Fix datetime deserialization for timezone aware fields

CHANGES.rst

@@ -4,7 +4,11 @@ Changelog
 1.0a23 (unreleased)
 -------------------
 
-- Nothing changed yet.
+Bugfixes:
+
+- Fix datetime deserialization for timezone aware fields.
+  This fixes https://github.com/plone/plone.restapi/issues/253
+  [buchi]
 
 
 1.0a22 (2017-11-04)

setup.py

@@ -43,6 +43,7 @@
           'setuptools',
           'plone.rest >= 1.0a6',  # json renderer moved to plone.restapi
           'PyJWT',
+          'pytz',
       ],
       extras_require={'test': [
           'Products.Archetypes',

src/plone/restapi/deserializer/dxfields.py

@@ -8,18 +8,22 @@
 from plone.namedfile.interfaces import INamedField
 from plone.restapi.interfaces import IFieldDeserializer
 from plone.restapi.services.content.tus import TUSUpload
+from pytz import timezone
+from pytz import utc
+from z3c.form.interfaces import IDataManager
 from zope.component import adapter
 from zope.component import getMultiAdapter
+from zope.component import queryMultiAdapter
 from zope.interface import implementer
 from zope.publisher.interfaces.browser import IBrowserRequest
 from zope.schema.interfaces import ICollection
 from zope.schema.interfaces import IDatetime
 from zope.schema.interfaces import IDict
 from zope.schema.interfaces import IField
 from zope.schema.interfaces import IFromUnicode
+from zope.schema.interfaces import ITextLine
 from zope.schema.interfaces import ITime
 from zope.schema.interfaces import ITimedelta
-from zope.schema.interfaces import ITextLine
 
 
 @implementer(IFieldDeserializer)
@@ -62,14 +66,40 @@ def __call__(self, value):
 class DatetimeFieldDeserializer(DefaultFieldDeserializer):
 
     def __call__(self, value):
+        # Datetime fields may contain timezone naive or timezone aware
+        # objects. Unfortunately the zope.schema.Datetime field does not
+        # contain any information if the field value should be timezone naive
+        # or timezone aware. While some fields (start, end) store timezone
+        # aware objects others (effective, expires) store timezone naive
+        # objects.
+        # We try to guess the correct deserialization from the current field
+        # value.
+        dm = queryMultiAdapter((self.context, self.field), IDataManager)
+        current = dm.get()
+        if current is not None:
+            tzinfo = current.tzinfo
+        else:
+            tzinfo = None
+
+        # Parse ISO 8601 string with Zope's DateTime module
         try:
-            # Parse ISO 8601 string with Zope's DateTime module
-            # and convert to a timezone naive datetime in local time
-            value = DateTime(value).toZone(DateTime().localZone()).asdatetime(
-            ).replace(tzinfo=None)
+            dt = DateTime(value).asdatetime()
         except (SyntaxError, DateTimeError) as e:
             raise ValueError(e.message)
 
+        # Convert to TZ aware in UTC
+        if dt.tzinfo is not None:
+            dt = dt.astimezone(utc)
+        else:
+            dt = utc.localize(dt)
+
+        # Convert to local TZ aware or naive UTC
+        if tzinfo is not None:
+            tz = timezone(tzinfo.zone)
+            value = tz.normalize(dt.astimezone(tz))
+        else:
+            value = utc.normalize(dt.astimezone(utc)).replace(tzinfo=None)
+
         self.field.validate(value)
         return value
 

src/plone/restapi/tests/dxtypes.py

@@ -11,6 +11,7 @@
 from plone.dexterity.content import Item
 from plone.namedfile import field as namedfile
 from plone.supermodel import model
+from pytz import timezone
 from z3c.relationfield.schema import RelationChoice
 from z3c.relationfield.schema import RelationList
 from zope import schema
@@ -47,6 +48,10 @@ class IDXTestDocumentSchema(model.Schema):
     test_choice_field = schema.Choice(values=[u'foo', u'bar'], required=False)
     test_date_field = schema.Date(required=False)
     test_datetime_field = schema.Datetime(required=False)
+    test_datetime_tz_field = schema.Datetime(
+        required=False,
+        defaultFactory=lambda: timezone("Europe/Zurich").localize(
+            datetime(2017, 10, 31, 10, 0)))
     test_decimal_field = schema.Decimal(required=False)
     test_dict_field = schema.Dict(required=False)
     test_float_field = schema.Float(required=False)

src/plone/restapi/tests/test_dxfield_deserializer.py

@@ -9,6 +9,7 @@
 from plone.dexterity.utils import iterSchemata
 from plone.restapi.interfaces import IFieldDeserializer
 from plone.restapi.testing import PLONE_RESTAPI_DX_INTEGRATION_TESTING
+from pytz import timezone
 from zope.component import getMultiAdapter
 from zope.schema.interfaces import ValidationError
 
@@ -86,6 +87,30 @@ def test_datetime_deserialization_handles_timezone(self):
                                  u'2015-12-20T10:39:54.361+01')
         self.assertEqual(datetime(2015, 12, 20, 9, 39, 54, 361000), value)
 
+    def test_datetime_with_tz_deserialization_keeps_timezone(self):
+        value = self.deserialize('test_datetime_tz_field',
+                                 u'2015-12-20T10:39:54.361+01')
+        self.assertEqual(timezone("Europe/Zurich").localize(
+            datetime(2015, 12, 20, 10, 39, 54, 361000)), value)
+
+    def test_datetime_with_tz_deserialization_converts_timezone(self):
+        value = self.deserialize('test_datetime_tz_field',
+                                 u'2015-12-20T10:39:54.361-04')
+        self.assertEqual(timezone("Europe/Zurich").localize(
+            datetime(2015, 12, 20, 15, 39, 54, 361000)), value)
+
+    def test_datetime_with_tz_deserialization_adds_timezone(self):
+        value = self.deserialize('test_datetime_tz_field',
+                                 u'2015-12-20T10:39:54.361')
+        self.assertEqual(timezone("Europe/Zurich").localize(
+            datetime(2015, 12, 20, 11, 39, 54, 361000)), value)
+
+    def test_datetime_with_tz_deserialization_handles_dst(self):
+        value = self.deserialize('test_datetime_tz_field',
+                                 u'2015-05-20T10:39:54.361+02')
+        self.assertEqual(timezone("Europe/Zurich").localize(
+            datetime(2015, 05, 20, 10, 39, 54, 361000)), value)
+
     def test_decimal_deserialization_returns_decimal(self):
         value = self.deserialize('test_decimal_field', u'1.1')
         self.assertTrue(isinstance(value, Decimal), 'Not a <Decimal>')