Python Django Rest框架：嵌套序列化器动态模型字段

我定义了如下的序列化程序。我正在使用a动态更改显示字段

class SerializerTwo(serializers.ModelSerializer):

    class Meta:
        model = Two
        fields = ('name', 'contact_number')

class SerializerOne(DynamicFieldsModelSerializer, serializers.ModelSerializer):
    another_field = SerializerTwo()

    class Meta:
        lookup_field = 'uuid'
        model = One
        fields = ('status', 'another_field',)

现在我要做的是，动态地（动态地）传递SerializerWO中所有字段将使用的内容，就像我为SerializerOne所做的那样

我为Rone做这件事的方式是：

# where fields=('status')
SerializerOne(queryset, fields=fields)

是否有一种方法可以将SerializerWO中的字段添加到上述序列化程序初始化中

# where fields=('status', 'name') name from SerializerTwo
# the double underscore notation does not work here for fields, so another_field__name cannot be used as well
SerializerOne(queryset, fields=fields)

---

我使用以下方法实现所谓的

嵌套序列化器动态模型字段

class SerializerTwo(serializers.ModelSerializer):
    fields_filter_key = 'two_fields'
    class Meta:
        model = Two
        fields = ('name', 'contact_number')

class SerializerOne(DynamicFieldsModelSerializer, serializers.ModelSerializer):
    fields_filter_key = 'one_fields'
    another_field = serializers.SerializerMethodField()

    class Meta:
        lookup_field = 'uuid'
        model = One
        fields = ('status', 'another_field',)

    def get_another_field(self, obj):
        another_filed_serializer = SerializerTwo(obj.another_field, 
                                                 context=self.context)
        return another_filed_serializer.data 

我们对

DynamicFieldsModelSerializer

class DynamicFieldsModelSerializer(serializers.ModelSerializer):
    def __init__(self, *args, **kwargs):
        super(DynamicFieldsModelSerializer, self).__init__(*args, **kwargs)

        if 'request' not in self.context or not self.fields_filter_key:
            return
        fields = self.context['request'].query_params.get(self.fields_filter_key)
        if fields:
            fields = fields.split(',')
            allowed = set(fields)
            existing = set(self.fields.keys())
            for field_name in existing - allowed:
                self.fields.pop(field_name)

最后一个问题是如何组织url，像这样编写

GET

url：

---

domain/something？一个字段=姓名、联系电话和两个字段=另一个字段

在遇到同样的问题后，我找到了一个解决方案，我希望这将对一些人有所帮助。我根据定义修改了DynamicFieldsModelSerializer

之后，您可以这样使用它：

SerializerOne(queryset, nested={"another_field": ["name"]})

SerializerOne(instance, fields=["another_field__name"])

您可以修改我的解决方案以使用双下划线，而不是另一个带有dict的kewyord，但我想将常规字段与嵌套序列化程序分开

它也可以改进为递归，这里我只处理一个嵌套序列化程序的深度

编辑 毕竟，我修改了代码以使用双下划线语法：

def __init__(self, *args, **kwargs):

    def parse_nested_fields(fields):
        field_object = {"fields": []}
        for f in fields:
            obj = field_object
            nested_fields = f.split("__")
            for v in nested_fields:
                if v not in obj["fields"]:
                    obj["fields"].append(v)
                if nested_fields.index(v) < len(nested_fields) - 1:
                    obj[v] = obj.get(v, {"fields": []})
                    obj = obj[v]
        return field_object

    def select_nested_fields(serializer, fields):
        for k in fields:
            if k == "fields":
                fields_to_include(serializer, fields[k])
            else:
                select_nested_fields(serializer.fields[k], fields[k])

    def fields_to_include(serializer, fields):
        # Drop any fields that are not specified in the `fields` argument.
        allowed = set(fields)
        existing = set(serializer.fields.keys())
        for field_name in existing - allowed:
            serializer.fields.pop(field_name)

    # Don't pass the 'fields' arg up to the superclass
    fields = kwargs.pop('fields', None)
    # Instantiate the superclass normally
    super(DynamicFieldsModelSerializer, self).__init__(*args, **kwargs)

    if fields is not None:
        fields = parse_nested_fields(fields)
        # Drop any fields that are not specified in the `fields` argument.
        select_nested_fields(self, fields)

