timestamp.py

#coding: utf8

import re
import time
import datetime
import dateutil.tz

# Remember offset is in seconds west of UTC, but the timezone is in
# minutes east of UTC.

def timestamp2rfc2822(timestamp, altzone=0):
    offset = -altzone
    hours, minutes = divmod(abs(offset), 3600)
    sign = '+' if offset > 0 else '-'
    zone = '%s%02d%02d' % (sign, hours, minutes // 60)
    now = time.gmtime(timestamp+offset)
    return '%s, %02d %s %04d %02d:%02d:%02d %s' % (
        ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'][now[6]],
        now[2],
        ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
         'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'][now[1] - 1],
        now[0], now[3], now[4], now[5],
        zone)

def timestamp2iso8601(timestamp, altzone=0):
    offset = -altzone
    hours, minutes = divmod(abs(offset), 3600)
    sign = '+' if offset > 0 else '-'
    zone = '%s%02d%02d' % (sign, hours, minutes // 60)
    tz = dateutil.tz.tzoffset(zone, offset)
    dt = datetime.datetime.utcfromtimestamp(timestamp)
    dt = dt.replace(tzinfo=tz)
    iso = dt.isoformat(' ')
    # '2014-05-29 09:50:55+08:00' -> '2014-05-29 09:50:55 +08:00'
    return iso[:-6] + ' ' + iso[-6:]

def timestamp2relative(timestamp, altzone=0):
    dt = datetime.datetime.utcfromtimestamp(timestamp)
    now = datetime.datetime.utcnow()
    delta = now - dt
    day = delta.days
    second = delta.seconds
    # Return quotient and remaining
    qr = lambda a, b: (a / b, a % b)
    year, day = qr(day, 365)
    month, day = qr(day, 30)
    hour, second = qr(second, 3600)
    minute, second = qr(second, 60)
    for period in ['year', 'month', 'day', 'hour', 'minute', 'second']:
        n = eval(period)
        if n > 0:
            return ('%s %ss ago' if n > 1 else '%s %s ago') % (n, period)
    return 'just now'