如何添加验证以确保模型属性是URL并且可以访问

class Product(models.Model):
    image_url = models.URLField()

from django.core.validators import URLValidator
from django.core.exceptions import ValidationError

class Product(models.Model):
    image_url = models.URLField(validators=[URLValidator()])

from django import forms

class ProductForm(forms.ModelForm):
    class Meta:
        model = Product
        fields = ['image_url']

    def clean_image_url(self):
        image_url = self.cleaned_data.get('image_url')
        validator = URLValidator()

        try:
            validator(image_url)
        except ValidationError:
            raise forms.ValidationError("Invalid URL")

        return image_url