codekingpro/portable-devtools

1"""2Timezone utility functions.3"""4 5# Copyright (C) 2020 The Psycopg Team6 7import logging8from typing import Dict, Optional, Union9from datetime import timezone, tzinfo10 11from .pq.abc import PGconn12from ._compat import ZoneInfo13 14logger = logging.getLogger("psycopg")15 16_timezones: Dict[Union[None, bytes], tzinfo] = {17    None: timezone.utc,18    b"UTC": timezone.utc,19}20 21 22def get_tzinfo(pgconn: Optional[PGconn]) -> tzinfo:23    """Return the Python timezone info of the connection's timezone."""24    tzname = pgconn.parameter_status(b"TimeZone") if pgconn else None25    try:26        return _timezones[tzname]27    except KeyError:28        sname = tzname.decode() if tzname else "UTC"29        try:30            zi: tzinfo = ZoneInfo(sname)31        except (KeyError, OSError):32            logger.warning("unknown PostgreSQL timezone: %r; will use UTC", sname)33            zi = timezone.utc34        except Exception as ex:35            logger.warning(36                "error handling PostgreSQL timezone: %r; will use UTC (%s - %s)",37                sname,38                type(ex).__name__,39                ex,40            )41            zi = timezone.utc42 43        _timezones[tzname] = zi44        return zi45