How to implement Filter in models.ForeignKey Django?

Question

Django

models

class Product(models.Model):
    name = models.CharField('Наименование', max_length=100)
    poster = models.ImageField('Постер', upload_to='products/posters/')
    description = models.TextField('Описание')
    category = models.ForeignKey(
        Category, verbose_name='Категория', on_delete=models.SET_NULL, null=True)
    price = models.PositiveIntegerField(
        'Цена', default=0, help_text='Указывать сумму в рублях')
    hide = models.BooleanField('Скрыть', default=False)
    slug = models.SlugField(max_length=160, unique=True)

class TypeSpecification(models.Model):
    category = models.ForeignKey(
        Category, verbose_name='Категория', null=True, on_delete=models.SET_NULL)
    name = models.CharField('Наименование', max_length=255)

class ProductSpecification(models.Model):
    product = models.ForeignKey(
        Product, verbose_name='Товар', on_delete=models.CASCADE)
    type_specification = models.ForeignKey(
        TypeSpecification, verbose_name='Тип характеристик', on_delete=models.CASCADE, limit_choices_to={'category': self.product.category})
    value = models.CharField('Значение', max_length=255)

It is necessary in the 'ProductSpecification' model, in the ForeignKey 'type_specification' field, to display data (from the 'TypeSpecification' model), only if the Category in the 'TypeSpecification' matches the Category in the Product. What is the best way to implement this?

Answer 1

There is no way in the model, only filtering in the form, and then if the product value is known in advance. If the product is selected in realtime, then there is already ajax and other joys, the most famous library to help django-select2