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# -*- Mode: Python; tab-width: 4 -*-
import re
import string
import time
def concat (*args):
return ''.join (args)
def join (seq, field=' '):
return field.join (seq)
def group (s):
return '(' + s + ')'
short_days = ['sun','mon','tue','wed','thu','fri','sat']
long_days = ['sunday','monday','tuesday','wednesday','thursday','friday','saturday']
short_day_reg = group (join (short_days, '|'))
long_day_reg = group (join (long_days, '|'))
daymap = {}
for i in range(7):
daymap[short_days[i]] = i
daymap[long_days[i]] = i
hms_reg = join (3 * [group('[0-9][0-9]')], ':')
months = ['jan','feb','mar','apr','may','jun','jul','aug','sep','oct','nov','dec']
monmap = {}
for i in range(12):
monmap[months[i]] = i+1
months_reg = group (join (months, '|'))
# From draft-ietf-http-v11-spec-07.txt/3.3.1
# Sun, 06 Nov 1994 08:49:37 GMT ; RFC 822, updated by RFC 1123
# Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
# Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format
# rfc822 format
rfc822_date = join (
[concat (short_day_reg,','), # day
group('[0-9][0-9]?'), # date
months_reg, # month
group('[0-9]+'), # year
hms_reg, # hour minute second
'gmt'
],
' '
)
rfc822_reg = re.compile (rfc822_date)
def unpack_rfc822 (m):
g = m.group
a = string.atoi
return (
a(g(4)), # year
monmap[g(3)], # month
a(g(2)), # day
a(g(5)), # hour
a(g(6)), # minute
a(g(7)), # second
0,
0,
0
)
# rfc850 format
rfc850_date = join (
[concat (long_day_reg,','),
join (
[group ('[0-9][0-9]?'),
months_reg,
group ('[0-9]+')
],
'-'
),
hms_reg,
'gmt'
],
' '
)
rfc850_reg = re.compile (rfc850_date)
# they actually unpack the same way
def unpack_rfc850 (m):
g = m.group
a = string.atoi
return (
a(g(4)), # year
monmap[g(3)], # month
a(g(2)), # day
a(g(5)), # hour
a(g(6)), # minute
a(g(7)), # second
0,
0,
0
)
# parsdate.parsedate - ~700/sec.
# parse_http_date - ~1333/sec.
def build_http_date (when):
return time.strftime ('%a, %d %b %Y %H:%M:%S GMT', time.gmtime(when))
def parse_http_date (d):
d = string.lower (d)
tz = time.timezone
m = rfc850_reg.match (d)
if m and m.end() == len(d):
retval = int (time.mktime (unpack_rfc850(m)) - tz)
else:
m = rfc822_reg.match (d)
if m and m.end() == len(d):
retval = int (time.mktime (unpack_rfc822(m)) - tz)
else:
return 0
# Thanks to Craig Silverstein <csilvers@google.com> for pointing
# out the DST discrepancy
if time.daylight and time.localtime(retval)[-1] == 1: # DST correction
retval = retval + (tz - time.altzone)
return retval
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