Handle time zones with seconds in the UTC offset.

The offset is rounded to the nearest minute.

ChangeLog

@@ -1,3 +1,8 @@
+2010-05-20  Daniele Varrazzo  <daniele.varrazzo@gmail.com>
+
+	* psycopg/typecast_datetime.c: Round seconds in historical timezones to
+	the nearest minute.
+
 2010-05-17  Federico Di Gregorio  <fog@initd.org>
 
 	* Release 2.2.1.

doc/src/usage.rst

@@ -365,6 +365,38 @@ the connection or globally: see the function
     and then forget about this story.
 
 
+.. index::
+    single: Time Zones
+
+.. _tz-handling:
+
+Time zones handling
+^^^^^^^^^^^^^^^^^^^
+
+The PostgreSQL type :sql:`timestamp with time zone` is converted into Python
+`!datetime` objects with a `!tzinfo` attribute set to a
+`~psycopg2.tz.FixedOffsetTimezone` instance.
+
+    >>> cur.execute("SET TIME ZONE 'Europe/Rome';")  # UTC + 1 hour
+    >>> cur.execute("SELECT '2010-01-01 10:30:45'::timestamptz;")
+    >>> cur.fetchone()[0].tzinfo
+    psycopg2.tz.FixedOffsetTimezone(offset=60, name=None)
+
+Notice that only time zones with an integer number of minutes are supported:
+this is a limitation of the Python `!datetime` module.  A few historical time
+zones had seconds in the UTC offset: these time zones will have the offset
+rounded to the nearest minute, with an error of up to 30 seconds.
+
+    >>> cur.execute("SET TIME ZONE 'Asia/Calcutta';")  # offset was +5:53:20
+    >>> cur.execute("SELECT '1930-01-01 10:30:45'::timestamptz;")
+    >>> cur.fetchone()[0].tzinfo
+    psycopg2.tz.FixedOffsetTimezone(offset=353, name=None)
+
+.. versionchanged:: 2.2.2
+    timezones with seconds are supported (with rounding). Previously such
+    timezones raised an error.  In order to deal with them in previous
+    versions use `psycopg2.extras.register_tstz_w_secs`.
+
 
 .. index:: Transaction, Begin, Commit, Rollback, Autocommit
 

psycopg/typecast_datetime.c

@@ -134,15 +134,11 @@ typecast_PYDATETIME_cast(const char *str, Py_ssize_t len, PyObject *curs)
             Dprintf("typecast_PYDATETIME_cast: UTC offset = %ds", tz);
 
             /* The datetime module requires that time zone offsets be
-               a whole number of minutes, so fail if we have a time
+               a whole number of minutes, so truncate the seconds to the
-               zone with a seconds offset.
+               closest minute. */
-             */
+            // printf("%d %d %d\n", tz, tzmin, round(tz / 60.0));
-            if (tz % 60 != 0) {
+            tzinfo = PyObject_CallFunction(tzinfo_factory, "i",
-                PyErr_Format(PyExc_ValueError, "time zone offset %d is not "
+                (int)round(tz / 60.0));
-                             "a whole number of minutes", tz);
-                return NULL;
-            }
-            tzinfo = PyObject_CallFunction(tzinfo_factory, "i", tz / 60);
         } else {
             Py_INCREF(Py_None);
             tzinfo = Py_None;
@@ -192,15 +188,10 @@ typecast_PYTIME_cast(const char *str, Py_ssize_t len, PyObject *curs)
         Dprintf("typecast_PYTIME_cast: UTC offset = %ds", tz);
 
