CODEWITHSUNDEEP
djangodjango-modelsdjango-forms
davidtgq
davidtgq

Reputation: 4010

Django how to detect if a form field was filled in?

In my models.py, I override save() to manipulate the ImageField before saving it.

class Image(models.Model):
    caption = models.Charfield(max_length=254)
    image = models.ImageField(upload_to='')

    def save(self, *args, **kwargs):
        if self.image:
            # image manipulations
            super(Image, self).save(*args, **kwargs)

The manipulation should not run on the image if the object is saved without changing the ImageField, i.e. the user changes some other field like a CharField and updates the object. I didn't test this, but I presume that in the above code, self.image will always be True even if the user saves without uploading a new image to replace the old one.

So, I plan to check this based on whether or not an image file was uploaded by the user to begin with:

if form.is_valid():
    instance = form.save(commit=False)
    if form.cleaned_data.get('image'):
        image_was_uploaded = True
    instance.save(image_was_uploaded=image_was_uploaded)

Is this a valid method to accomplish this, or is there a better/more Pythonic approach (that hopefully works within models.py so Admin and DRF benefit from the same functionality)?

Upvotes: 1

Views: 586

Answers (2)

sumajumd
sumajumd

Reputation: 221

I would do it in the form class itself by overriding the clean method and checking it. when you call is_valid() from your view then it will inturn call the clean method where you can do this checking.

Upvotes: 0

Clément Mangin
Clément Mangin

Reputation: 434

You may want to look at a custom ImageField, which would handle your custom processing in its clean method. Take a look at this for instance: https://djangosnippets.org/snippets/2206/

Upvotes: 2

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