详解从Django Rest Framework响应中删除空字段

框架(架构)  /  管理员 发布于 7年前   160

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：https://stackoverflow.com/questions/27015931/remove-null-fields-from-django-rest-framework-response

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