详解从Django Rest Framework响应中删除空字段

我使用django-rest-framework开发了一个api.

我正在使用modelserializer返回模型的数据.

models.py

class metatags(models.model):
 title = models.charfield(_('title'), max_length=255, blank=true, null=true)
 name = models.charfield(_('name'), max_length=255, blank=true, null=true)

serializer.py

class metatagsserializer(serializers.modelserializer):
 class meta:
  model = metatags

响应

{
 "meta": {
  "title": null,
  "name": "xyz"
 }
}

理想情况下,在api响应中,不应在响应中发送任何不存在的值.

当标题为null时,我希望响应为：

{
 "meta": {
  "name": "xyz"
 }
}

您可以尝试覆盖to_native函数：

class metatagsserializer(serializers.modelserializer):
 class meta:
  model = metatags

 def to_native(self, obj):
  """
  serialize objects -> primitives.
  """
  ret = self._dict_class()
  ret.fields = self._dict_class()

  for field_name, field in self.fields.items():
   if field.read_only and obj is none:
    continue
   field.initialize(parent=self, field_name=field_name)
   key = self.get_field_key(field_name)
   value = field.field_to_native(obj, field_name)

   # continue if value is none so that it does not get serialized.
   if value is none:
    continue

   method = getattr(self, 'transform_%s' % field_name, none)
   if callable(method):
    value = method(obj, value)
   if not getattr(field, 'write_only', false):
    ret[key] = value
   ret.fields[key] = self.augment_field(field, field_name, key, value)

  return ret

我基本上从serializers.baseserializer复制了基本的to_native函数,并添加了一个值的检查.

更新：

至于drf 3.0,to_native()被重命名为to_representation(),其实现稍有改变.这是drf 3.0的代码,它忽略空值和空字符串值：

def to_representation(self, instance):
 """
 object instance -> dict of primitive datatypes.
 """
 ret = ordereddict()
 fields = self._readable_fields

 for field in fields:
  try:
   attribute = field.get_attribute(instance)
  except skipfield:
   continue

  # key is here:
  if attribute in [none, '']:
   continue

  # we skip `to_representation` for `none` values so that fields do
  # not have to explicitly deal with that case.
  #
  # for related fields with `use_pk_only_optimization` we need to
  # resolve the pk value.
  check_for_none = attribute.pk if isinstance(attribute, pkonlyobject) else attribute
  if check_for_none is none:
   ret[field.field_name] = none
  else:
   ret[field.field_name] = field.to_representation(attribute)

 return ret

翻译自：

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