Updated JSON serialization of Date and CalendarDate to support None

param/__init__.py

@@ -1017,10 +1017,15 @@ def _validate(self, val):
 
     @classmethod
     def serialize(cls, value):
-        return list(value) # As JSON has no tuple representation
+        if value is None:
+            return 'null'
+        else:
+            return list(value) # As JSON has no tuple representation
 
     @classmethod
     def deserialize(cls, value):
+        if value == 'null':
+            return None
         return tuple(value) # As JSON has no tuple representation
 
 
@@ -1474,10 +1479,15 @@ def __init__(self, default=None, **params):
 
     @classmethod
     def serialize(cls, value):
-        return value.tolist()
+        if value is None:
+            return 'null'
+        else:
+            return value.tolist()
 
     @classmethod
     def deserialize(cls, value):
+        if value == 'null':
+            return None
         from numpy import asarray
         return asarray(value)
 
@@ -1557,10 +1567,15 @@ def _validate(self, val):
 
     @classmethod
     def serialize(cls, value):
-        return value.to_dict('records')
+        if value is None:
+            return 'null'
+        else:
+            return value.to_dict('records')
 
     @classmethod
     def deserialize(cls, value):
+        if value == 'null':
+            return None
         from pandas import DataFrame as pdDFrame
         return pdDFrame(value)
 
@@ -1925,13 +1940,18 @@ def _validate_step(self, val, step):
 
     @classmethod
     def serialize(cls, value):
+        if value is None:
+            return 'null'
         if not isinstance(value, (dt.datetime, dt.date)): # i.e np.datetime64
             value = value.astype(dt.datetime)
         return value.strftime("%Y-%m-%dT%H:%M:%S.%f")
 
     @classmethod
     def deserialize(cls, value):
-        return dt.datetime.strptime(value, "%Y-%m-%dT%H:%M:%S.%f")
+        if value == 'null':
+            return None
+        else:
+            return dt.datetime.strptime(value, "%Y-%m-%dT%H:%M:%S.%f")
 
 
 class CalendarDate(Number):
@@ -1959,11 +1979,17 @@ def _validate_step(self, val, step):
 
     @classmethod
     def serialize(cls, value):
-        return value.strftime("%Y-%m-%d")
+        if value is None:
+            return 'null'
+        else:
+            return value.strftime("%Y-%m-%d")
 
     @classmethod
     def deserialize(cls, value):
-        return dt.datetime.strptime(value, "%Y-%m-%d").date()
+        if value == 'null':
+            return None
+        else:
+            return dt.datetime.strptime(value, "%Y-%m-%d").date()
 
 
 class Color(Parameter):

tests/API1/testjsonserialization.py

@@ -41,8 +41,8 @@ class TestSet(param.Parameterized):
 
     __test__ = False
 
-    numpy_params = ['r']
-    pandas_params = ['s','t','u']
+    numpy_params = ['r','y']
+    pandas_params = ['s','t','u','z']
     conditionally_unsafe = ['f', 'o']
 
     a = param.Integer(default=5, doc='Example doc', bounds=(2,30), inclusive_bounds=(True, False))
@@ -68,6 +68,11 @@ class TestSet(param.Parameterized):
         {'A':[1,2,3], 'B':[1.1,2.2,3.3]}), columns=(1,4), rows=(2,5))
     u = None if pd is None else param.DataFrame(default=df2, columns=['A', 'B'])
     v = param.Dict({'1':2})
+    w = param.Date(default=None, allow_None=True)
+    x = param.CalendarDate(default=None, allow_None=True)
+    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)
 
 
 test = TestSet(a=29)
@@ -184,7 +189,10 @@ def test_pandas_instance_serialization(self):
         serialized = test.param.serialize_parameters(subset=test.pandas_params, mode=self.mode)
         deserialized = TestSet.param.deserialize_parameters(serialized, mode=self.mode)
         for pname in test.pandas_params:
-            self.assertTrue(getattr(test, pname).equals(deserialized[pname]))
+            if getattr(test, pname) is None:
+                self.assertTrue(deserialized[pname] is None)
+            else:
+                self.assertTrue(getattr(test, pname).equals(deserialized[pname]))