Error when validating file extension for multiple file upload

Using Django Mystery Errors
1

When uploading multiple files using the code in this page https://docs.djangoproject.com/en/4.2/topics/http/file-uploads/#uploading-multiple-files, everything works.

but, when i add the FileExtensionValidator to the model field it raises an error:

'list' object has no attribute 'name'

from this file: python3.11/site-packages/django/core/validators.py line: #561

models.py

class Media(models.Model):
    title = models.CharField(blank=True, null=True)
    file = models.FileField(
        upload_to="library/",
        validators=[FileExtensionValidator(["png", "gif", "jpeg", "jpg", "webp"])],
    )

views.py

class MyView(View):
     ...
     def post(self, request, *args, **kwargs):
          form = UploadForm(request.POST, request.FILES, request=request)
          if form.is_valid():
              form.save(request=request)
              return redirect(reverse("media:upload"))
          return render(
              request,
              "media/upload.html",
              {"form": form},
          )

forms.py

class UploadForm(forms.ModelForm):
    file = MultipleFileField(required=False)

    class Meta:
        model = Media
        fields = ["title", "file"]
2

Hey, take a look at these File Uploads | Django documentation | Django

3

yes I did, the problem raised after i added the file extension validator to that code.

4

I’m not sure this would work without the validator. How do you expect a list of files (as returned by a MultipleFileField) will be saved in a single FileField ?

5

No, the code crashes on this line: if form.is_valid(): when I added the FileExtensionValidator. and does not pass that line.

I will save each image alone later.

6

You are using a ModelForm but the form fields definition in not in sync with the model fields definition. On the form, file correspond to multiple files (i.e. is a list of files) but on the model file is a single file, so on form field validation, passing a list of files to a validator which is supposed to validate a single file leads to the error (the validator search for the name of file to validate on the list because it expect it to be a single File, not a list).

I don’t know how you will save each file independently and how you will make a single Media object linked to several files but:

  • either you should not use a ModelForm
  • or use another field name (e.g. files) on the form for handling the multiple files and manage those multiple files in the save method of the form
7

To add to this, you do not make a single instance of Media that refers to multiple files. You need to create multiple Media instances, each instance being a reference to a single file.