我正在为一个uni项目开发一个Web应用程序,它是关于机场和运营商......
问题是,当我尝试以并行方式提供给数据库时,因为在我使用的json文件中有很多关于运营商和机场的条目。
当您按顺序逐个更新(PUT和PATCH)时,它正在按预期工作,但是当我尝试PUT / PATCH并行请求时,每次都会覆盖DB中的实例。
每个机场都有一个运营商列表,当我尝试通过PUT或PATCH以并行方式向该列表添加更多运营商时,它会覆盖实例以前的运营商列表
我的模特是:
class Carrier(models.Model):
code = models.CharField(max_length=10, primary_key=True)
name = models.TextField()
def __str__(self):
return self.name
class Airport(models.Model):
code = models.CharField(max_length=10, primary_key=True)
name = models.TextField()
carriers = models.ManyToManyField(Carrier, related_name='airports')
def __str__(self):
return self.name
串行器:
class AirportListSerializer(serializers.ModelSerializer):
url = serializers.HyperlinkedIdentityField(view_name='airport-detail')
class Meta:
model = models.Airport
fields = ('code', 'name', 'url')
class AirportDetailSerializer(serializers.ModelSerializer):
url = serializers.HyperlinkedIdentityField(view_name='airport-detail')
class Meta:
model = models.Airport
fields = ('code', 'name', 'url', 'carriers')
而我的更新方法遇到问题我必须覆盖它,因为要将新数据附加到机场实例的运营商数组中:
def update(self, request, *args, **kwargs):
instance = self.get_object()
serializer = serializers.AirportDetailSerializer(
instance=instance,
data=request.data,
context={'request': request}
)
if serializer.is_valid(raise_exception=True):
# Getting the user inputed carriers after it was validated by the serializer
carriers = set(dict(request.data)['carriers'])
# Adding new carriers to the current airport list of carriers without deleting the old ones
for carrier in serializer.validated_data['carriers']:
print(carrier)
carriers.add(carrier)
print('Carriers %s' % carriers)
# Saving alterations to the db
serializer.save(carriers=carriers)
# Overriding the original data for more features
data = serializer.data
# Creating the carrier links
data['carriers'] = ['http://%s/api/carriers/%s/' % (request.get_host(), carrier) for carrier in data['carriers']]
return Response(data)
每次调用serializer.save(carriers=carriers)
时,只使用特定PUT / PATCH请求中的载波保存Airport
实例...而不是将载波添加到Airport
实例中。
您应该查看writable nested serializers的文档并使用单独的CarrierSerializer
。
在相关的说明,你的update
逻辑更适合作为AirportSerializer
的一部分,而不是你的观点。这使它更具可重用性。 DRF文档的这一部分是您的完美示例。
像这个伪代码改编自Albums / Tracks示例:
class AirportSerializer(serializers.ModelSerializer):
carriers = CarrierSerializer(many=True)
class Meta:
model = Airport
fields = ......
def update(self, instance, validated_data):
carriers_data = validated_data.pop('carriers')
for carrier in carriers_data:
Carrier.objects.update_or_create(airport=instance, defaults=carrier_data)
return instance