aurweb/aurweb/time.py
2022-08-22 22:40:45 +02:00

89 lines
2.5 KiB
Python

import zoneinfo
from collections import OrderedDict
from datetime import datetime
from urllib.parse import unquote
from zoneinfo import ZoneInfo
from fastapi import Request
import aurweb.config
def tz_offset(name: str):
"""Get a timezone offset in the form "+00:00" by its name.
Example: tz_offset('America/Los_Angeles')
:param name: Timezone name
:return: UTC offset in the form "+00:00"
"""
dt = datetime.now(tz=zoneinfo.ZoneInfo(name))
# Our offset in hours.
offset = dt.utcoffset().total_seconds() / 60 / 60
# Prefix the offset string with a - or +.
offset_string = "-" if offset < 0 else "+"
# Remove any negativity from the offset. We want a good offset. :)
offset = abs(offset)
# Truncate the floating point digits, giving the hours.
hours = int(offset)
# Subtract hours from the offset, and multiply the remaining fraction
# (0 - 0.99[repeated]) with 60 minutes to get the number of minutes
# remaining in the hour.
minutes = int((offset - hours) * 60)
# Pad the hours and minutes by two places.
offset_string += "{:0>2}:{:0>2}".format(hours, minutes)
return offset_string
SUPPORTED_TIMEZONES = OrderedDict(
{
# Flatten out the list of tuples into an OrderedDict.
timezone: offset
for timezone, offset in sorted(
[
# Comprehend a list of tuples (timezone, offset display string)
# and sort them by (offset, timezone).
(tz, "(UTC%s) %s" % (tz_offset(tz), tz))
for tz in zoneinfo.available_timezones()
],
key=lambda element: (tz_offset(element[0]), element[0]),
)
}
)
def get_request_timezone(request: Request):
"""Get a request's timezone by its AURTZ cookie. We use the
configuration's [options] default_timezone otherwise.
@param request FastAPI request
"""
default_tz = aurweb.config.get("options", "default_timezone")
if request.user.is_authenticated():
default_tz = request.user.Timezone
return unquote(request.cookies.get("AURTZ", default_tz))
def now(timezone: str) -> datetime:
"""
Get the current timezone-localized timestamp.
:param timezone: Valid timezone supported by ZoneInfo
:return: Current localized datetime
"""
return datetime.now(tz=ZoneInfo(timezone))
def utcnow() -> int:
"""
Get the current UTC timestamp.
:return: Current UTC timestamp
"""
return int(datetime.utcnow().timestamp())