fix: add local timezone awareness for datetime fields

this likely still needs improvement, but a good starting point

src/wuttaweb/forms/schema.py

@@ -31,6 +31,7 @@ import colander
 import sqlalchemy as sa
 
 from wuttjamaican.conf import parse_list
+from wuttjamaican.util import localtime, make_utc
 
 from wuttaweb.db import Session
 from wuttaweb.forms import widgets
@@ -48,6 +49,18 @@ class WuttaDateTime(colander.DateTime):
     the Buefy datepicker + timepicker widgets.
     """
 
+    def serialize(self, node, appstruct):
+        if not appstruct:
+            return colander.null
+
+        if appstruct.tzinfo is None:
+            appstruct = localtime(appstruct)
+
+        if self.format:
+            return appstruct.strftime(self.format)
+
+        return appstruct.isoformat()
+
     def deserialize(  # pylint: disable=inconsistent-return-statements,empty-docstring
         self, node, cstruct
     ):
@@ -62,7 +75,9 @@ class WuttaDateTime(colander.DateTime):
 
         for fmt in formats:
             try:
-                return datetime.datetime.strptime(cstruct, fmt)
+                dt = datetime.datetime.strptime(cstruct, fmt)
+                dt = dt.astimezone()
+                return make_utc(dt)
             except Exception:  # pylint: disable=broad-exception-caught
                 pass
 

tests/forms/test_schema.py

@@ -19,6 +19,52 @@ from wuttaweb.testing import WebTestCase
 
 class TestWuttaDateTime(TestCase):
 
+    def test_serialize(self):
+        typ = mod.WuttaDateTime()
+        node = colander.SchemaNode(typ)
+
+        result = typ.serialize(node, colander.null)
+        self.assertIs(result, colander.null)
+
+        result = typ.serialize(node, None)
+        self.assertIs(result, colander.null)
+
+        result = typ.serialize(node, "")
+        self.assertIs(result, colander.null)
+
+        # naive, UTC
+        # TODO: must override local timezone for a complete test
+        result = typ.serialize(node, datetime.datetime(2024, 12, 11, 22, 33))
+        self.assertTrue(result.startswith("2024-12-"))
+
+        # aware, UTC
+        result = typ.serialize(
+            node, datetime.datetime(2024, 12, 11, 22, 33, tzinfo=datetime.timezone.utc)
+        )
+        self.assertEqual(result, "2024-12-11T22:33:00+00:00")
+
+        # aware, local
+        result = typ.serialize(
+            node,
+            datetime.datetime(
+                2024,
+                12,
+                11,
+                22,
+                33,
+                tzinfo=datetime.timezone(-datetime.timedelta(hours=5)),
+            ),
+        )
+        self.assertEqual(result, "2024-12-11T22:33:00-05:00")
+
+        # custom format
+        typ = mod.WuttaDateTime(format="%Y-%m-%d %I:%M %p")
+        node = colander.SchemaNode(typ)
+        result = typ.serialize(
+            node, datetime.datetime(2024, 12, 11, 22, 33, tzinfo=datetime.timezone.utc)
+        )
+        self.assertEqual(result, "2024-12-11 10:33 PM")
+
     def test_deserialize(self):
         typ = mod.WuttaDateTime()
         node = colander.SchemaNode(typ)
@@ -26,14 +72,24 @@ class TestWuttaDateTime(TestCase):
         result = typ.deserialize(node, colander.null)
         self.assertIs(result, colander.null)
 
+        result = typ.deserialize(node, None)
+        self.assertIs(result, colander.null)
+
+        result = typ.deserialize(node, "")
+        self.assertIs(result, colander.null)
+
+        # TODO: must override local timezone for a complete test
         result = typ.deserialize(node, "2024-12-11T10:33 PM")
         self.assertIsInstance(result, datetime.datetime)
-        self.assertEqual(result, datetime.datetime(2024, 12, 11, 22, 33))
+        dt = datetime.datetime(2024, 12, 11, 22, 33)
+        self.assertLess(abs((result - dt).total_seconds()), 60 * 60 * 24)
         self.assertIsNone(result.tzinfo)
 
+        # TODO: must override local timezone for a complete test
         result = typ.deserialize(node, "2024-12-11T22:33:00")
         self.assertIsInstance(result, datetime.datetime)
-        self.assertEqual(result, datetime.datetime(2024, 12, 11, 22, 33))
+        dt = datetime.datetime(2024, 12, 11, 22, 33)
+        self.assertLess(abs((result - dt).total_seconds()), 60 * 60 * 24)
         self.assertIsNone(result.tzinfo)
 
         self.assertRaises(colander.Invalid, typ.deserialize, node, "bogus")