Added MaxValueValidator to NumberFilter.

django_filters/filters.py

@@ -2,6 +2,7 @@
 from datetime import timedelta
 
 from django import forms
+from django.core.validators import MaxValueValidator
 from django.db.models import Q
 from django.db.models.constants import LOOKUP_SEP
 from django.forms.utils import pretty_name
@@ -357,6 +358,23 @@ class ModelMultipleChoiceFilter(QuerySetRequestMixin, MultipleChoiceFilter):
 class NumberFilter(Filter):
     field_class = forms.DecimalField
 
+    def get_max_validator(self):
+        """
+        Return a MaxValueValidator for the field, or None to disable.
+        """
+        return MaxValueValidator(1e50)
+
+    @property
+    def field(self):
+        if not hasattr(self, '_field'):
+            field = super().field
+            max_validator = self.get_max_validator()
+            if max_validator:
+                field.validators.append(max_validator)
+
+            self._field = field
+        return self._field
+
 
 class NumericRangeFilter(Filter):
     field_class = RangeField

docs/ref/filters.txt

@@ -426,6 +426,12 @@ QuerySet, which then gets used as the model's manager::
 Filters based on a numerical value, used with ``IntegerField``, ``FloatField``,
 and ``DecimalField`` by default.
 
+.. method:: NumberFilter.get_max_validator()
+
+    Return a ``MaxValueValidator`` instance that will be added to
+    ``field.validators``. By default uses a limit value of ``1e50``. Return
+    ``None`` to disable maximum value validation.
+
 ``NumericRangeFilter``
 ~~~~~~~~~~~~~~~~~~~~~~
 

tests/test_forms.py

@@ -255,3 +255,17 @@ def test_is_bound_and_not_valid(self):
         self.assertFalse(f.is_valid())
         self.assertEqual(f.data, {'price': 'four dollars'})
         self.assertEqual(f.errors, {'price': ['Enter a number.']})
+
+    def test_number_filter_max_value_validation(self):
+        class F(FilterSet):
+            class Meta:
+                model = Book
+                fields = ['average_rating']
+
+        f = F({'average_rating': '1E1001'})
+        self.assertTrue(f.is_bound)
+        self.assertFalse(f.is_valid())
+        self.assertEqual(
+            f.errors,
+            {'average_rating': ['Ensure this value is less than or equal to 1e+50.']}
+        )