django rest framework limit_choices_to attribute ignored? - django

Question

I'm using the DjangoRest Framework with 2 models DeviceType and Channel. Now Channel has a ForeignKeyField pointing to a DeviceType. No problem so far.
But now I don't want all DeviceTypes to be selectable when adding or editing a Channel but only the DeviceTypes that have their usesChannels field set to True.
So I used the limit_Choices_to attribute but somehow that doesn't seem to work. No matter what I do, I alway get a list with all DeviceTypes including the ones with usesChannels set to False
This is my code:
models.py
class DeviceType(models.Model):
name = models.CharField(max_length=30)
usesChannels = models.BooleanField()
def __str__(self):
return '%s' % (self.name)
class Channel(models.Model):
type = models.ForeignKey(DeviceType, limit_choices_to={'usesChannels': True})
name = models.CharField(max_length=30)
channelNr = models.IntegerField()
serializers.py
class DeviceTypeSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = DeviceType
fields = ('url', 'name', 'usesChannels')
class ChannelSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Channel
flieds = ('url', 'type', 'name', 'channelNr')
I used the ForeignKey.limit_choices_to example from This link
Edit: I use the DRF browsable API to add, edit and remove data.
Answer: After struggling with this for a few days I found a working solution:
models.py
class DeviceType(models.Model):
name = models.CharField(max_length=30)
usesChannels = models.BooleanField()
def __str__(self):
return '%s' % (self.name)
class Channel(models.Model):
type = models.ForeignKey(DeviceType)
name = models.CharField(max_length=30)
channelNr = models.IntegerField()
serializers.py
class DeviceTypeSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = DeviceType
fields = ('url', 'name', 'usesChannels')
class ChannelSerializer(serializers.HyperlinkedModelSerializer):
type = serializers.PrimaryKeyRelatedField(queryset=DeviceType.objects.filter(usesChannels=True))
class Meta:
model = Channel
flieds = ('url', 'type', 'name', 'channelNr')
Edit: For completeness I'll add the views too
Views.py:
class DeviceTypeViewSet(viewsets.ModelViewSet):
queryset = DeviceType.objects.all()
serializer_class = DeviceTypeSerializer
class ChannelViewSet(viewsets.ModelViewSet):
queryset = Channel.objects.all()
serializer_class = ChannelSerializer

Answer 1

Ran into this problem today. I believe it does indeed completely ignore the attribute; at least I couldn't find any reference to it in DRF's code.
So I "solved" the problem by adding Serializer.__init__ constructor and within it the following function / code:
class MySerializer(Serializers.Serializer):
def __init__(self, *args, **kwargs):
...
def limit_choices_to(field_name):
fld = self.fields[field_name]
fld.queryset = fld.queryset.filter(**Flight._meta.get_field(field_name).get_limit_choices_to())
limit_choices_to('my_field')