Django serialise nested object into json-CodePudding

I have two models:

modesl.py

class ForumSection(models.Model):
    title       = models.CharField(max_length=20)
    description = models.CharField(max_length=300)
    order       = models.IntegerField(default=0)
    
    def __str__(self):
        return self.title

class ForumSubSection(models.Model):
    section     = models.ForeignKey(ForumSection, on_delete=models.CASCADE)
    title       = models.CharField(max_length=20)
    description = models.CharField(max_length=300)
    order       = models.IntegerField(default=0)
    
    def __str__(self):
        return self.title

I try to serialize subsections to json and return to frontend:

def ajax_create_forum_subsection(request):
    .......
    sections = ForumSubSection.objects.all().order_by('pk')
    data = serialize("json", sections, fields=('pk', 'title', 'description', 'order', 'section'))
    return JsonResponse(data, safe=False)

But ``section``` return primary key (ID of record).

I'm readed 100500 questions on SA, some peoples say to write custom serializers.

ok, I'm write it.

serializers.py

from rest_framework import serializers
from .models import *

class ForumSectionSerializer(serializers.ModelSerializer):
    class Meta:
        model = ForumSection
        fields = '__all__'

    def create(validated_data):
        return ForumSection.objects.create(**validated_data)
      
class ForumSubSectionSerializer(serializers.ModelSerializer):
    section = ForumSectionSerializer(read_only=True)
   
    class Meta:
        model = ForumSubSection
        fields = ['pk', 'title', 'description', 'order', 'section']
        depth = 1

    def create(validated_data):
        return ForumSubSection.objects.create(**validated_data)

And try to use it.

def ajax_edit_forum_subsection(request):
    .......
    qs = ForumSubSection.objects.all().order_by('pk')
    ser = ForumSubSectionSerializer(qs)
    data = ser.serialize("json", qs, fields=('pk', 'title', 'description', 'order', 'section'))
    return JsonResponse(data, safe=False)

It call Server error 500 and not work.

Now is 5'th day of this problem and I write here to ask help.

How to serialize ForumSubSection objects with ForumSection objects?

CodePudding user response：

I think it should be:

def ajax_edit_forum_subsection(request):
    .......
    qs = ForumSubSection.objects.all().order_by('pk')
    ser = ForumSubSectionSerializer(qs, many=True)
    return JsonResponse(ser.data, safe=False)

CodePudding user response：

ser = ForumSubSectionSerializer(qs, many=True) already serializes the data for you. All you need to do is: get the data from it with ser.data or you may access the data directly from the class ForumSubSectionSerializer(qs, many=True).data.

def ajax_edit_forum_subsection(request):
    qs = ForumSubSection.objects.all().order_by('pk')
    ser = ForumSubSectionSerializer(qs, many=True).data # <- data here
    return JsonResponse(ser, safe=False)

Notice the many=Trye parameter. If a representation should be a list of items, you should pass the many=True flag to the serializer.