Allow (de)serializing CalendarRange and DateRange Parameters

param/__init__.py

@@ -2127,6 +2127,37 @@ def _validate_value(self, val, allow_None):
                              "is before start datetime %s." %
                              (self.name, val[1], val[0]))
 
+    @classmethod
+    def serialize(cls, value):
+        if value is None:
+            return 'null'
+        # List as JSON has no tuple representation
+        serialized = []
+        for v in value:
+            if not isinstance(v, (dt.datetime, dt.date)): # i.e np.datetime64
+                v = v.astype(dt.datetime)
+            # Separate date and datetime to deserialize to the right type.
+            if type(v) == dt.date:
+                v = v.strftime("%Y-%m-%d")
+            else:
+                v = v.strftime("%Y-%m-%dT%H:%M:%S.%f")
+            serialized.append(v)
+        return serialized
+
+    def deserialize(cls, value):
+        if value == 'null':
+            return None
+        deserialized = []
+        for v in value:
+            # Date
+            if len(v) == 10:
+                v = dt.datetime.strptime(v, "%Y-%m-%d").date()
+            # Datetime
+            else:
+                v = dt.datetime.strptime(v, "%Y-%m-%dT%H:%M:%S.%f")
+            deserialized.append(v)
+        # As JSON has no tuple representation
+        return tuple(deserialized)
 
 
 class CalendarDateRange(Range):
@@ -2148,6 +2179,20 @@ def _validate_value(self, val, allow_None):
                              "%s is before start date %s." %
                              (self.name, val[1], val[0]))
 
+    @classmethod
+    def serialize(cls, value):
+        if value is None:
+            return 'null'
+        # As JSON has no tuple representation
+        return [v.strftime("%Y-%m-%d") for v in value]
+
+    @classmethod
+    def deserialize(cls, value):
+        if value == 'null':
+            return None
+        # As JSON has no tuple representation
+        return tuple([dt.datetime.strptime(v, "%Y-%m-%d").date() for v in value])
+
 
 class Event(Boolean):
     """

tests/API1/testjsonserialization.py

@@ -18,20 +18,27 @@
         raise ImportError("PARAM_TEST_JSONSCHEMA=1 but jsonschema not available.")
     validate = None
 
+now = datetime.datetime.now()
+after_now = now + datetime.timedelta(days=1)
+
 try:
     import numpy as np
     ndarray = np.array([[1,2,3],[4,5,6]])
+    npdt1 = np.datetime64(now)
+    npdt2 = np.datetime64(after_now)
 except:
-    np, ndarray = None, None
+    np, ndarray, npdt1, npdt2 = None, None, None, None
 
 np_skip = skipIf(np is None, "NumPy is not available")
 
 try:
     import pandas as pd
     df1 = pd.DataFrame({'A':[1,2,3], 'B':[1.1,2.2,3.3]})
     df2 = pd.DataFrame({'A':[1.1,2.2,3.3], 'B':[1.1,2.2,3.3]})
+    pdts1 = pd.Timestamp(now)
+    pdts2 = pd.Timestamp(after_now)
 except:
-    pd, df1, df2 = None, None, None
+    pd, df1, df2, pdts1, pdts2 = None, None, None, None, None
 
 pd_skip = skipIf(pd is None, "pandas is not available")
 
@@ -52,6 +59,8 @@ class TestSet(param.Parameterized):
     e = param.List([1,2,3], class_=int)
     f = param.List([1,2,3])
     g = param.Date(default=datetime.datetime.now())
+    g2 = None if np is None else param.Date(default=npdt1)
+    g3 = None if pd is None else param.Date(default=pdts1)
     h = param.Tuple(default=(1,2,3), length=3)
     i = param.NumericTuple(default=(1,2,3,4))
     j = param.XYCoordinates(default=(32.1, 51.5))
@@ -73,6 +82,20 @@ class TestSet(param.Parameterized):
     y = None if np is None else param.Array(default=None)
     z = None if pd is None else param.DataFrame(default=None, allow_None=True)
     aa = param.Tuple(default=None, allow_None=True, length=1)
+    ab = param.CalendarDateRange(default=(
+        datetime.date(2020, 1, 1),
+        datetime.date(2021, 1, 1)
+    ))
+    ac = param.DateRange(default=(
+        datetime.date(2020, 1, 1),
+        datetime.date(2021, 1, 1)
+    ))
+    ad = param.DateRange(default=(
+        datetime.datetime(2020, 1, 1, 1, 1, 1, 1),
+        datetime.datetime(2021, 1, 1, 1, 1, 1, 1)
+    ))
+    ae = None if np is None else param.DateRange(default=(npdt1, npdt2))
+    af = None if pd is None else param.DateRange(default=(pdts1, pdts2))
 
 
 test = TestSet(a=29)
@@ -128,6 +151,23 @@ def test_serialize_date_class(self):
     def test_serialize_date_instance(self):
         self._test_serialize(test, 'g')
 
+    @np_skip
+    def test_serialize_date_numpy_class(self):
+        self._test_serialize(TestSet, 'g2')
+
+    @np_skip
+    def test_serialize_date_numpy_instance(self):
+        self._test_serialize(test, 'g2')
+        self._test_serialize(test, 'g')
+
+    @pd_skip
+    def test_serialize_date_pandas_class(self):
+        self._test_serialize(TestSet, 'g3')
+
+    @pd_skip
+    def test_serialize_date_pandas_instance(self):
+        self._test_serialize(test, 'g3')
+
     def test_serialize_tuple_class(self):
         self._test_serialize(TestSet, 'h')
 
@@ -194,6 +234,39 @@ def test_pandas_instance_serialization(self):
             else:
                 self.assertTrue(getattr(test, pname).equals(deserialized[pname]))
 
+    def test_serialize_calendar_date_range_class(self):
+        self._test_serialize(TestSet, 'ab')
+
+    def test_serialize_calendar_date_range_instance(self):
+        self._test_serialize(test, 'ab')
+
+    def test_serialize_date_range_class(self):
+        self._test_serialize(TestSet, 'ac')
+
+    def test_serialize_date_range_instance(self):
+        self._test_serialize(test, 'ac')
+
+    def test_serialize_datetime_range_class(self):
+        self._test_serialize(TestSet, 'ad')
+
+    def test_serialize_datetime_range_instance(self):
+        self._test_serialize(test, 'ad')
+
+    @np_skip
+    def test_serialize_datetime_range_numpy_class(self):
+        self._test_serialize(TestSet, 'ae')
+
+    @np_skip
+    def test_serialize_datetime_range_numpy_instance(self):
+        self._test_serialize(test, 'ae')
+
+    @pd_skip
+    def test_serialize_datetime_range_pandas_class(self):
+        self._test_serialize(TestSet, 'af')
+
+    @pd_skip
+    def test_serialize_datetime_range_pandas_instance(self):
+        self._test_serialize(test, 'af')
 
 
 class TestJSONSerialization(TestSerialization):