Django validating ImageField dimensions etc

Question

I have a custom clean method below:

def clean_image(self):
    image = self.cleaned_data['image']
    if image:
        from django.core.files.images import get_image_dimensions
        w, h = get_image_dimensions(image)
        if not image.content_type in settings.VALID_IMAGE_FORMATS:
            raise forms.ValidationError(u'Only *.gif, *.jpg and *.png images are allowed.')
        if w > settings.VALID_IMAGE_WIDTH or h > settings.VALID_IMAGE_HEIGHT:
            raise forms.ValidationError(u'That image is too big. The image needs to be ' + str(settings.VALID_IMAGE_WIDTH) + 'px * ' + str(settings.VALID_IMAGE_HEIGHT) + 'px (or less).')
        return image

The problem scenario is this:

An image has been uploaded. I now want to clear it using the checkbox that appears using the ImageField widget. When submitting the form to make this clear take place the clear does not.

If I remove my custom clean method the clear does work. Therefore I guess my method is doing something wrong.

try un-indent the return so that it's inline with the if statement, i.e. it is always returning the data. — Timmy O'Mahony, Sep 30 '11 at 18:16
How about [django-vimage](https://github.com/manikos/django-vimage) 3rd-party package? I have just created it and tries to solve such scenarios. Greetings :) — nik_m, Apr 27 '18 at 17:16

score 9 · Answer 1 · answered May 07 '13 at 17:52

There are 3 problems when django realize this validations:

Django need obtain the value of these field, always need return a value
Need put class Meta with the name of the model you used.
In this sentences need put .get this way
```
self.cleaned_data.get['image']
```

The code looks like this:

class Meta: 
    model = NameModel    

def clean_image(self):
    image = self.cleaned_data.get['image']
    if image:
        from django.core.files.images import get_image_dimensions
        w, h = get_image_dimensions(image)
        if not image.content_type in settings.VALID_IMAGE_FORMATS:
            raise forms.ValidationError(u'Only *.gif, *.jpg and *.png images are allowed.')
        if w > settings.VALID_IMAGE_WIDTH or h > settings.VALID_IMAGE_HEIGHT:
            raise forms.ValidationError(u'That image is too big. The image needs to be ' +     str(settings.VALID_IMAGE_WIDTH) + 'px * ' + str(settings.VALID_IMAGE_HEIGHT) + 'px (or less).')
    return image

Point 1 is the answer here - you must ensure that `clean_image` returns a value, this allows for the Django admin clear function to occur. — jamesc, Mar 01 '14 at 17:48
I was getting "Not subscriptable" errors until I changed the above to `image = self.cleaned_data['image']` — shacker, Apr 20 '16 at 19:16

score 0 · Answer 2 · answered Sep 30 '11 at 19:16

0

I think it isn't returning image from cleaned_data. You shoudl check that, because your coding looks fine.

answered Sep 30 '11 at 19:16

Guilherme David da Costa

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Django validating ImageField dimensions etc

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