Ticket #9893: filefield_length_validation.diff

django/db/models/fields/files.py

@@ -13 +13 @@
 from django.db.models import signals
 from django.utils.encoding import force_unicode, smart_str
 from django.utils.translation import ugettext_lazy, ugettext as _
+from django.core.exceptions import ValidationError
 from django import forms
 from django.db.models.loading import cache
 
@@ -210 +211 @@
         instance.__dict__[self.field.name] = value
 
 class FileField(Field):
+
+    default_error_messages = {
+        'max_length': ugettext_lazy(u'Ensure this filename and path has at most %(max)d characters (it has %(length)d).')
+        }
+
     # The class to wrap instance attributes in. Accessing the file object off
     # the instance will always return an instance of attr_class.
     attr_class = FieldFile
@@ -232 +238 @@
         kwargs['max_length'] = kwargs.get('max_length', 100)
         super(FileField, self).__init__(verbose_name, name, **kwargs)
 
+    def validate(self, value, model_instance):
+        """
+        Validates that the file name plus the path still fits within max_length
+        of the field.  It throws a ValidationError if it doesn't.
+        """
+        
+        length = len(self.generate_filename(model_instance, value.name))
+        if self.max_length and length > self.max_length:
+            error_values = {'max': self.max_length, 'length': length }
+            raise ValidationError(self.error_messages['max_length'] % error_values)
+
     def get_internal_type(self):
         return "FileField"