Django forms.FileField(required=True) is passing validation if empty

Question

I have a Django Form (not a ModelForm) with a required FileField. According to the FileField documentation, validation of the FileField should validate that non-empty file data has been bound to the form, but I am not seeing this behavior. Instead I am able to submit the form without a file and the form passes validation. The expected behavior would be to fail validation. Things work as expected when a file is specified in the form. My form looks something like this: ``` class BucketUploadForm(forms.Form): file = forms.FileField(required=True) # required=True is the default, but I'm being explicit def clean(self): upload_to = '/some/path' upload_to += self.cleaned_data['file'].name # this is raising a KeyError ``` My view looks something like this: ``` def bucket_upload(request): if request.method == 'POST': form = BucketUploadForm(request.POST, request.FILES) if form.is_valid(): # this is raising the aforementioned KeyError when no file is submitted do_stuff() return HttpResponseRedi…

Accepted Answer

I think I've seen this before. From anecdotal experience it seems like Django does not stop validation if a field is missing (e.g. it will call clean() even if missing required fields). It says a required field is missing by not including the field name in cleaned_data.

Scott pointed out it is documented here:

For any field, if the Field.clean() method raises a ValidationError, any field-specific cleaning method is not called. However, the cleaning methods for all remaining fields are still executed.

Therefore, I think the solution is just to program your clean() method defensively by checking if the 'file' key is in cleaned_data and if it isn't, just return cleaned_data as is. Django already knows the required field is missing, so is_valid() will fail and no harm will come.

```
def clean(self):
  upload_to = '/some/path'
  if not 'file' in self.cleaned_data:
    return self.cleaned_data
  upload_to += self.cleaned_data['file'].name
```

Django forms.FileField(required=True) is passing validation if empty

Solution

Problem