mediagoblin/tools/timesince.py

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  28
  29 from __future__ import unicode_literals
  30
  31 import datetime
  32 import pytz
  33
  34 from mediagoblin.tools.translate import pass_to_ugettext, lazy_pass_to_ungettext as _
  35
  36 """UTC time zone as a tzinfo instance."""
  37 utc = pytz.utc if pytz else UTC()
  38
  39 def is_aware(value):
  40     """
  41     Determines if a given datetime.datetime is aware.
  42
  43     The logic is described in Python's docs:
  44     http://docs.python.org/library/datetime.html#datetime.tzinfo
  45     """
  46     return value.tzinfo is not None and value.tzinfo.utcoffset(value) is not None
  47
  48 def timesince(d, now=None, reversed=False):
  49     """
  50     Takes two datetime objects and returns the time between d and now
  51     as a nicely formatted string, e.g. "10 minutes".  If d occurs after now,
  52     then "0 minutes" is returned.
  53
  54     Units used are years, months, weeks, days, hours, and minutes.
  55     Seconds and microseconds are ignored.  Up to two adjacent units will be
  56     displayed.  For example, "2 weeks, 3 days" and "1 year, 3 months" are
  57     possible outputs, but "2 weeks, 3 hours" and "1 year, 5 days" are not.
  58
  59     Adapted from http://blog.natbat.co.uk/archive/2003/Jun/14/time_since
  60     """
  61     chunks = (
  62       (60 * 60 * 24 * 365, lambda n: _('year', 'years', n)),
  63       (60 * 60 * 24 * 30, lambda n: _('month', 'months', n)),
  64       (60 * 60 * 24 * 7, lambda n : _('week', 'weeks', n)),
  65       (60 * 60 * 24, lambda n : _('day', 'days', n)),
  66       (60 * 60, lambda n: _('hour', 'hours', n)),
  67       (60, lambda n: _('minute', 'minutes', n))
  68     )
  69     # Convert datetime.date to datetime.datetime for comparison.
  70     if not isinstance(d, datetime.datetime):
  71         d = datetime.datetime(d.year, d.month, d.day)
  72     if now and not isinstance(now, datetime.datetime):
  73         now = datetime.datetime(now.year, now.month, now.day)
  74
  75     if not now:
  76         now = datetime.datetime.now(utc if is_aware(d) else None)
  77
  78     delta = (d - now) if reversed else (now - d)
  79     # ignore microseconds
  80     since = delta.days * 24 * 60 * 60 + delta.seconds
  81     if since <= 0:
  82         # d is in the future compared to now, stop processing.
  83         return '0 ' + pass_to_ugettext('minutes')
  84     for i, (seconds, name) in enumerate(chunks):
  85         count = since // seconds
  86         if count != 0:
  87             break
  88     s = pass_to_ugettext('%(number)d %(type)s') % {'number': count, 'type': name(count)}
  89     if i + 1 < len(chunks):
  90         # Now get the second item
  91         seconds2, name2 = chunks[i + 1]
  92         count2 = (since - (seconds * count)) // seconds2
  93         if count2 != 0:
  94             s += pass_to_ugettext(', %(number)d %(type)s') % {'number': count2, 'type': name2(count2)}
  95     return s