In my app I have the following models:

class Zone(models.Model):
    name = models.SlugField()

class ZonePermission(models.Model):
    zone = models.ForeignKey('Zone')
    user = models.ForeignKey(User)
    is_administrator = models.BooleanField()
    is_active = models.BooleanField()

I am using Django REST framework to create a resource that returns zone details plus a nested resource showing the authenticated user's permissions for that zone. The output should be something like this:

{
    "name": "test", 
    "current_user_zone_permission": {
        "is_administrator": true, 
        "is_active": true
    }
} 

I've created serializers like so:

class ZonePermissionSerializer(serializers.ModelSerializer):
    class Meta:
        model = ZonePermission
        fields = ('is_administrator', 'is_active')

class ZoneSerializer(serializers.HyperlinkedModelSerializer):
    current_user_zone_permission = ZonePermissionSerializer(source='zonepermission_set')

    class Meta:
        model = Zone
        fields = ('name', 'current_user_zone_permission')

The problem with this is that when I request a particular zone, the nested resource returns the ZonePermission records for all the users with permissions for that zone. Is there any way of applying a filter on request.user to the nested resource?

BTW I don't want to use a HyperlinkedIdentityField for this (to minimise http requests).

Solution

This is the solution I implemented based on the answer below. I added the following code to my serializer class:

current_user_zone_permission = serializers.SerializerMethodField('get_user_zone_permission')

def get_user_zone_permission(self, obj):
    user = self.context['request'].user
    zone_permission = ZonePermission.objects.get(zone=obj, user=user)
    serializer = ZonePermissionSerialize