Django populate select field based on model query

Question

I have the following model

class DNS(models.Model):
    domain = models.ForeignKey(Domain)
    host_start = models.CharField(max_length=150, blank=True, null=True)
    type = models.SmallIntegerField(max_length=1, default=0, choices=DNS_CHOICE)
    value = models.SmallIntegerField(max_length=3, default=0, blank=True, null=True)
    ip = models.IPAddressField(blank=True, null=True)
    host_end = models.ForeignKey("DNS", blank=True, null=True)
    other_end = HostnameField(max_length=150, blank=True, null=True)
    created = models.DateTimeField(auto_now_add=True)
    sticky = models.BooleanField(default=0)
    other = models.BooleanField(default=0)

When I try to init a form with just foreignkeys on host_end.. it always shows all entries in the DNS table

domain = Domain.objects.get(id=request.GET['domain'], user=request.user, active=1)
form = DNSFormCNAME(initial={'ip': settings.MAIN_IP, 'type': request.GET['type'], 'host_end': DNS.objects.filter(domain=domain)})

I just want the zones that match that domain.. not all domains.

Answer 1

Initial data to a choice or foreign key field is used to determine what is selected in that field, not what the available options are. If you want to determine the list of options, you need to override the form's __init__ method and do it there.

class DNSFormCNAME(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        self.domain = kwargs.pop('domain', None)
        super(DNSFormCNAME, self).__init__(*args, **kwargs)
        if self.domain:
            self.fields['host_end'].queryset = DNS.objects.filter(domain=domain)