94 lines
3.1 KiB
Python
94 lines
3.1 KiB
Python
try:
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import _winreg as winreg
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except ImportError:
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import winreg
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from tzlocal.windows_tz import win_tz
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import pytz
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_cache_tz = None
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def valuestodict(key):
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"""Convert a registry key's values to a dictionary."""
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dict = {}
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size = winreg.QueryInfoKey(key)[1]
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for i in range(size):
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data = winreg.EnumValue(key, i)
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dict[data[0]] = data[1]
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return dict
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def get_localzone_name():
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# Windows is special. It has unique time zone names (in several
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# meanings of the word) available, but unfortunately, they can be
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# translated to the language of the operating system, so we need to
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# do a backwards lookup, by going through all time zones and see which
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# one matches.
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handle = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE)
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TZLOCALKEYNAME = r"SYSTEM\CurrentControlSet\Control\TimeZoneInformation"
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localtz = winreg.OpenKey(handle, TZLOCALKEYNAME)
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keyvalues = valuestodict(localtz)
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localtz.Close()
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if 'TimeZoneKeyName' in keyvalues:
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# Windows 7 (and Vista?)
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# For some reason this returns a string with loads of NUL bytes at
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# least on some systems. I don't know if this is a bug somewhere, I
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# just work around it.
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tzkeyname = keyvalues['TimeZoneKeyName'].split('\x00', 1)[0]
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else:
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# Windows 2000 or XP
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# This is the localized name:
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tzwin = keyvalues['StandardName']
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# Open the list of timezones to look up the real name:
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TZKEYNAME = r"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones"
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tzkey = winreg.OpenKey(handle, TZKEYNAME)
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# Now, match this value to Time Zone information
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tzkeyname = None
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for i in range(winreg.QueryInfoKey(tzkey)[0]):
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subkey = winreg.EnumKey(tzkey, i)
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sub = winreg.OpenKey(tzkey, subkey)
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data = valuestodict(sub)
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sub.Close()
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try:
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if data['Std'] == tzwin:
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tzkeyname = subkey
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break
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except KeyError:
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# This timezone didn't have proper configuration.
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# Ignore it.
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pass
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tzkey.Close()
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handle.Close()
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if tzkeyname is None:
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raise LookupError('Can not find Windows timezone configuration')
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timezone = win_tz.get(tzkeyname)
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if timezone is None:
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# Nope, that didn't work. Try adding "Standard Time",
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# it seems to work a lot of times:
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timezone = win_tz.get(tzkeyname + " Standard Time")
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# Return what we have.
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if timezone is None:
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raise pytz.UnknownTimeZoneError('Can not find timezone ' + tzkeyname)
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return timezone
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def get_localzone():
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"""Returns the zoneinfo-based tzinfo object that matches the Windows-configured timezone."""
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global _cache_tz
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if _cache_tz is None:
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_cache_tz = pytz.timezone(get_localzone_name())
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return _cache_tz
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def reload_localzone():
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"""Reload the cached localzone. You need to call this if the timezone has changed."""
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global _cache_tz
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_cache_tz = pytz.timezone(get_localzone_name())
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