Convert timestamps to UTC at the boundary

Эта статья ещё не доступна на языке «Русский»; показан оригинал.

methodology · en · актуально на 2026-09-21 · изменено 2026-09-23, ревизия 3 · reviewed (рецензия задокументирована 2026-09-23)

Reject ambiguous timestamps, convert aware instants to UTC and preserve the original timezone when local scheduling semantics matter.

Distinguish an instant from a local appointment

A timestamp with an offset identifies an instant. A local time without an offset needs an agreed timezone and potentially a daylight-saving ambiguity policy. Python datetime distinguishes aware and naive objects; do not silently interpret naive input using the server's local timezone.

Example for offset-bearing input

from datetime import datetime, timezone

def as_utc(text):
    value = datetime.fromisoformat(text)
    if value.tzinfo is None or value.utcoffset() is None:
        raise ValueError("explicit offset required")
    return value.astimezone(timezone.utc)

assert as_utc("2026-09-21T14:00:00+02:00").hour == 12

Acceptance and limits

Test positive and negative offsets, a UTC input and rejection of a naive value. Keep precision and accepted input syntax in the API contract. For “every day at 09:00 in Zurich”, retain the named timezone and scheduling rule; converting one occurrence to UTC does not define all future occurrences.

UTC is appropriate for comparing instants and recording events. Use an elapsed-time clock for local durations and timeouts, rather than subtracting wall-clock timestamps that may be adjusted.

Область и основание

Original worked method and proposed acceptance fixtures; no empirical performance result is claimed. The cited primary documentation was read for the specific technical behavior described.

Актуально на: 2026-09-21. Статус: reviewed — правки сбрасывают статус рецензии. Считайте текст непроверенным справочным материалом и сверяйтесь с источниками.

Источники

Рецензия

Задокументированная рецензия ревизии 3 аккаунтом редактора 344519e7-8ea1-44c6-abaa-29102abda2b6 от 2026-09-23. Относится к текущей ревизии: да.

Operator review: article written by an account of the operator (MK Groups Schweiz) and accepted as reviewed by the operator.

Operator decision of 2026-09-23 that the operator's own curated articles count as reviewed; each cited source was fetched at import time and the quoted phrase was found on the page. No independent third-party review is claimed.

Задокументированная рецензия фиксирует, что было проверено; она не гарантирует истинность.

Атрибуция и лицензия

Последнее изменение: Replaced generic draft with a specific procedure, example, failure cases and correctly scoped sources; removed unrelated product applicability.

Оригинальный материал: CC BY 4.0. Материалы по ссылкам сохраняют собственные права.