d65e1b5245
same issue as discussed here https://memex.zulipchat.com/#narrow/stream/279610-data/topic/google.20takeout.20timestamps also see corresponding changes for google_takeout_parser - https://github.com/seanbreckenridge/google_takeout_parser/pull/28/files - https://github.com/seanbreckenridge/google_takeout_parser/pull/30/files
77 lines
2.5 KiB
Python
77 lines
2.5 KiB
Python
from functools import lru_cache
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from typing import Sequence, Dict
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import pytz
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from .common import datetime_aware, datetime_naive
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def user_forced() -> Sequence[str]:
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# conversion from abbreviations is always ambiguous
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# https://stackoverflow.com/questions/36067621/python-all-possible-timezone-abbreviations-for-given-timezone-name-and-vise-ve
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try:
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from my.config import time as user_config
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return user_config.tz.force_abbreviations # type: ignore[attr-defined]
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except:
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# todo log/apply policy
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return []
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@lru_cache(1)
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def _abbr_to_timezone_map() -> Dict[str, pytz.BaseTzInfo]:
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# also force UTC to always correspond to utc
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# this makes more sense than Zulu it ends up by default
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timezones = pytz.all_timezones + ['UTC'] + list(user_forced())
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res: Dict[str, pytz.BaseTzInfo] = {}
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for tzname in timezones:
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tz = pytz.timezone(tzname)
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infos = getattr(tz, '_tzinfos', []) # not sure if can rely on attr always present?
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for info in infos:
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abbr = info[-1]
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# todo could support this with a better error handling strategy?
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# otz = res.get(abbr, tz)
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# if otz != tz:
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# raise RuntimeError(abbr, tz, otz)
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res[abbr] = tz
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# ugh. also necessary, e.g. for Zulu?? why is it not in _tzinfos?
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# note: somehow this is not the same as the tzname!
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tzn = getattr(tz, '_tzname', None)
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if tzn is not None:
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res[tzn] = tz
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return res
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@lru_cache(maxsize=None)
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def abbr_to_timezone(abbr: str) -> pytz.BaseTzInfo:
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return _abbr_to_timezone_map()[abbr]
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def localize_with_abbr(dt: datetime_naive, *, abbr: str) -> datetime_aware:
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if abbr.lower() == 'utc':
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# best to shortcut here to avoid complications
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return pytz.utc.localize(dt)
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tz = abbr_to_timezone(abbr)
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# this will compute the correct UTC offset
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tzinfo = tz.localize(dt).tzinfo
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assert tzinfo is not None # make mypy happy
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return tz.normalize(dt.replace(tzinfo=tzinfo))
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def zone_to_countrycode(zone: str) -> str:
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# todo make optional?
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return _zones_to_countrycode()[zone]
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@lru_cache(1)
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def _zones_to_countrycode():
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# https://stackoverflow.com/a/13020785/706389
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res = {}
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for countrycode, timezones in pytz.country_timezones.items():
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for timezone in timezones:
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res[timezone] = countrycode
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return res
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# todo stuff here could be a bit more defensive? e.g. dependent on policy
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