Swift treats pre-1970 dates as invalid, and (b) Swift returns 412 when a date is invalid instead of ignoring it. This commit makes it so any time between datetime.datetime.min and datetime.datetime.max is an acceptable value for If-Modified-Since and If-Unmodified-Since. Dates outside that date range are treated as invalid headers and thus are ignored, as RFC 2616 section 14.28 requires ("If the specified date is invalid, the header is ignored"). This only works for dates that the Python standard library can parse, which on my machine is 01 Jan 1 to 31 Dec 9999. Eliminating those restrictions would require implementing our own date parsing and comparison, and that's almost certainly not worth it. Change-Id: I4cb4903c4e5e3b6b3c9506c2cabbfbda62e82f35 --- swift/common/swob.py | 5 +---- swift/obj/server.py | 15 +++++---------- test/unit/common/test_swob.py | 12 +++++++++--- test/unit/obj/test_server.py | 17 +++++++++-------- 4 files changed, 24 insertions(+), 25 deletions(-) diff --git a/swift/common/swob.py b/swift/common/swob.py index ba3b54bb7c..638086ea0e 100644 --- a/swift/common/swob.py +++ b/swift/common/swob.py @@ -138,12 +138,9 @@ def _datetime_property(header): if value is not None: try: parts = parsedate(self.headers[header])[:7] - date = datetime(*(parts + (UTC,))) + return datetime(*(parts + (UTC,))) except Exception: return None - if date.year < 1970: - raise ValueError('Somehow an invalid year') - return date def setter(self, value): if isinstance(value, (float, int, long)): diff --git a/swift/obj/server.py b/swift/obj/server.py index 3436b632c9..a4d8de7c93 100644 --- a/swift/obj/server.py +++ b/swift/obj/server.py @@ -481,21 +481,16 @@ class ObjectController(object): obj_size = int(metadata['Content-Length']) file_x_ts = metadata['X-Timestamp'] file_x_ts_flt = float(file_x_ts) - try: - if_unmodified_since = request.if_unmodified_since - except (OverflowError, ValueError): - # catches timestamps before the epoch - return HTTPPreconditionFailed(request=request) file_x_ts_utc = datetime.fromtimestamp(file_x_ts_flt, UTC) + + if_unmodified_since = request.if_unmodified_since if if_unmodified_since and file_x_ts_utc > if_unmodified_since: return HTTPPreconditionFailed(request=request) - try: - if_modified_since = request.if_modified_since - except (OverflowError, ValueError): - # catches timestamps before the epoch - return HTTPPreconditionFailed(request=request) + + if_modified_since = request.if_modified_since if if_modified_since and file_x_ts_utc <= if_modified_since: return HTTPNotModified(request=request) + keep_cache = (self.keep_cache_private or ('X-Auth-Token' not in request.headers and 'X-Storage-Token' not in request.headers)) diff --git a/test/unit/common/test_swob.py b/test/unit/common/test_swob.py index a2e5387047..7cc5439e91 100644 --- a/test/unit/common/test_swob.py +++ b/test/unit/common/test_swob.py @@ -18,6 +18,7 @@ import unittest import datetime import re +import time from StringIO import StringIO from urllib import quote @@ -644,13 +645,18 @@ class TestRequest(unittest.TestCase): self.assertEquals(req.headers['If-Unmodified-Since'], 'something') self.assertEquals(req.if_unmodified_since, None) - req.if_unmodified_since = -1 - self.assertRaises(ValueError, lambda: req.if_unmodified_since) - self.assert_('If-Unmodified-Since' in req.headers) req.if_unmodified_since = None self.assert_('If-Unmodified-Since' not in req.headers) + too_big_date_list = list(datetime.datetime.max.timetuple()) + too_big_date_list[0] += 1 # bump up the year + too_big_date = time.strftime( + "%a, %d %b %Y %H:%M:%S UTC", time.struct_time(too_big_date_list)) + + req.if_unmodified_since = too_big_date + self.assertEqual(req.if_unmodified_since, None) + def test_bad_range(self): req = swift.common.swob.Request.blank('/hi/there', body='hi') req.range = 'bad range' diff --git a/test/unit/obj/test_server.py b/test/unit/obj/test_server.py index 59555073a5..749c9705ec 100755 --- a/test/unit/obj/test_server.py +++ b/test/unit/obj/test_server.py @@ -17,6 +17,7 @@ """Tests for swift.obj.server""" import cPickle as pickle +import datetime import operator import os import mock @@ -24,7 +25,7 @@ import unittest import math from shutil import rmtree from StringIO import StringIO -from time import gmtime, strftime, time +from time import gmtime, strftime, time, struct_time from tempfile import mkdtemp from hashlib import md5 @@ -1911,16 +1912,16 @@ class TestObjectController(unittest.TestCase): headers={'If-Modified-Since': 'Not a valid date'}) resp = req.get_response(self.object_controller) self.assertEquals(resp.status_int, 200) + + too_big_date_list = list(datetime.datetime.max.timetuple()) + too_big_date_list[0] += 1 # bump up the year + too_big_date = strftime( + "%a, %d %b %Y %H:%M:%S UTC", struct_time(too_big_date_list)) req = Request.blank( '/sda1/p/a/c/o', environ={'REQUEST_METHOD': 'GET'}, - headers={'If-Unmodified-Since': 'Sat, 29 Oct 1000 19:43:31 GMT'}) + headers={'If-Unmodified-Since': too_big_date}) resp = req.get_response(self.object_controller) - self.assertEquals(resp.status_int, 412) - req = Request.blank( - '/sda1/p/a/c/o', environ={'REQUEST_METHOD': 'GET'}, - headers={'If-Modified-Since': 'Sat, 29 Oct 1000 19:43:31 GMT'}) - resp = req.get_response(self.object_controller) - self.assertEquals(resp.status_int, 412) + self.assertEquals(resp.status_int, 200) def test_content_encoding(self): req = Request.blank(