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"""Fill gaps in Python time API-s.
parse_iso_timestamp:
Parse reasonable subset of ISO_8601 timestamp formats.
[ http://en.wikipedia.org/wiki/ISO_8601 ]
datetime_to_timestamp:
Get POSIX timestamp from datetime() object.
"""
import re
import time
from datetime import datetime, timedelta, tzinfo
__all__ = ['parse_iso_timestamp', 'FixedOffsetTimezone', 'datetime_to_timestamp']
try:
timedelta.total_seconds # new in 2.7
except AttributeError:
def total_seconds(td):
return float (td.microseconds + (td.seconds + td.days * 24 * 3600) * 10**6) / 10**6
import ctypes
_get_dict = ctypes.pythonapi._PyObject_GetDictPtr
_get_dict.restype = ctypes.POINTER(ctypes.py_object)
_get_dict.argtypes = [ctypes.py_object]
d = _get_dict(timedelta)[0]
d['total_seconds'] = total_seconds
class FixedOffsetTimezone(tzinfo):
"""Fixed offset in minutes east from UTC."""
__slots__ = ('__offset', '__name')
def __init__(self, offset):
self.__offset = timedelta(minutes = offset)
# numeric tz name
h, m = divmod(abs(offset), 60)
if offset < 0:
h = -h
if m:
self.__name = "%+03d:%02d" % (h,m)
else:
self.__name = "%+03d" % h
def utcoffset(self, dt):
return self.__offset
def tzname(self, dt):
return self.__name
def dst(self, dt):
return ZERO
ZERO = timedelta(0)
#
# Parse ISO_8601 timestamps.
#
"""
TODO:
- support more combinations from ISO 8601 (only reasonable ones)
- cache TZ objects
- make it faster?
"""
_iso_regex = r"""
\s*
(?P<year> \d\d\d\d) [-] (?P<month> \d\d) [-] (?P<day> \d\d) [ T]
(?P<hour> \d\d) [:] (?P<min> \d\d)
(?: [:] (?P<sec> \d\d ) (?: [.,] (?P<ss> \d+))? )?
(?: \s* (?P<tzsign> [-+]) (?P<tzhr> \d\d) (?: [:]? (?P<tzmin> \d\d))?
| (?P<tzname> Z ) )?
\s* $
"""
_iso_rc = None
def parse_iso_timestamp(s, default_tz = None):
"""Parse ISO timestamp to datetime object.
YYYY-MM-DD[ T]HH:MM[:SS[.ss]][-+HH[:MM]]
Assumes that second fractions are zero-trimmed from the end,
so '.15' means 150000 microseconds.
If the timezone offset is not present, use default_tz as tzinfo.
By default its None, meaning the datetime object will be without tz.
Only fixed offset timezones are supported.
>>> str(parse_iso_timestamp('2005-06-01 15:00'))
'2005-06-01 15:00:00'
>>> str(parse_iso_timestamp(' 2005-06-01T15:00 +02 '))
'2005-06-01 15:00:00+02:00'
>>> str(parse_iso_timestamp('2005-06-01 15:00:33+02:00'))
'2005-06-01 15:00:33+02:00'
>>> d = parse_iso_timestamp('2005-06-01 15:00:59.33 +02')
>>> d.strftime("%z %Z")
'+0200 +02'
>>> str(parse_iso_timestamp(str(d)))
'2005-06-01 15:00:59.330000+02:00'
>>> parse_iso_timestamp('2005-06-01 15:00-0530').strftime('%Y-%m-%d %H:%M %z %Z')
'2005-06-01 15:00 -0530 -05:30'
>>> parse_iso_timestamp('2014-10-27T11:59:13Z').strftime('%Y-%m-%d %H:%M:%S %z %Z')
'2014-10-27 11:59:13 +0000 +00'
"""
global _iso_rc
if _iso_rc is None:
_iso_rc = re.compile(_iso_regex, re.X)
m = _iso_rc.match(s)
if not m:
raise ValueError('Date not in ISO format: %s' % repr(s))
tz = default_tz
if m.group('tzsign'):
tzofs = int(m.group('tzhr')) * 60
if m.group('tzmin'):
tzofs += int(m.group('tzmin'))
if m.group('tzsign') == '-':
tzofs = -tzofs
tz = FixedOffsetTimezone(tzofs)
elif m.group('tzname'):
tz = UTC
return datetime(int(m.group('year')),
int(m.group('month')),
int(m.group('day')),
int(m.group('hour')),
int(m.group('min')),
m.group('sec') and int(m.group('sec')) or 0,
m.group('ss') and int(m.group('ss').ljust(6, '0')) or 0,
tz)
#
# POSIX timestamp from datetime()
#
UTC = FixedOffsetTimezone(0)
TZ_EPOCH = datetime.fromtimestamp(0, UTC)
UTC_NOTZ_EPOCH = datetime.utcfromtimestamp(0)
def datetime_to_timestamp(dt, local_time=True):
"""Get posix timestamp from datetime() object.
if dt is without timezone, then local_time specifies
whether it's UTC or local time.
Returns seconds since epoch as float.
>>> datetime_to_timestamp(parse_iso_timestamp("2005-06-01 15:00:59.5 +02"))
1117630859.5
>>> datetime_to_timestamp(datetime.fromtimestamp(1117630859.5, UTC))
1117630859.5
>>> datetime_to_timestamp(datetime.fromtimestamp(1117630859.5))
1117630859.5
>>> now = datetime.utcnow()
>>> now2 = datetime.utcfromtimestamp(datetime_to_timestamp(now, False))
>>> abs(now2.microsecond - now.microsecond) < 100
True
>>> now2 = now2.replace(microsecond = now.microsecond)
>>> now == now2
True
>>> now = datetime.now()
>>> now2 = datetime.fromtimestamp(datetime_to_timestamp(now))
>>> abs(now2.microsecond - now.microsecond) < 100
True
>>> now2 = now2.replace(microsecond = now.microsecond)
>>> now == now2
True
"""
if dt.tzinfo:
delta = dt - TZ_EPOCH
return delta.total_seconds()
elif local_time:
s = time.mktime(dt.timetuple())
return s + (dt.microsecond / 1000000.0)
else:
delta = dt - UTC_NOTZ_EPOCH
return delta.total_seconds()
if __name__ == '__main__':
import doctest
doctest.testmod()
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