create DateGuesser extracted from cragr

it also moves utc2local and local2utc functions into date.py

weboob/tools/date.py

@@ -0,0 +1,114 @@
+# -*- coding: utf-8 -*-
+
+# Copyright(C) 2010-2013 Romain Bignon
+#
+# This file is part of weboob.
+#
+# weboob is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# weboob is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with weboob. If not, see <http://www.gnu.org/licenses/>.
+
+
+from datetime import date, timedelta
+try:
+    from dateutil import tz
+except ImportError:
+    raise ImportError('Please install python-dateutil')
+
+
+__all__ = ['local2utc', 'utc2local', 'LinearDateGuesser']
+
+
+def local2utc(date):
+    date = date.replace(tzinfo=tz.tzlocal())
+    date = date.astimezone(tz.tzutc())
+    return date
+
+
+def utc2local(date):
+    date = date.replace(tzinfo=tz.tzutc())
+    date = date.astimezone(tz.tzlocal())
+    return date
+
+class LinearDateGuesser(object):
+    """
+    The aim of this class is to guess the exact date object from
+    a day and a month, but not a year.
+
+    It works with a start date (default is today), and all dates must be
+    sorted from recent to older.
+    """
+
+    def __init__(self, current_date=None, date_max_bump=timedelta(7)):
+        self.date_max_bump = date_max_bump
+        if current_date is None:
+            current_date = date.today()
+        self.current_date = current_date
+
+    def try_assigning_year(self, day, month, start_year, max_year):
+        """
+        Tries to create a date object with day, month and start_year and returns
+        it.
+        If it fails due to the year not matching the day+month combination
+        (i.e. due to a ValueError -- TypeError and OverflowError are not
+        handled), the previous or next years are tried until max_year is
+        reached.
+        In case initialization still fails with max_year, this function raises
+        a ValueError.
+        """
+        while 1:
+            try:
+                return date(start_year, month, day)
+            except ValueError, e:
+                if start_year == max_year:
+                    raise e
+                start_year += cmp(max_year, start_year)
+
+    def set_current_date(self, current_date):
+        self.current_date = current_date
+
+    def guess_date(self, day, month, change_current_date=True):
+        """ Returns a date object built from a given day/month pair. """
+
+        today = self.current_date
+        # The website only provides dates using the 'DD/MM' string, so we have to
+        # determine the most possible year by ourselves. This implies tracking
+        # the current date.
+        # However, we may also encounter "bumps" in the dates, e.g. "12/11,
+        # 10/11, 10/11, 12/11, 09/11", so we have to be, well, quite tolerant,
+        # by accepting dates in the near future (say, 7 days) of the current
+        # date. (Please, kill me...)
+        # We first try to keep the current year
+        naively_parsed_date = self.try_assigning_year(day, month, today.year, today.year - 5)
+        if (naively_parsed_date.year != today.year):
+            # we most likely hit a 29/02 leading to a change of year
+            if change_current_date:
+                self.set_current_date(naively_parsed_date)
+            return naively_parsed_date
+
+        if (naively_parsed_date > today + self.date_max_bump):
+            # if the date ends up too far in the future, consider it actually
+            # belongs to the previous year
+            parsed_date = date(today.year - 1, month, day)
+            if change_current_date:
+                self.set_current_date(parsed_date)
+        elif (naively_parsed_date > today and naively_parsed_date <= today + self.date_max_bump):
+            # if the date is in the near future, consider it is a bump
+            parsed_date = naively_parsed_date
+            # do not keep it as current date though
+        else:
+            # if the date is in the past, as expected, simply keep it
+            parsed_date = naively_parsed_date
+            # and make it the new current date
+            if change_current_date:
+                self.set_current_date(parsed_date)
+        return parsed_date

weboob/tools/misc.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright(C) 2010-2011 Romain Bignon
+# Copyright(C) 2010-2013 Romain Bignon
 #
 # This file is part of weboob.
 #
@@ -20,11 +20,6 @@
 
 from __future__ import with_statement
 
-try:
-    from dateutil import tz
-except ImportError:
-    raise ImportError('Please install python-dateutil')
-
 from logging import warning
 from time import time, sleep
 from tempfile import gettempdir
@@ -32,6 +27,8 @@ import os
 import sys
 import traceback
 import types
+# keep compatibility
+from .date import local2utc, utc2local
 
 
 __all__ = ['get_backtrace', 'get_bytes_size', 'html2text', 'iter_fields',
@@ -88,12 +85,6 @@ def iter_fields(obj):
             yield attribute_name, attribute
 
 
-def local2utc(date):
-    date = date.replace(tzinfo=tz.tzlocal())
-    date = date.astimezone(tz.tzutc())
-    return date
-
-
 def to_unicode(text):
     r"""
     >>> to_unicode('ascii')
@@ -119,12 +110,6 @@ def to_unicode(text):
             return unicode(text, 'windows-1252', 'replace')
 
 
-def utc2local(date):
-    date = date.replace(tzinfo=tz.tzutc())
-    date = date.astimezone(tz.tzlocal())
-    return date
-
-
 def limit(iterator, lim):
     count = 0
     iterator = iter(iterator)