---

@Lotram的答案不适用于返回多个值的字段（通过

many=True

）

以下代码改进了@Lotram的解决方案，该解决方案适用于返回多个值的字段：

class NestedDynamicFieldsModelSerializer(serializers.ModelSerializer):

def __init__(self, *args, **kwargs):

    def parse_nested_fields(fields):
        field_object = {"fields": []}
        for f in fields:
            obj = field_object
            nested_fields = f.split("__")
            for v in nested_fields:
                if v not in obj["fields"]:
                    obj["fields"].append(v)
                if nested_fields.index(v) < len(nested_fields) - 1:
                    obj[v] = obj.get(v, {"fields": []})
                    obj = obj[v]
        return field_object

    def select_nested_fields(serializer, fields):
        for k in fields:
            if k == "fields":
                fields_to_include(serializer, fields[k])
            else:
                select_nested_fields(serializer.fields[k], fields[k])

    def fields_to_include(serializer, fields):
        # Drop any fields that are not specified in the `fields` argument.
        allowed = set(fields)
        if isinstance(serializer, serializers.ListSerializer):
            existing = set(serializer.child.fields.keys())
            for field_name in existing - allowed:
                serializer.child.fields.pop(field_name)
        else:
            existing = set(serializer.fields.keys())
            for field_name in existing - allowed:
                serializer.fields.pop(field_name)

    # Don't pass the 'fields' arg up to the superclass
    fields = kwargs.pop('fields', None)
    # Instantiate the superclass normally
    super(NestedDynamicFieldsModelSerializer, self).__init__(*args, **kwargs)

    if fields is not None:
        # import pdb; pdb.set_trace()
        fields = parse_nested_fields(fields)
        # Drop any fields that are not specified in the `fields` argument.
        select_nested_fields(self, fields)

类NestedDynamicFieldsModelSerializer（serializers.ModelSerializer）：
定义初始化（self，*args，**kwargs）：
def parse_嵌套_字段（字段）：
字段\对象={“字段”：[]}
对于字段中的f：
obj=字段\对象
嵌套的_字段=f.split（“uu”）
对于嵌套_字段中的v：
如果v不在obj[“字段”]：
obj[“字段”]。追加（v）
如果嵌套_字段。索引（v）

i将

fields=kwargs.pop（'fields'，None）

替换为

kwargs.get（'context'）.get（'request'）。如果是instance（kwargs.get（'context'），dict），则查询参数.get（'fields'），否则无

和

fields=parse_嵌套_字段（fields）

替换为

fields=parse_嵌套_字段（fields.split（'，'））

在

之后，如果字段不是None:

块

class NestedDynamicFieldsModelSerializer(serializers.ModelSerializer):

def __init__(self, *args, **kwargs):

    def parse_nested_fields(fields):
        field_object = {"fields": []}
        for f in fields:
            obj = field_object
            nested_fields = f.split("__")
            for v in nested_fields:
                if v not in obj["fields"]:
                    obj["fields"].append(v)
                if nested_fields.index(v) < len(nested_fields) - 1:
                    obj[v] = obj.get(v, {"fields": []})
                    obj = obj[v]
        return field_object

    def select_nested_fields(serializer, fields):
        for k in fields:
            if k == "fields":
                fields_to_include(serializer, fields[k])
            else:
                select_nested_fields(serializer.fields[k], fields[k])

    def fields_to_include(serializer, fields):
        # Drop any fields that are not specified in the `fields` argument.
        allowed = set(fields)
        if isinstance(serializer, serializers.ListSerializer):
            existing = set(serializer.child.fields.keys())
            for field_name in existing - allowed:
                serializer.child.fields.pop(field_name)
        else:
            existing = set(serializer.fields.keys())
            for field_name in existing - allowed:
                serializer.fields.pop(field_name)

    # Don't pass the 'fields' arg up to the superclass
    fields = kwargs.pop('fields', None)
    # Instantiate the superclass normally
    super(NestedDynamicFieldsModelSerializer, self).__init__(*args, **kwargs)

    if fields is not None:
        # import pdb; pdb.set_trace()
        fields = parse_nested_fields(fields)
        # Drop any fields that are not specified in the `fields` argument.
        select_nested_fields(self, fields)