Django — Serializers

Basic Serializer

from rest_framework import serializers
from .models import Post

class PostSerializer(serializers.ModelSerializer):
    class Meta:
        model = Post
        fields = ['id', 'title', 'content', 'author', 'created_at']

Field Types

Field	Description
CharField	String
IntegerField	Integer
BooleanField	Boolean
DateTimeField	DateTime
EmailField	Email
SlugField	Slug
FileField	File
ImageField	Image
ForeignKey	Related object

Validation

class PostSerializer(serializers.ModelSerializer):
    def validate_title(self, value):
        if len(value) < 5:
            raise serializers.ValidationError("Title too short")
        return value
    
    def validate(self, data):
        if data['title'] == data['content']:
            raise serializers.ValidationError("Title and content differ")
        return data

Nested Serializers

class AuthorSerializer(serializers.ModelSerializer):
    class Meta:
        model = Author
        fields = ['id', 'name']

class PostSerializer(serializers.ModelSerializer):
    author = AuthorSerializer(read_only=True)
    
    class Meta:
        model = Post
        fields = ['id', 'title', 'content', 'author']

Custom Fields

class PostSerializer(serializers.ModelSerializer):
    word_count = serializers.SerializerMethodField()
    
    def get_word_count(self, obj):
        return len(obj.content.split())

Mini Practice

1. Create a basic serializer
2. Add field validation
3. Use nested serializers
4. Create custom fields

Up Next

Continue with ViewSets — combining views and serializers.