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