116 lines
2.9 KiB
Python
116 lines
2.9 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2025 Mike Fährmann
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License version 2 as
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# published by the Free Software Foundation.
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"""Date/Time utilities"""
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import sys
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import time
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from datetime import datetime, date, timedelta, timezone # noqa F401
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class NullDatetime(datetime):
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def __bool__(self):
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return False
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def __str__(self):
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return "[Invalid DateTime]"
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def __format__(self, format_spec):
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return f"[Invalid DateTime {format_spec}]"
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NONE = NullDatetime(1, 1, 1)
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EPOCH = datetime(1970, 1, 1)
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SECOND = timedelta(0, 1)
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def normalize(dt):
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# if (o := dt.utcoffset()) is not None:
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# return dt.replace(tzinfo=None, microsecond=0) - o
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if dt.tzinfo is not None:
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return dt.astimezone(timezone.utc).replace(tzinfo=None, microsecond=0)
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if dt.microsecond:
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return dt.replace(microsecond=0)
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return dt
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def convert(value):
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"""Convert 'value' to a naive UTC datetime object"""
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if not value:
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return NONE
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if isinstance(value, datetime):
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return normalize(value)
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if isinstance(value, str) and (dt := parse_iso(value)) is not NONE:
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return dt
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return parse_ts(value)
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def parse(dt_string, format):
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"""Parse 'dt_string' according to 'format'"""
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try:
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return normalize(datetime.strptime(dt_string, format))
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except Exception:
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return NONE
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if sys.hexversion < 0x30c0000:
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# Python <= 3.11
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def parse_iso(dt_string):
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"""Parse 'dt_string' as ISO 8601 value"""
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try:
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if dt_string[-1] == "Z":
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# compat for Python < 3.11
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dt_string = dt_string[:-1]
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elif dt_string[-5] in "+-":
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# compat for Python < 3.11
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dt_string = f"{dt_string[:-2]}:{dt_string[-2:]}"
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return normalize(datetime.fromisoformat(dt_string))
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except Exception:
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return NONE
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from_ts = datetime.utcfromtimestamp
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now = datetime.utcnow
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else:
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# Python >= 3.12
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def parse_iso(dt_string):
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"""Parse 'dt_string' as ISO 8601 value"""
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try:
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return normalize(datetime.fromisoformat(dt_string))
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except Exception:
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return NONE
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def from_ts(ts=None):
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"""Convert Unix timestamp to naive UTC datetime"""
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Y, m, d, H, M, S, _, _, _ = time.gmtime(ts)
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return datetime(Y, m, d, H, M, S)
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now = from_ts
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def parse_ts(ts, default=NONE):
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"""Create a datetime object from a Unix timestamp"""
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try:
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return from_ts(int(ts))
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except Exception:
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return default
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def to_ts(dt):
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"""Convert naive UTC datetime to Unix timestamp"""
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return (dt - EPOCH) / SECOND
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def to_ts_string(dt):
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"""Convert naive UTC datetime to Unix timestamp string"""
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try:
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return str((dt - EPOCH) // SECOND)
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except Exception:
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return ""
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