Django REST Framework

Master Django REST Framework for building robust, scalable RESTful APIs with proper serialization and authentication.

Serializers

Build type-safe data serialization with Django REST Framework serializers.

from rest_framework import serializers
from django.contrib.auth.models import User

class UserSerializer(serializers.ModelSerializer):
    post_count = serializers.IntegerField(read_only=True)
    full_name = serializers.SerializerMethodField()

    class Meta:
        model = User
        fields = ['id', 'email', 'name', 'post_count', 'full_name']
        read_only_fields = ['id', 'created_at']
        extra_kwargs = {
            'email': {'required': True},
            'password': {'write_only': True}
        }

    def get_full_name(self, obj):
        return f"{obj.first_name} {obj.last_name}"

class PostSerializer(serializers.ModelSerializer):
    author = UserSerializer(read_only=True)
    author_id = serializers.IntegerField(write_only=True)

    class Meta:
        model = Post
        fields = '__all__'

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

    def validate(self, data):
        if data.get('published') and not data.get('content'):
            raise serializers.ValidationError('Published posts must have content')
        return data

    def create(self, validated_data):
        # Custom creation logic
        post = Post.objects.create(**validated_data)
        # Send notification, etc.
        return post

Custom Fields and Validation

Create custom serializer fields for complex data types.

from rest_framework import serializers

class Base64ImageField(serializers.ImageField):
    """Handle base64 encoded images."""

    def to_internal_value(self, data):
        import base64
        from django.core.files.base import ContentFile

        if isinstance(data, str) and data.startswith('data:image'):
            format, imgstr = data.split(';base64,')
            ext = format.split('/')[-1]
            data = ContentFile(base64.b64decode(imgstr), name=f'temp.{ext}')

        return super().to_internal_value(data)

class PostSerializer(serializers.ModelSerializer):
    image = Base64ImageField(required=False)

    class Meta:
        model = Post
        fields = ['id', 'title', 'image']

# Custom validators
def validate_no_profanity(value):
    profanity_words = ['bad', 'worse']
    if any(word in value.lower() for word in profanity_words):
        raise serializers.ValidationError('Content contains profanity')
    return value

class CommentSerializer(serializers.ModelSerializer):
    content = serializers.CharField(validators=[validate_no_profanity])

    class Meta:
        model = Comment
        fields = ['id', 'content', 'created_at']

Nested Serializers

Handle complex nested relationships.

class CommentSerializer(serializers.ModelSerializer):
    author = UserSerializer(read_only=True)

    class Meta:
        model = Comment
        fields = ['id', 'content', 'author', 'created_at']

class PostSerializer(serializers.ModelSerializer):
    author = UserSerializer(read_only=True)
    comments = CommentSerializer(many=True, read_only=True)

    class Meta:
        model = Post
        fields = ['id', 'title', 'content', 'author', 'comments']

# Writable nested serializers
class PostCreateSerializer(serializers.ModelSerializer):
    comments = CommentSerializer(many=True, required=False)

    class Meta:
        model = Post
        fields = ['id', 'title', 'content', 'comments']

    def create(self, validated_data):
        comments_data = validated_data.pop('comments', [])
        post = Post.objects.create(**validated_data)

        for comment_data in comments_data:
            Comment.objects.create(post=post, **comment_data)

        return post

# Dynamic nested serialization
class PostSerializer(serializers