[Python-checkins] cpython: #665194: Add a localtime function to email.utils.
r.david.murray
python-checkins at python.org
Sat May 26 05:23:32 CEST 2012
http://hg.python.org/cpython/rev/df12ce0c96eb
changeset: 77157:df12ce0c96eb
user: R David Murray <rdmurray at bitdance.com>
date: Fri May 25 23:22:59 2012 -0400
summary:
#665194: Add a localtime function to email.utils.
Without this function people would be tempted to use the other date functions
in email.utils to compute an aware localtime, and those functions are not as
good for that purpose as this code. The code is Alexander Belopolsy's from
his proposed patch for issue 9527, with a fix (and additional tests) by Brian
K. Jones.
files:
Doc/library/email.util.rst | 18 ++++-
Lib/email/utils.py | 53 +++++++++++++
Lib/test/test_email/test_utils.py | 73 +++++++++++++++++++
Misc/ACKS | 1 +
Misc/NEWS | 3 +
5 files changed, 146 insertions(+), 2 deletions(-)
diff --git a/Doc/library/email.util.rst b/Doc/library/email.util.rst
--- a/Doc/library/email.util.rst
+++ b/Doc/library/email.util.rst
@@ -93,8 +93,6 @@
corresponding a :class:`~datetime.timezone` :class:`~datetime.tzinfo`.
.. versionadded:: 3.3
-
-
.. function:: mktime_tz(tuple)
Turn a 10-tuple as returned by :func:`parsedate_tz` into a UTC timestamp. It
@@ -140,6 +138,22 @@
.. versionadded:: 3.3
+.. function:: localtime(dt=None)
+
+ Return local time as an aware datetime object. If called without
+ arguments, return current time. Otherwise *dt* argument should be a
+ :class:`~datetime.datetime` instance, and it is converted to the local time
+ zone according to the system time zone database. If *dt* is naive (that
+ is, ``dt.tzinfo`` is ``None``), it is assumed to be in local time. In this
+ case, a positive or zero value for *isdst* causes ``localtime`` to presume
+ initially that summer time (for example, Daylight Saving Time) is or is not
+ (respectively) in effect for the specified time. A negative value for
+ *isdst* causes the ``localtime`` to attempt to divine whether summer time
+ is in effect for the specified time.
+
+ .. versionadded:: 3.3
+
+
.. function:: make_msgid(idstring=None, domain=None)
Returns a string suitable for an :rfc:`2822`\ -compliant
diff --git a/Lib/email/utils.py b/Lib/email/utils.py
--- a/Lib/email/utils.py
+++ b/Lib/email/utils.py
@@ -363,3 +363,56 @@
except LookupError:
# charset is not a known codec.
return unquote(text)
+
+
+#
+# datetime doesn't provide a localtime function yet, so provide one. Code
+# adapted from the patch in issue 9527. This may not be perfect, but it is
+# better than not having it.
+#
+
+def localtime(dt=None, isdst=-1):
+ """Return local time as an aware datetime object.
+
+ If called without arguments, return current time. Otherwise *dt*
+ argument should be a datetime instance, and it is converted to the
+ local time zone according to the system time zone database. If *dt* is
+ naive (that is, dt.tzinfo is None), it is assumed to be in local time.
+ In this case, a positive or zero value for *isdst* causes localtime to
+ presume initially that summer time (for example, Daylight Saving Time)
+ is or is not (respectively) in effect for the specified time. A
+ negative value for *isdst* causes the localtime() function to attempt
+ to divine whether summer time is in effect for the specified time.
+
+ """
+ if dt is None:
+ seconds = time.time()
+ else:
+ if dt.tzinfo is None:
+ # A naive datetime is given. Convert to a (localtime)
+ # timetuple and pass to system mktime together with
+ # the isdst hint. System mktime will return seconds
+ # sysce epoch.
+ tm = dt.timetuple()[:-1] + (isdst,)
+ seconds = time.mktime(tm)
+ else:
+ # An aware datetime is given. Use aware datetime
+ # arithmetics to find seconds since epoch.
+ delta = dt - datetime.datetime(1970, 1, 1,
+ tzinfo=datetime.timezone.utc)
+ seconds = delta.total_seconds()
+ tm = time.localtime(seconds)
+
+ # XXX: The following logic may not work correctly if UTC
+ # offset has changed since time provided in dt. This will be
+ # corrected in C implementation for platforms that support
+ # tm_gmtoff.
