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Django REST:如何防止特定模型字段的值被序列化?

django-rest-framework django python

barciewicz · 技术社区 · 6 年前

我有一个这样的模型:

class Test(models.Model):
    textjson = models.TextField(default="Unassigned")

田野 textjson 将JSON保存为字符串:

`'{"distance": 31702.1, "link": "www.strava.com/activities/2020494234", "athlete": 1, "average_speed": 6.499, "name": "Afternoon Ride", "start_date": "2018-12-16T12:13:42Z", "country": "Poland", "number": 2020494234, "date_added": "2018-12-16T20:14:01.362215Z"}`'

class ListTestsView(generics.ListAPIView):
    serializer_class = TestSerializer

    def get_queryset(self):
        tests = Test.objects.all()
        return tests

我把模型连载成这样:

class TestSerializer(serializers.ModelSerializer):
    class Meta:
        model = Test
        fields = '__all__'

jsontext 调用API视图并出现反斜杠时要再次序列化的字段:

[
    {
        "id": 1,
        "textjson": "{\"distance\": 31702.1, \"link\": \"www.strava.com/activities/2020494234\", \"athlete\": 1, \"average_speed\": 6.499, \"name\": \"Afternoon Ride\", \"start_date\": \"2018-12-16T12:13:42Z\", \"country\": \"Poland\", \"number\": 2020494234, \"date_added\": \"2018-12-16T20:14:01.362215Z\"}"
    }
]

如何重写 TestSerializer 仅用于防止的类这个价值属于要序列化的字段?

to_representation 和 to_internal_value

3 回复 | 直到 6 年前

barciewicz 6 年前

我已经找到办法了。需要编写自定义序列化程序字段并重写其 to representation 方法:

class CustomJSONField(serializers.Field):
    """Converts only value, not name, of a field into Javascript-friendly JSON,
     not Python object or backslashed JSON. Simply avoiding the field value,
     which is a string already, being serialized again"""
    def to_representation(self, value):
        return json.loads(value)

class TestSerializer(serializers.ModelSerializer):
    textjson = CustomJSONField()
    class Meta:
        model = Test
        fields = '__all__'

如果存储在字段中的JSON是字典列表的字符串表示,则可以执行以下操作:

import ast

class CustomJSONField(serializers.Field):
    def to_representation(self, value):
        return ast.literal_eval(value)

Ngoc Pham 6 年前

你可以定义 serializers.SerializerMethodField() textjson_original 如下所示:

    from rest_framework import serializers
    class TestSerializer(serializers.ModelSerializer):
        textjson_original = serializers.SerializerMethodField()
        @staticmethod
        def get_textjson_original(item):
            return item.textjson
        class Meta:
            model = Test
            fields = '__all__'

JPG 6 年前

使用 serializers.JSONField()

class TestSerializer(serializers.ModelSerializer):
    textjson = serializers.JSONField() # here &lt&lt&lt&lt&lt

    class Meta:
        model = Test
        fields = '__all__'