Added 'none' options to filters for optional fields

netbox/utilities/filters.py

@@ -0,0 +1,43 @@
+import django_filters
+
+from django.db.models import Q
+
+
+class NullableModelMultipleChoiceFilter(django_filters.MultipleChoiceFilter):
+
+    def __init__(self, *args, **kwargs):
+        # Convert the queryset to a list of choices prefixed with a "None" option
+        queryset = kwargs.pop('queryset')
+        self.to_field_name = kwargs.pop('to_field_name', 'pk')
+        kwargs['choices'] = [(0, 'None')] + [(getattr(o, self.to_field_name), o) for o in queryset]
+        super(NullableModelMultipleChoiceFilter, self).__init__(*args, **kwargs)
+
+    def filter(self, qs, value):
+        value = value or ()  # Make sure we have an iterable
+
+        if self.is_noop(qs, value):
+            return qs
+
+        # Even though not a noop, no point filtering if empty
+        if not value:
+            return qs
+
+        q = Q()
+        for v in set(value):
+            # Filtering on NULL
+            if v == str(0):
+                arg = {'{}__isnull'.format(self.name): True}
+            # Filtering on a related field (e.g. slug)
+            elif self.to_field_name != 'pk':
+                arg = {'{}__{}'.format(self.name, self.to_field_name): v}
+            # Filtering on primary key
+            else:
+                arg = {self.name: v}
+            if self.conjoined:
+                qs = self.get_method(qs)(**arg)
+            else:
+                q |= Q(**arg)
+        if self.distinct:
+            return self.get_method(qs)(q).distinct()
+
+        return self.get_method(qs)(q)

netbox/utilities/forms.py

@@ -43,7 +43,7 @@ def get_filter_choices(model, id_field='pk', select_related=[], count_field=None
     :param id_field: Field to use as the object identifier
     :param select_related: Any related tables to include
     :param count_field: The field to use for a child COUNT() (optional)
-    :param null_option: A (value, label) tuple to include at the beginning of the list serving as "null"
+    :param null_option: A choice to include at the beginning of the list serving as "null"
     """
     queryset = model.objects.all()
     if select_related:
@@ -54,7 +54,7 @@ def get_filter_choices(model, id_field='pk', select_related=[], count_field=None
     else:
         choices = [(getattr(obj, id_field), u'{}'.format(obj)) for obj in queryset]
     if null_option:
-        choices = [null_option] + choices
+        choices = [(0, null_option)] + choices
     return choices