序列化器不可序列化数据的全部捕获字段

Question

. Answers to this question are eligible for a +50 reputation bounty. finngu wants to to this question:

Please help me in writing a django serializer that stores fields that could not be validated in a JSONField. I would like the serializer to be somewhat generic, because it needs to process many fields and I do not want to copy paste every single one.

I have a route where meta-data can be POSTed. If known fields are POSTed, I would like to store them in a structured manner in my DB, only storing unknown fields or fields that fail validation in a JSONField .

Let's assume my model to be:

# models.py
from django.db import models


class MetaData(models.Model):
  shipping_address_zip_code = models.CharField(max_length=5, blank=True, null=True)
  ...
  unparseable_info = models.JSONField(blank=True, null=True)

I would like to use the built-in serialisation logic to validate whether a zip_code is valid (5 letters or less). If it is, I would proceed normally and store it in the shipping_address_zip_code field. If it fails validation however, I would like to store it as a key-value-pair in the unparseable_info field and still return a success message to the client calling the route.

I have many more fields and am looking for a generic solution, but only including one field here probably helps in illustrating my problem.

Answer 1

 def validate_shipping_address_zip_code(self, value):
      if value >= 5:
        return value
      else:
          raise serializers.ValidationError("Message Here")

there's much more validators in serializer look into more detail https://www.django-rest-framework.org/api-guide/serializers/

Answer 2

from rest_framework import serializers
class MetaDataSerializer(serializers.ModelSerializer):
    unparseable_info = serializers.JSONField(required=False)
    class Meta:
        model = MetaData
        fields = ('shipping_address_zip_code', 'unparseable_info')
    
    def validate_shipping_address_zip_code(self, value):
        if len(value) > 5:
            raise serializers.ValidationError("Zip code is too long")
        return value
    
    def create(self, validated_data):
        unparseable_info = {}
        for key, value in self.initial_data.items():
            try:
                validated_data[key] = self.fields[key].run_validation(value)
            except serializers.ValidationError as exc:
                unparseable_info[key] = value
                validated_data.pop(key, None)
    
        instance = MetaData.objects.create(**validated_data)
    
        if unparseable_info:
            instance.unparseable_info = unparseable_info
            instance.save()
    
        return instance