         /* The datetime module requires that time zone offsets be
-           a whole number of minutes, so fail if we have a time
+           a whole number of minutes, so truncate the seconds to the
-           zone with a seconds offset.
+           closest minute. */
-        */
+        tzinfo = PyObject_CallFunction(tzinfo_factory, "i",
-        if (tz % 60 != 0) {
+            (int)round(tz / 60.0));
-            PyErr_Format(PyExc_ValueError, "time zone offset %d is not "
-                         "a whole number of minutes", tz);
-            return NULL;
-        }
-        tzinfo = PyObject_CallFunction(tzinfo_factory, "i", tz / 60);
     } else {
         Py_INCREF(Py_None);
         tzinfo = Py_None;

tests/test_dates.py

@@ -124,24 +124,16 @@ class DatetimeTests(unittest.TestCase, CommonDatetimeTestsMixin):
         self.check_time_tz("+01:15", 4500)
         self.check_time_tz("-01:15", -4500)
         # The Python datetime module does not support time zone
-        # offsets that are not a whole number of minutes, so we get an
+        # offsets that are not a whole number of minutes.
-        # error here.  Check that we are generating an understandable
+        # We round the offset to the nearest minute.
-        # error message.
+        self.check_time_tz("+01:15:00",  60 * (60 + 15))
-        try:
+        self.check_time_tz("+01:15:29",  60 * (60 + 15))
-            self.check_time_tz("+01:15:42", 4542)
+        self.check_time_tz("+01:15:30",  60 * (60 + 16))
-        except ValueError, exc:
+        self.check_time_tz("+01:15:59",  60 * (60 + 16))
-            self.assertEqual(str(exc), "time zone offset 4542 is not a "
+        self.check_time_tz("-01:15:00", -60 * (60 + 15))
-                             "whole number of minutes")
+        self.check_time_tz("-01:15:29", -60 * (60 + 15))
-        else:
+        self.check_time_tz("-01:15:30", -60 * (60 + 16))
-            self.fail("Expected ValueError")
+        self.check_time_tz("-01:15:59", -60 * (60 + 16))
-
-        try:
-            self.check_time_tz("-01:15:42", -4542)
-        except ValueError, exc:
-            self.assertEqual(str(exc), "time zone offset -4542 is not a "
-                             "whole number of minutes")
-        else:
-            self.fail("Expected ValueError")
 
     def check_datetime_tz(self, str_offset, offset):
         from datetime import datetime, timedelta
@@ -168,24 +160,16 @@ class DatetimeTests(unittest.TestCase, CommonDatetimeTestsMixin):
         self.check_datetime_tz("+01:15", 4500)
         self.check_datetime_tz("-01:15", -4500)
         # The Python datetime module does not support time zone
-        # offsets that are not a whole number of minutes, so we get an
+        # offsets that are not a whole number of minutes.
-        # error here.  Check that we are generating an understandable
+        # We round the offset to the nearest minute.
-        # error message.
+        self.check_datetime_tz("+01:15:00",  60 * (60 + 15))
-        try:
+        self.check_datetime_tz("+01:15:29",  60 * (60 + 15))
-            self.check_datetime_tz("+01:15:42", 4542)
+        self.check_datetime_tz("+01:15:30",  60 * (60 + 16))
-        except ValueError, exc:
+        self.check_datetime_tz("+01:15:59",  60 * (60 + 16))
-            self.assertEqual(str(exc), "time zone offset 4542 is not a "
+        self.check_datetime_tz("-01:15:00", -60 * (60 + 15))
-                             "whole number of minutes")
+        self.check_datetime_tz("-01:15:29", -60 * (60 + 15))
-        else:
+        self.check_datetime_tz("-01:15:30", -60 * (60 + 16))
-            self.fail("Expected ValueError")
+        self.check_datetime_tz("-01:15:59", -60 * (60 + 16))
-
-        try:
-            self.check_datetime_tz("-01:15:42", -4542)
-        except ValueError, exc:
-            self.assertEqual(str(exc), "time zone offset -4542 is not a "
-                             "whole number of minutes")
-        else:
-            self.fail("Expected ValueError")
 
     def test_parse_time_no_timezone(self):
         self.assertEqual(self.TIME("13:30:29", self.curs).tzinfo, None)