#!/usr/bin/python2

# copy and paste this script 
# and save as date_check.py

import sys
import rfc822
from time import gmtime, mktime, timezone

# get current UTC time in seconds since epoch
current_time = mktime(gmtime())

# get email date header, if it exists
headers = rfc822.Message(sys.stdin)
header_date = headers.getdate_tz('Date')

# if no date header, delete with "no date header" error
if not header_date:
    print "The email had no Date field in the header"
    sys.exit(99)

# convert date from message header to secs since epoch
# header_date[9] is offset in secs for timezone
header_time = mktime(header_date[0:9]) - header_date[9]

time_diff = current_time - header_time

# if date is older than one year 
# delete the message with an error
year_seconds = 365*24*60*60
if time_diff > year_seconds:
    print "The header date in the email was more than a year old."
    sys.exit(99)

# if date is more than two days in the future
# delete the message with an error
two_days_future_seconds = -2*24*60*60
if time_diff < two_days_future_seconds:
    print "The header date in the email was more than two days in the future."
    sys.exit(99)