63 lines
2.2 KiB
Python
63 lines
2.2 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2018 Google Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Provides a tzinfo subclass to represent the UTC timezone."""
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from __future__ import absolute_import
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from __future__ import print_function
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from __future__ import division
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from __future__ import unicode_literals
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from datetime import timedelta
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from datetime import tzinfo
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class UTC(tzinfo):
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"""Timezone information class used to convert datetime timestamps to UTC.
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This class is necessary to convert timestamps to UTC. By default Python
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datetime objects are timezone unaware. This created problems when interacting
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with cloud object timestamps which are timezone-aware. This issue appeared
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when handling the timeCreated metadata attribute; the values returned by the
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service were placed in RFC 3339 format in the storage_v1_messages module. RFC
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3339 requires a timezone in any timestamp. This caused problems as the
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datetime object elsewhere in the code was timezone unaware and was different
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by exactly one hour. The main problem was that the local system used daylight
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savings time which adjusted the timestamp ahead by one hour.
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"""
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def utcoffset(self, _):
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"""An offset of the number of minutes away from UTC this tzinfo object is.
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Returns:
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A time duration of zero. UTC is zero minutes away from UTC.
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"""
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return timedelta(0)
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def tzname(self, _):
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"""A method to retrieve the name of this timezone object.
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Returns:
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The name of the timezone (i.e. 'UTC').
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"""
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return 'UTC'
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def dst(self, _):
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"""A fixed offset to handle daylight savings time (DST).
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Returns:
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A time duration of zero as UTC does not use DST.
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"""
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return timedelta(0)
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