基于Django类的通用视图“ CreateView”表单错误处理

Question

I am new to CBV and am trying to use the generic view CreateView and understand it.

In models.py I have this model:

class CartConfig(models.Model):

    cart_key = models.CharField(
       'Chave do Carrinho', max_length=40, db_index=True
    )
    PAYMENT_OPTION_CHOICES = (
        ('cash', 'Dinheiro'),
        ...
    )
    payment_option = models.CharField(
        'Opção de Pagamento', choices=PAYMENT_OPTION_CHOICES, max_length=20,
        default='cash'
    )
    address = models.ForeignKey(Address, verbose_name='Endereço de entrega', 
        blank="false"
    )

    class Meta:
        verbose_name = 'Configuração do carrinho'
        verbose_name_plural = 'Configurações do carrinho'

    def __str__(self):
        return 'Cart configs for {}'.format(self.cart_key)

That model uses a ForeignKey to Address , which is also a ManyToMany field in the User model. So, in my views.py I edited the queryset of ´adress´ field to handle only the address relationed to the current User :

class CartConfigView(CreateView):
    model = CartConfig
    template_name = 'checkout/cart_config.html'
    fields = ['address','payment_option']
    success_url = reverse_lazy('index')
    def get_context_data(self, **kwargs):
        context = super(CartConfigView, self).get_context_data(**kwargs)
        context['form'].fields['address'].queryset = get_object_or_404(User, pk=self.request.user.pk).address.all()
        context['form'].fields['address'].empty_label = None
        return context

In my template it works fine, show the right address list and creat it as well through the post form. But if the user don't select an address, it triggers the expected error NOT NULL constraint failed: checkout_cartconfig.address_id . The question is, should not the CreateView handles this error? What am I doing wrong? How can I do to the page refresh with the field.errors to show to the user the "required field" message?

Answer 1

Your model is not set up quite correctly with blank="false" . It needs to be a boolean.

address = models.ForeignKey(
    Address,
    verbose_name='Endereço de entrega',
    blank=False
)

Fun fact about Python: When resolving to a boolean, strings evaluate to true.

>>> bool("false")
True