如何添加新的序列化器字段以及所有模型字段？

Question

Here I have a model which has so many fields. So I want to use __all__ to return all the fields. But now I needed to add new field image_url so I customize a serializer like this but now with this I need to put all the model fields in the Meta class like this fields=['name','..', 'image_url'] in order to return the image_url .

Is there any way to return image_url without specifying it in the Meta.fields ? I mean I don't want to write all the model fields in the Meta.fields (since the fields are too many) and want to return the image_url also.

serializers.py

class MySerializer(ModelSerializer):
    image_url = serializers.SerializerMethodField('get_image_url')

    class Meta:
        model = MyModel
        fields = '__all__'
    def get_image_url(self, obj):
        return obj.image.url

Answer 1

You can try to subclass te serializer:

class MySerializer(ModelSerializer):

    class Meta:
        model = MyModel
        fields = '__all__'


class MyChildSerializer(MySerializer):

    image_url = serializers.SerializerMethodField()

    class Meta:
        fields = MySerializer.Meta.fields + ['image_url']

    def get_image_url(self, obj):
        return obj.image.url

Never tried something like this, but since Meta.fields is a list you can perform basic python operations on it.

ps. If you're using pattern get_<field_name> for getter, you do not need to specify it in SerializerMethodField arguments.

Answer 2

Try this:

class MySerializer(ModelSerializer):
    image_url = serializers.SerializerMethodField()

    class Meta:
        model = MyModel
        fields = [f.name for f in MyModel._meta.fields] + ['image_url']
    def get_image_url(self, obj):
        return obj.image.url