Django <object>不是JSON可序列化

Question

我正在使用https://github.com/coderholic/django-cities，我想为我的序列化程序添加城市和国家。

这是我的模型：

from cities.models import Country, City 

class Location(models.Model): 
    name = models.CharField(max_length=200, blank=True, null=True, default=None) 
    city = models.ForeignKey(City, blank=True, null=True, default=None, related_name='city_of_location') 
    geolocation = map_fields.GeoLocationField(max_length=100, blank=True, default='') 

我的观点：

class LocationsView(generics.ListAPIView): 
    queryset = Location.objects.order_by('-id') 
    serializer_class = LocationsSerializer 

serializers.py

class LocationsSerializer(serializers.ModelSerializer): 
    country = serializers.ReadOnlyField(source='city.country') 

    class Meta: 
     model = Location 
     fields = ['id', 'name', 'geolocation', 'city', 'country'] 

时，我想看看它是否工作我得到：

<Country: Austria> is not JSON serializable 

Answer 1

您需要定义CountrySerializer才能序列化嵌套关系。

class CountrySerializer(serializers.ModelSerializer): 
    class Meta: 
     model = Country 
     fields = '__all__' 

class LocationsSerializer(serializers.ModelSerializer): 
    number_of_rooms = serializers.SerializerMethodField() 
    country = CountrySerializer(source='city.country') 

    class Meta: 
     model = Location 
     fields = ['id', 'name', 'geolocation', 'city', 'country'] 

或者，如果你只需要国家ID，您可以使用PrimaryKeyRelatedField：

country = PrimaryKeyRelatedField(source='city.country')