#18515 closed Bug (fixed)
Problematic validation code in FileField
Reported by: | Michael Angeletti | Owned by: | nobody |
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Component: | File uploads/storage | Version: | 1.4 |
Severity: | Normal | Keywords: | max_length, FileField, fields |
Cc: | Michael Angeletti | Triage Stage: | Accepted |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
The following code in django.db.models.fields.files
(line # 235 in master @ HEAD) is problematic.
def validate(self, value, model_instance): """ Validates that the generated file name still fits within max_length. """ # The generated file name stored in the database is generally longer # than the uploaded file name. Using the length of generated name in # the error message would be confusing. However, in the common case # (ie. upload_to='path/to/upload/dir'), the length of the generated # name equals the length of the uploaded name plus a constant. Thus # we can tell the user how much shorter the name should be (roughly). length = len(self.generate_filename(model_instance, value.name)) if self.max_length and length > self.max_length: error_values = {'extra': length - self.max_length} raise ValidationError(self.error_messages['max_length'] % error_values)
Given the following:
def oops_asset_path(instance, filename): """ Returns the upload path for a ``Oops.asset``. """ return 'oops/user_{upk}/{dt}/{fn}'.format( upk=instance.user_id, dt=timezone.now().strftime('%Y_%j_%H_%M_%S_%f'), fn=re.sub(r'[^\w\.]', '_', filename).lower()) class Oops(models.Model): asset = models.FileField(_(u'asset'), upload_to=oops_asset_path)
When an Oops
instance is saved with the asset
file name the-best-file-name-ever.jpg
, it's converted to something like:
oops/user_3145/2012_178_00_16_02_738638/the_best_file_name_ever.jpg
which is expected. Then, when the Oops
is saved again in a form (e.g., an inline model formset I use for multiple uploads) the above validation code runs the existing name through my oops_asset_path
, which returns:
oops/user_3145/2012_178_00_16_03_457362/oops_user_3145_2012_178_00_16_02_738638_the_best_file_name_ever.jpg
This causes the max_length
validation error, since the new name is clearly too long:
Filename is 7 characters too long.
The file name isn't changed permanently, but these erroneous validation errors are only avoided by increasing the field's max_length
.
I can't think of any solution to this that doesn't include either a database query or else some sort of annotation on the FileField
by forms... both of which scare me.
Attachments (2)
Change History (10)
comment:1 by , 12 years ago
Cc: | added |
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Type: | Uncategorized → Bug |
comment:2 by , 12 years ago
Type: | Bug → Uncategorized |
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comment:3 by , 12 years ago
Component: | Uncategorized → File uploads/storage |
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Has patch: | set |
Triage Stage: | Unreviewed → Accepted |
Type: | Uncategorized → Bug |
by , 12 years ago
Attachment: | 18515-1.diff added |
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comment:4 by , 12 years ago
Resolution: | → fixed |
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Status: | new → closed |
Do not always regenerate filename in FileField validation