+ if time.daylight and tm.tm_isdst:
+ offset = time.altzone
+ tzname = time.tzname[1]
+ else:
+ offset = time.timezone
+ tzname = time.tzname[0]
+
+ tz = datetime.timezone(datetime.timedelta(seconds=-offset), tzname)
+ return datetime.datetime.fromtimestamp(seconds, tz)
diff --git a/Lib/test/test_email/test_utils.py b/Lib/test/test_email/test_utils.py
--- a/Lib/test/test_email/test_utils.py
+++ b/Lib/test/test_email/test_utils.py
@@ -1,5 +1,7 @@
import datetime
from email import utils
+import test.support
+import time
import unittest
class DateTimeTests(unittest.TestCase):
@@ -43,3 +45,74 @@
self.assertEqual(
utils.parsedate_to_datetime(self.datestring + ' -0000'),
self.naive_dt)
+
+
+class LocaltimeTests(unittest.TestCase):
+
+ def test_localtime_is_tz_aware_daylight_true(self):
+ test.support.patch(self, time, 'daylight', True)
+ t = utils.localtime()
+ self.assertIsNot(t.tzinfo, None)
+
+ def test_localtime_is_tz_aware_daylight_false(self):
+ test.support.patch(self, time, 'daylight', False)
+ t = utils.localtime()
+ self.assertIsNot(t.tzinfo, None)
+
+ def test_localtime_daylight_true_dst_false(self):
+ test.support.patch(self, time, 'daylight', True)
+ t0 = datetime.datetime(2012, 3, 12, 1, 1)
+ t1 = utils.localtime(t0, isdst=-1)
+ t2 = utils.localtime(t1)
+ self.assertEqual(t1, t2)
+
+ def test_localtime_daylight_false_dst_false(self):
+ test.support.patch(self, time, 'daylight', False)
+ t0 = datetime.datetime(2012, 3, 12, 1, 1)
+ t1 = utils.localtime(t0, isdst=-1)
+ t2 = utils.localtime(t1)
+ self.assertEqual(t1, t2)
+
+ def test_localtime_daylight_true_dst_true(self):
+ test.support.patch(self, time, 'daylight', True)
+ t0 = datetime.datetime(2012, 3, 12, 1, 1)
+ t1 = utils.localtime(t0, isdst=1)
+ t2 = utils.localtime(t1)
+ self.assertEqual(t1, t2)
+
+ def test_localtime_daylight_false_dst_true(self):
+ test.support.patch(self, time, 'daylight', False)
+ t0 = datetime.datetime(2012, 3, 12, 1, 1)
+ t1 = utils.localtime(t0, isdst=1)
+ t2 = utils.localtime(t1)
+ self.assertEqual(t1, t2)
+
+ def test_localtime_epoch_utc_daylight_true(self):
+ test.support.patch(self, time, 'daylight', True)
+ t0 = datetime.datetime(1970, 1, 1, tzinfo = datetime.timezone.utc)
+ t1 = utils.localtime(t0)
+ self.assertEqual(t0, t1)
+
+ def test_localtime_epoch_utc_daylight_false(self):
+ test.support.patch(self, time, 'daylight', False)
+ t0 = datetime.datetime(1970, 1, 1, tzinfo = datetime.timezone.utc)
+ t1 = utils.localtime(t0)
+ self.assertEqual(t0, t1)
+
+ def test_localtime_epoch_notz_daylight_true(self):
+ test.support.patch(self, time, 'daylight', True)
+ t0 = datetime.datetime(1970, 1, 1)
+ t1 = utils.localtime(t0)
+ t2 = utils.localtime(t0.replace(tzinfo=None))
+ self.assertEqual(t1, t2)
+
+ def test_localtime_epoch_notz_daylight_false(self):
+ test.support.patch(self, time, 'daylight', False)
+ t0 = datetime.datetime(1970, 1, 1)
+ t1 = utils.localtime(t0)
+ t2 = utils.localtime(t0.replace(tzinfo=None))
+ self.assertEqual(t1, t2)
+
+
+if __name__ == '__main__':
+ unittest.main()
diff --git a/Misc/ACKS b/Misc/ACKS
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -506,6 +506,7 @@
Matt Joiner
Thomas Jollans
Nicolas Joly
+Brian K. Jones
Evan Jones
Jeremy Jones
Richard Jones
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -46,6 +46,9 @@
Library
-------
+- Issue #665194: Added a localtime function to email.utils to provide an
+ aware local datetime for use in setting Date headers.
+
- Issue #12586: Added new provisional policies that implement convenient
unicode support for email headers. See What's New for details.
--
Repository URL: http://hg.python.org/cpython
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