developer.intra2net.com Git - imap-fix-internaldate/blob - date_interpreter.py

   1 '''
   2 date_interpreter.py - The module contains the MailIterator class.
   3
   4 Copyright (c) 2012 Intra2net AG
   5 Author: Plamen Dimitrov
   6
   7 This program is free software: you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation, either version 3 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16 '''
  17
  18 import datetime, time
  19 import re
  20
  21 #reg expressions
  22 RECEIVED_DATE = re.compile(r'(0?[1-9]|[1-2][0-9]|3[01])\s+([A-Z][a-z][a-z])\s+'
  23         r'(19[0-9]{2}|[2-9][0-9]{3}|[0-9]{2})\s+(2[0-3]|[0-1][0-9]):([0-5][0-9])(?::(60|[0-5][0-9]))?\s*'
  24         r'(?:([-\+])([0-9]{2})([0-5][0-9]))*')
  25 INTERNAL_DATE = re.compile(r'(?P<day>[ 0123][0-9])-(?P<mon>[A-Z][a-z][a-z])-(?P<year>[0-9][0-9][0-9][0-9])'
  26         r' (?P<hour>[0-9][0-9]):(?P<min>[0-9][0-9]):(?P<sec>[0-9][0-9])'
  27         r' (?P<zonen>[-+])(?P<zoneh>[0-9][0-9])(?P<zonem>[0-9][0-9])')
  28 CONTROL_SYMBOLS = re.compile(r'[\n\r\t]')
  29
  30 class DateInterpreter:
  31     """This class extracts dates from imap server responses and compares them.
  32     This class contains only static methods."""
  33
  34     def __init__(self):
  35         return
  36
  37     @classmethod
  38     def extract_internal_date(cls, fetchresult):
  39         """Extracts the internal date from INTERNALDATE, returns datetime."""
  40         return datetime.datetime.fromtimestamp(time.mktime(fetchresult))
  41
  42     @classmethod
  43     def extract_received_date(cls, fetchresult):
  44         """Extracts the first date from RECEIVED, returns datetime."""
  45         fetchresult = CONTROL_SYMBOLS.sub('', fetchresult[0][1].decode("utf-8"))
  46         received_dates = RECEIVED_DATE.findall(fetchresult)
  47         if(len(received_dates)==0):
  48             return ""
  49         else: received_date = received_dates[0]
  50         #print("Retrieved date ", received_date, " from header ", fetchresult)
  51         month = datetime.datetime.strptime(received_date[1],'%b').month
  52
  53         if(received_date[3]!=""):
  54             hours = int(received_date[3])
  55         else: hours = 0
  56         if(received_date[4]!=""):
  57             minutes = int(received_date[4])
  58         else: minutes = 0
  59         if(received_date[5]!=""):
  60             seconds = int(received_date[5])
  61         else: seconds = 0
  62
  63         if(received_date[6]!=""):
  64             zonen = received_date[6]
  65         else: zonen = b'+'
  66         if(received_date[7]!=""):
  67             zoneh = int(received_date[7])
  68         else: zoneh = 0
  69         if(received_date[8]!=""):
  70             zonem = int(received_date[8])
  71         else: zonem = 0
  72         # subtract time zone to get unified time
  73         zone = (zoneh * 60 + zonem) * 60
  74         if(zonen == b'-'):
  75             zone = -zone
  76
  77         time_tuple = (int(received_date[2]), month, int(received_date[0]), hours, minutes, seconds, -1, -1, -1)
  78         #'mktime' assumes arg in local timezone, so add timezone/altzone
  79         utc = time.mktime(time_tuple)
  80         #adjust to DST
  81         if(time.daylight and time.localtime(utc)[-1]):
  82             zone = zone + time.altzone
  83         else:
  84             zone = zone + time.timezone
  85
  86         received_time_tuple = time.localtime(utc - zone)
  87         converted_received_date = datetime.datetime.fromtimestamp(time.mktime(received_time_tuple))
  88         return converted_received_date
  89
  90     @classmethod
  91     def compare_dates(cls, date1, date2, tolerance=1800):
  92         """Compares datetime objects for deviation given certain tolerance."""
  93         """Returns 1 if there is a significant difference."""
  94         #print(date1, "<>", date2)
  95         timedelta = abs(date1 - date2)
  96         if(timedelta.total_seconds()>tolerance):
  97             return True
  98         else:
  99             return False