Limit choices to foreignkey in django rest framework - django

Question

How to limit images of request.user to be linked with node. I wish I could do something like:
photo = models.ForeignKey(
Image,
limit_choices_to={'owner': username},
)
but request.user rather than username and I don't want to use local threads.
models.py
class Node(models.Model):
owner = models.ForeignKey(User)
content = models.TextField()
photo = models.ForeignKey(Image)
class Image(models.Model):
owner = models.ForeignKey(User)
file = models.ImageField(upload_to=get_upload_file_name)
serializers.py
class ImageSerializer(serializers.ModelSerializer):
owner = serializers.Field('owner.username')
class Meta:
model = Image
fields = ('file', 'owner')
class NodeSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Node
fields = ('content', 'photo', 'owner')

Answer 1

I would deal with this by overriding get_serializer_class to dynamically return a serializer class at runtime, setting the choices option on the field there:
def get_serializer_class(self, ...):
user = self.request.user
owner_choices = ... # However you want to restrict the choices
class ImageSerializer(serializers.ModelSerializer):
owner = serializers.Field('owner.username', choices=owner_choices)
class Meta:
model = Image
fields = ('file', 'owner')
return ImageSerializer

Answer 2

You can create a custom foreign key field and define get_queryset() method there to filter related objects to only those of your user. The current user can be retrieved from the request in the context:
class UserPhotoForeignKey(serializers.PrimaryKeyRelatedField):
def get_queryset(self):
return Image.objects.filter(owner=self.context['request'].user)
class NodeSerializer(serializers.HyperlinkedModelSerializer):
photo = UserPhotoForeignKey()
class Meta:
model = Node
fields = ('content', 'photo', 'owner')
This example is using Django REST Framework version 3.

Answer 3

class CustomForeignKey(serializers.PrimaryKeyRelatedField):
def get_queryset(self):
return Table.objects.filter(is_active=True)
class Serializer(serializers.ModelSerializer):
(...)
table= CustomForeignKey()
class Meta:
(...)
even more easy is :
class Serializer(serializers.ModelSerializer):
(...)
table = serializers.PrimaryKeyRelatedField(queryset=Table.objects.filter(is_active=True))
class Meta:
(...)

Answer 4

Because I am sure this logic will be used across an entire Django application why not make it more generic?
class YourPrimaryKeyRelatedField(serializers.PrimaryKeyRelatedField):
def __init__(self, **kwargs):
self.model = kwargs.pop('model')
assert hasattr(self.model, 'owner')
super().__init__(**kwargs)
def get_queryset(self):
return self.model.objects.filter(owner=self.context['request'].user)
serializers.py
class SomeModelSerializersWithABunchOfOwners(serializers.ModelSerializer):
photo = YourPrimaryKeyRelatedField(model=Photo)
categories = YourPrimaryKeyRelatedField(model=Category,
many=True)
# ...

Answer 5

from rest_framework import serializers
class CustomForeignKey(serializers.PrimaryKeyRelatedField):
def get_queryset(self):
return Table.objects.filter(user=self.context['request'].user)
# or: ...objects.filter(user=serializers.CurrentUserDefault()(self))
class Serializer(serializers.ModelSerializer):
table = CustomForeignKey()