Added option to restrict the form field and fixed how empty objects are handled.

Author: derek-schaefer

README.rst

@@ -65,6 +65,7 @@ Add a ``JSONField`` to your model like any other field.
  - ``decoder``: Custom JSON decoder (default: ``json_field.fields.JSONDecoder``)
  - ``encoder_kwargs``: Specify all arguments to the encoder (overrides ``encoder``)
  - ``decoder_kwargs``: Specify all arguments to the decoder (overrides ``decoder``)
+ - ``simple_formfield``: Restrict use of the ``datetime`` and ``Decimal`` objects in the form field
 
 License
 -------

json_field/fields.py

@@ -68,6 +68,7 @@ def __init__(self, *args, **kwargs):
             'invalid': _(u'Enter a valid JSON object')
         }
         self._db_type = kwargs.pop('db_type', None)
+        self.simple_formfield = kwargs.pop('simple_formfield', False)
 
         encoder = kwargs.pop('encoder', DjangoJSONEncoder)
         decoder = kwargs.pop('decoder', JSONDecoder)
@@ -91,7 +92,7 @@ def db_type(self, connection):
         return super(JSONField, self).db_type(connection)
 
     def to_python(self, value):
-        if not value:
+        if value is None: # allow blank objects
             return None
         if isinstance(value, basestring):
             try:
@@ -114,6 +115,7 @@ def value_from_object(self, obj):
     def formfield(self, **kwargs):
         defaults = {
             'form_class': kwargs.get('form_class', JSONFormField),
+            'simple': self.simple_formfield,
             'encoder_kwargs': self.encoder_kwargs,
             'decoder_kwargs': self.decoder_kwargs,
         }

json_field/forms.py

@@ -7,6 +7,7 @@
 class JSONFormField(fields.Field):
 
     def __init__(self, *args, **kwargs):
+        self.simple = kwargs.pop('simple', False)
         self.encoder_kwargs = kwargs.pop('encoder_kwargs')
         self.decoder_kwargs = kwargs.pop('decoder_kwargs')
         super(JSONFormField, self).__init__(*args, **kwargs)
@@ -21,15 +22,25 @@ def clean(self, value):
 
         json_globals = { # safety first!
             '__builtins__': None,
-            'datetime': datetime,
-            'Decimal': decimal.Decimal,
+        }
+        if not self.simple: # optional restriction
+            json_globals.update({
+                'datetime': datetime,
+                'Decimal': decimal.Decimal,
+            })
+        json_locals = { # value compatibility
+            'null': None,
+            'true': True,
+            'false': False,
         }
         try:
-            value = json.dumps(eval(value, json_globals, {}), **self.encoder_kwargs)
+            value = json.dumps(eval(value, json_globals, json_locals), **self.encoder_kwargs)
         except Exception, e: # eval can throw many different errors
             raise util.ValidationError('%s (Caught "%s")' % (self.help_text, e))
+
         try:
             json.loads(value, **self.decoder_kwargs)
         except ValueError, e:
             raise util.ValidationError('%s (Caught "%s")' % (self.help_text, e))
+
         return value

test_project/app/models.py

@@ -5,4 +5,4 @@
 class Test(models.Model):
 
     json = JSONField()
-    json_null = JSONField(blank=True, null=True)
+    json_null = JSONField(blank=True, null=True, simple_formfield=True)

test_project/app/tests.py

@@ -28,14 +28,14 @@ def test_null(self):
         self.assertEqual(None, t1.json)
         self.assertEqual('null', t1.get_json_json())
         t2 = Test.objects.create(json='')
-        self.assertEqual(None, t2.json)
-        self.assertEqual('null', t2.get_json_json())
+        self.assertEqual('', t2.json)
+        self.assertEqual('""', t2.get_json_json())
         t3 = Test.objects.create(json_null=None)
         self.assertEqual(None, t3.json_null)
         self.assertEqual('null', t3.get_json_null_json())
         t4 = Test.objects.create(json_null='')
-        self.assertEqual(None, t4.json_null)
-        self.assertEqual('null', t4.get_json_null_json())
+        self.assertEqual('', t4.json_null)
+        self.assertEqual('""', t4.get_json_null_json())
 
     def test_decimal(self):
         t1 = Test.objects.create(json=Decimal(1.24))
@@ -72,9 +72,9 @@ def test_get_set_json(self):
         t1 = Test.objects.create(json={'test':123})
         self.assertEqual({'test':123}, t1.json)
         self.assertEqual('{"test": 123}', t1.get_json_json())
-        t2 = Test.objects.create()
-        self.assertEqual(None, t2.json)
-        self.assertEqual('null', t2.get_json_json())
+        t2 = Test.objects.create(json='')
+        self.assertEqual('', t2.json)
+        self.assertEqual('""', t2.get_json_json())
         self.assertEqual(None, t2.json_null)
         self.assertEqual('null', t2.get_json_null_json())
         t3 = Test.objects.create(json=[1,2,3])