当我使用to_representation
时出现错误:
django.db.models.fields.related_descriptors.RelatedObjectDoesNotExist:SwitchesPort没有物理服务器。
追溯如下:
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/rest_framework/serializers.py", line 656, in <listcomp>
self.child.to_representation(item) for item in iterable
File "/Users/asd/Desktop/xxx/api/serializers.py", line 256, in to_representation
if instance.physical_server == None:
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/db/models/fields/related_descriptors.py", line 407, in __get__
self.related.get_accessor_name()
django.db.models.fields.related_descriptors.RelatedObjectDoesNotExist: SwitchesPort has no physical_server.
我的模特:
class SwitchesPort(models.Model):
"""
交换机接口
"""
...
switches = models.ForeignKey(to=Switches, on_delete=models.CASCADE,related_name="switchesports", help_text="所属交换机")
vlanedipv4networkgroup = models.ForeignKey(
to=VlanedIPv4NetworkGroup, # 初始化之后的
null=True,
blank=True,
on_delete=models.SET_NULL,
related_name="switchesports",
help_text="所关联的vlaned组")
network_speed = models.IntegerField(default=10, help_text="交换机控制网络流量速度")
class Meta:
ordering = ['name']
def __str__(self):
return self.name
def __unicode__(self):
return self.name
class PhysicalServer(models.Model):
"""
physical_server
"""
...
switchesport = models.OneToOneField(to=SwitchesPort, related_name="physical_server", on_delete=models.DO_NOTHING, help_text="所属交换机接口",
null=True)
def __str__(self):
return self.name
def __unicode__(self):
return self.name
我的序列化器如下所示:
class SwitchesPortSerializer(ModelSerializer):
"""
switches port
"""
class Meta:
model = SwitchesPort
fields = "__all__"
extra_kwargs = {
"vlaned_network":{"read_only":True}
}
def to_representation(self, instance):
serialized_data = super(SwitchesPortSerializer, self).to_representation(instance)
if instance.physical_server == None: # there syas the error
serialized_data['is_connected'] = True
return serialized_data
您会看到,OneToOne字段具有
related_name
,为什么我仍然遇到问题? 最佳答案
if instance.physical_server == None:
这将不起作用,因为如果该实例没有相关的
instance.physical_server
,则PhysicalServer
将引发异常您可以通过将支票更改为以下内容来解决此问题:
if hasattr(instance, 'physical_server'):
有关更多信息,请参见one-to-one relationships上的文档。