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# friends-service -- send & receive messages from any social network
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# Copyright (C) 2012 Canonical Ltd
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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 as published by
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# the Free Software Foundation, version 3 of the License.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from calendar import timegm
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from contextlib import contextmanager
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from datetime import datetime, timedelta
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# Date time formats. Assume no microseconds and no timezone.
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ISO8601_FORMAT = '%Y-%m-%dT%H:%M:%S'
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TWITTER_FORMAT = '%a %b %d %H:%M:%S %Y'
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IDENTICA_FORMAT = '%a, %d %b %Y %H:%M:%S'
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locale.setlocale(locale.LC_TIME, 'C')
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locale.setlocale(locale.LC_TIME, '')
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return datetime.strptime(t, ISO8601_FORMAT)
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def _from_iso8601alt(t):
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return datetime.strptime(t, ISO8601_FORMAT.replace('T', ' '))
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return datetime.strptime(t, TWITTER_FORMAT)
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def _from_identica(t):
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return datetime.strptime(t, IDENTICA_FORMAT)
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def _fromutctimestamp(t):
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return datetime.utcfromtimestamp(float(t))
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PARSERS = (_from_iso8601, _from_iso8601alt, _from_twitter,
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_from_identica, _fromutctimestamp)
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"""Parse an ISO 8601 datetime string and return seconds since epoch.
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This accepts either a naive (i.e. timezone-less) string or a timezone
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aware string. The timezone must start with a + or - and must be followed
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by exactly four digits. This string is parsed and converted to UTC. This
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value is then converted to an integer seconds since epoch.
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# In Python 3.2, strptime() is implemented in Python, so in order to
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# parse the UTC timezone (e.g. +0000), you'd think we could just
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# append %z on the format. We can't rely on it though because of the
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# non-ISO 8601 formats that some APIs use (I'm looking at you Twitter
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# and Facebook). We'll use a regular expression to tear out the
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# timezone string and do the conversion ourselves.
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def capture_tz(match_object):
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tz_string = match_object.group('tz')
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if tz_string is not None:
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# It's possible that we'll see more than one substring
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# matching the timezone pattern. It should be highly unlikely
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# so we won't test for that here, at least not now.
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# The tz_offset is positive, so it must be subtracted from the
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# naive datetime in order to return it to UTC. E.g.
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# 13:00 -0400 is 17:00 +0000
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# 1300 - (-0400 / 100)
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if tz_offset is not None:
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# This is not the first time we're seeing a timezone.
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raise ValueError('Unsupported time string: {0}'.format(t))
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tz_offset = timedelta(hours=int(tz_string) / 100)
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# Return the empty string so as to remove the timezone pattern
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# from the string we're going to parse.
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# Parse the time string, calling capture_tz() for each timezone match
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# group we find. The callback itself will ensure we see no more
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# than one timezone string.
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naive_t = re.sub(r'[ ]*(?P<tz>[-+]\d{4})', capture_tz, t)
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if tz_offset is None:
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# No timezone string was found.
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tz_offset = timedelta()
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for parser in PARSERS:
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parsed_dt = parser(naive_t)
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raise ValueError('Unsupported time string: {0}'.format(t))
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# We must have gotten a valid datetime. Normalize out the timezone
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# offset and convert it to Epoch seconds. Use timegm() to give us
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# UTC-based conversion from a struct_time to seconds-since-epoch.
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utc_dt = parsed_dt - tz_offset
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timetup = utc_dt.timetuple()
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return int(timegm(timetup))
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def iso8601utc(timestamp, timezone_offset=0, sep='T'):
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"""Convert from a Unix epoch timestamp to an ISO 8601 date time string.
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:param timestamp: Unix epoch timestamp in seconds.
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:type timestamp: float
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:param timezone_offset: Offset in hours*100 east/west of UTC. E.g. -400
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means 4 hours west of UTC; 130 means 1.5 hours east of UTC.
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:type timezone_offset: int
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:param sep: ISO 8601 separator placed between the date and time portions
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:type sep: string of length 1.
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:return: ISO 8601 datetime string.
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dt = datetime.utcfromtimestamp(timestamp)
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hours_east, minutes_east = divmod(timezone_offset, 100)
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correction = timedelta(hours=hours_east, minutes=minutes_east)
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# Subtract the correction to move closer to UTC, since the offset is
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# positive when east of UTC and negative when west of UTC.
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return (dt - correction).isoformat(sep=sep)
added
removed
friends/utils/time.py
