Use faster and more robust fromisoformat when possible.

docs/peewee/api.rst

@@ -3192,8 +3192,16 @@ Fields
 
       '%Y-%m-%d %H:%M:%S.%f' # year-month-day hour-minute-second.microsecond
       '%Y-%m-%d %H:%M:%S' # year-month-day hour-minute-second
+      '%Y-%m-%d %H:%M:%S.%f%z' # ...with timezone offset
+      '%Y-%m-%d %H:%M:%S%z' # ...with timezone offset
       '%Y-%m-%d' # year-month-day
 
+   In addition, any string accepted by
+   :py:meth:`datetime.datetime.fromisoformat` is parsed automatically,
+   including the ``T`` separator and a trailing ``Z`` (UTC). Custom
+   ``formats`` are still consulted as a fallback for non-ISO inputs (e.g.
+   ``'01/02/2003 01:37 PM'``).
+
    SQLite does not have a native datetime data-type, so datetimes are
    stored as strings. This is handled transparently by Peewee, but if you
    have pre-existing data you should ensure it is stored as
@@ -3270,6 +3278,9 @@ Fields
       '%Y-%m-%d %H:%M:%S' # year-month-day hour-minute-second
       '%Y-%m-%d %H:%M:%S.%f' # year-month-day hour-minute-second.microsecond
 
+   In addition, any string accepted by
+   :py:meth:`datetime.datetime.fromisoformat` is parsed automatically.
+
    .. note::
       If the incoming value does not match a format, it is returned as-is.
 

peewee.py

@@ -5472,8 +5472,23 @@ def _date_part(date_part):
         return self.model._meta.database.extract_date(date_part, self)
     return dec
 
+# fromisoformat() is C-implemented and ~10x faster than strptime. Available
+# since 3.7; pre-3.11 is strict about the separator and rejects 'Z'.
+_fromisoformat = getattr(datetime.datetime, 'fromisoformat', None)
+
+
 def format_date_time(value, formats, post_process=None):
     post_process = post_process or (lambda x: x)
+    if _fromisoformat is not None and value:
+        s = value
+        if len(s) > 10 and s[10] == ' ':
+            s = s[:10] + 'T' + s[11:]
+        if s[-1:] == 'Z':
+            s = s[:-1] + '+00:00'
+        try:
+            return post_process(_fromisoformat(s))
+        except (TypeError, ValueError):
+            pass
     for fmt in formats:
         try:
             return post_process(datetime.datetime.strptime(value, fmt))

tests/fields.py

@@ -28,6 +28,7 @@ from decimal import ROUND_UP
 
 from peewee import NodeList
 from peewee import VirtualField
+from peewee import format_date_time
 from peewee import *
 
 from playhouse.hybrid import *
@@ -404,6 +405,38 @@ class TestDateFields(ModelTestCase):
             datetime.datetime(2002, 3, 1, 0, 0, 0),
             datetime.datetime(2002, 3, 4, 0, 0, 0)])
 
+    def test_date_time_iso_fast_path(self):
+        dm = DateModel.create(date_time='2019-01-02 03:04:05.123456')
+        dm_db = DateModel[dm.id]
+        self.assertEqual(dm_db.date_time,
+                         datetime.datetime(2019, 1, 2, 3, 4, 5, 123456))
+
+        dm = DateModel.create(date_time='2019-01-02T03:04:05')
+        dm_db = DateModel[dm.id]
+        self.assertEqual(dm_db.date_time,
+                         datetime.datetime(2019, 1, 2, 3, 4, 5))
+
+        val = format_date_time('2019-01-02T03:04:05Z',
+                               DateTimeField.formats)
+        self.assertEqual(val,
+                         datetime.datetime(2019, 1, 2, 3, 4, 5,
+                                           tzinfo=datetime.timezone.utc))
+
+        val = format_date_time('2019-01-02', DateField.formats,
+                               lambda x: x.date())
+        self.assertEqual(val, datetime.date(2019, 1, 2))
+
+    def test_date_time_format_fallback(self):
+        val = format_date_time('01/02/2003 01:37 PM',
+                               ['%m/%d/%Y %I:%M %p'])
+        self.assertEqual(val, datetime.datetime(2003, 1, 2, 13, 37))
+
+        val = format_date_time('11:12:13', TimeField.formats,
+                               lambda x: x.time())
+        self.assertEqual(val, datetime.time(11, 12, 13))
+
+        self.assertEqual(format_date_time('not a date', []), 'not a date')
+
     def test_to_timestamp(self):
         dt = datetime.datetime(2019, 1, 2, 3, 4, 5)
         ts = calendar.timegm(dt.utctimetuple())