[2383] Properly convert microseconds in date_str_to_datetime helper.

Stop this helper function from incorrectly parsing a UTC offset "+0100" as
100 microseconds.

Now, if passed UTC offset as "+0100", this function will not parse the
timestamp.  The same behaviour as when it's passed "+01:00" as a UTC
offset.

ckan/lib/helpers.py

@@ -594,12 +594,34 @@ def datetime_to_date_str(datetime_):
     return datetime_.isoformat()
 
 def date_str_to_datetime(date_str):
-    '''Takes an ISO format timestamp and returns the equivalent
-    datetime.datetime object.
+    '''Convert ISO-like formatted datestring to datetime object.
+
+    This function converts ISO format date- and datetime-strings into
+    datetime objects.  Times may be specified down to the microsecond.  UTC
+    offset or timezone information may **not** be included in the string.
+
+    Note - Although originally documented as parsing ISO date(-times), this
+           function doesn't fully adhere to the format.  This function will
+           throw a ValueError if the string contains UTC offset information.
+           So in that sense, it is less liberal than ISO format.  On the
+           other hand, it is more liberal of the accepted delimiters between
+           the values in the string.  Also, it allows microsecond precision,
+           despite that not being part of the ISO format.
     '''
-    # Doing this split is more accepting of input variations than doing
-    # a strptime. Also avoids problem with Python 2.5 not having %f.
-    return datetime.datetime(*map(int, re.split('[^\d]', date_str)))
+
+    time_tuple = re.split('[^\d]+', date_str, maxsplit=5)
+
+    # Extract seconds and microseconds
+    if len(time_tuple) >= 6:
+        m = re.match('(?P<seconds>\d{2})(\.(?P<microseconds>\d{6}))?$',
+                     time_tuple[5])
+        if not m:
+            raise ValueError
+        seconds = int(m.groupdict().get('seconds'))
+        microseconds = int(m.groupdict(0).get('microseconds'))
+        time_tuple = time_tuple[:5] + [seconds, microseconds]
+
+    return datetime.datetime(*map(int, time_tuple))
 
 def parse_rfc_2822_date(date_str, assume_utc=True):
     """

ckan/tests/lib/test_helpers.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 import time
 import datetime
-from nose.tools import assert_equal
+from nose.tools import assert_equal, assert_raises
 
 from pylons import config 
 
@@ -38,6 +38,10 @@ def test_datetime_to_date_str(self):
         res = h.datetime_to_date_str(datetime.datetime(2008, 4, 13, 20, 40, 20, 123456))
         assert_equal(res, '2008-04-13T20:40:20.123456')
 
+    def test_date_str_to_datetime_date_only(self):
+        res = h.date_str_to_datetime('2008-04-13')
+        assert_equal(res, datetime.datetime(2008, 4, 13))
+
     def test_date_str_to_datetime(self):
         res = h.date_str_to_datetime('2008-04-13T20:40:20.123456')
         assert_equal(res, datetime.datetime(2008, 4, 13, 20, 40, 20, 123456))
@@ -47,6 +51,21 @@ def test_date_str_to_datetime_without_microseconds(self):
         res = h.date_str_to_datetime('2008-04-13T20:40:20')
         assert_equal(res, datetime.datetime(2008, 4, 13, 20, 40, 20))
 
+    def test_date_str_to_datetime_with_timezone(self):
+        assert_raises(ValueError,
+                      h.date_str_to_datetime,
+                      '2008-04-13T20:40:20-01:30')
+
+    def test_date_str_to_datetime_with_garbage_on_end(self):
+        assert_raises(ValueError,
+                      h.date_str_to_datetime,
+                      '2008-04-13T20:40:20foobar')
+
+    def test_date_str_to_datetime_with_ambiguous_microseconds(self):
+        assert_raises(ValueError,
+                      h.date_str_to_datetime,
+                      '2008-04-13T20:40:20.500')
+
     def test_time_ago_in_words_from_str(self):
         two_months_ago = datetime.datetime.now() - datetime.timedelta(days=65)
         two_months_ago_str = h.datetime_to_date_str(two_months_ago)