/usr/lib/python2.7/dist-packages/ubuntu-kylin-sso-client/ubuntu_kylin_sso/utils/webclient/timestamp.py is in python-ubuntu-kylin-sso-client 0.1.2.5.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 | # -*- coding: utf-8 -*-
#
# Copyright 2011-2013 Canonical Ltd.
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License version 3, as published
# by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranties of
# MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
# PURPOSE. See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
#
# In addition, as a special exception, the copyright holders give
# permission to link the code of portions of this program with the
# OpenSSL library under certain conditions as described in each
# individual source file, and distribute linked combinations
# including the two.
# You must obey the GNU General Public License in all respects
# for all of the code used other than OpenSSL. If you modify
# file(s) with this exception, you may extend this exception to your
# version of the file(s), but you are not obligated to do so. If you
# do not wish to do so, delete this exception statement from your
# version. If you delete this exception statement from all source
# files in the program, then also delete it here.
"""Timestamp synchronization with the server."""
import time
from twisted.internet import defer
from ubuntu_kylin_sso import SSO_AUTH_BASE_URL
from ubuntu_kylin_sso.logger import setup_logging
logger = setup_logging("ubuntu_kylin_sso.utils.webclient.timestamp")
NOCACHE_HEADERS = {"Cache-Control": "no-cache"}
class TimestampChecker(object):
"""A timestamp that's regularly checked with a server."""
CHECKING_INTERVAL = 60 * 60 # in seconds
ERROR_INTERVAL = 30 # in seconds
SERVER_IRI = SSO_AUTH_BASE_URL
def __init__(self, webclient_class):
"""Initialize this instance."""
self.next_check = time.time()
self.skew = 0
self.webclient_class = webclient_class
@defer.inlineCallbacks
def get_server_date_header(self, server_iri):
"""Get the server date using twisted webclient."""
webclient = self.webclient_class()
try:
response = yield webclient.request(server_iri, method="HEAD",
extra_headers=NOCACHE_HEADERS)
defer.returnValue(response.headers["Date"][0])
finally:
webclient.shutdown()
@defer.inlineCallbacks
def get_server_time(self):
"""Get the time at the server."""
date_string = yield self.get_server_date_header(self.SERVER_IRI)
# delay import, otherwise a default reactor gets installed
from twisted.web import http
timestamp = http.stringToDatetime(date_string)
defer.returnValue(timestamp)
@defer.inlineCallbacks
def get_faithful_time(self):
"""Get an accurate timestamp."""
local_time = time.time()
if local_time >= self.next_check:
try:
server_time = yield self.get_server_time()
self.next_check = local_time + self.CHECKING_INTERVAL
self.skew = server_time - local_time
logger.debug("Calculated server time skew: %r", self.skew)
# We just log all exceptions while trying to get the server time
# pylint: disable=W0703
except Exception as e:
logger.debug("Error while verifying server time skew: %r", e)
self.next_check = local_time + self.ERROR_INTERVAL
# delay import, otherwise a default reactor gets installed
from twisted.web import http
logger.debug("Using corrected timestamp: %r",
http.datetimeToString(local_time + self.skew))
defer.returnValue(int(local_time + self.skew))
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