Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

# blog/serializers.py — DRF serializers
from rest_framework import serializers
from django.contrib.auth import get_user_model
from .models import Post, Tag, Category

User = get_user_model()

class TagSerializer(serializers.ModelSerializer):
    class Meta:
        model  = Tag
        fields = ['id', 'name', 'slug']

class AuthorSerializer(serializers.ModelSerializer):
    class Meta:
        model  = User
        fields = ['id', 'username', 'email']

class PostSerializer(serializers.ModelSerializer):
    author   = AuthorSerializer(read_only=True)
    tags     = TagSerializer(many=True, read_only=True)
    tag_ids  = serializers.PrimaryKeyRelatedField(
        queryset=Tag.objects.all(), many=True, write_only=True, source='tags',
    )
    url          = serializers.SerializerMethodField()
    reading_time = serializers.SerializerMethodField()

class Meta:
        model  = Post
        fields = [
            'id', 'title', 'slug', 'author', 'category',
            'body', 'tags', 'tag_ids', 'status',
            'published_at', 'url', 'reading_time',
        ]
        read_only_fields = ['slug', 'published_at']

def get_url(self, obj):
        request = self.context.get('request')
        return request.build_absolute_uri(f'/api/posts/{obj.pk}/')

def get_reading_time(self, obj):
        return max(1, round(len(obj.body.split()) / 200))

def validate_title(self, value):
        if len(value) < 5:
            raise serializers.ValidationError('Title must be at least 5 characters.')
        return value