Django REST Framework: Serializers & Views

Django REST Framework (DRF) adds powerful tools for building REST APIs on top of Django. Core concepts: Serializers (data validation + transformation), Views (request handling), and Routers (URL routing).

Setup

pip install djangorestframework

# settings.py
INSTALLED_APPS = [
    ...
    'rest_framework',
]

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': [
        'rest_framework.authentication.SessionAuthentication',
        'rest_framework.authentication.BasicAuthentication',
    ],
    'DEFAULT_PERMISSION_CLASSES': [
        'rest_framework.permissions.IsAuthenticated',
    ],
    'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
    'PAGE_SIZE': 10,
}

Serializers

from rest_framework import serializers
from .models import Article

# ModelSerializer — automatically maps model fields
class ArticleSerializer(serializers.ModelSerializer):
    author_name = serializers.SerializerMethodField()  # computed field

    class Meta:
        model = Article
        fields = ['id', 'title', 'content', 'author', 'author_name', 'created_at']
        read_only_fields = ['id', 'created_at', 'author']

    def get_author_name(self, obj):
        return obj.author.get_full_name()

    def validate_title(self, value):
        if len(value) < 5:
            raise serializers.ValidationError("Title too short.")
        return value

    def validate(self, attrs):
        # Cross-field validation
        if attrs.get('published') and not attrs.get('content'):
            raise serializers.ValidationError("Published articles must have content.")
        return attrs

    def create(self, validated_data):
        validated_data['author'] = self.context['request'].user
        return super().create(validated_data)

# Nested serializer
class CommentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Comment
        fields = ['id', 'text', 'created_at']

class ArticleDetailSerializer(ArticleSerializer):
    comments = CommentSerializer(many=True, read_only=True)

    class Meta(ArticleSerializer.Meta):
        fields = ArticleSerializer.Meta.fields + ['comments']

# Usage
serializer = ArticleSerializer(article)           # serialize single
serializer = ArticleSerializer(queryset, many=True)  # serialize list
serializer = ArticleSerializer(data=request.data)    # deserialize
if serializer.is_valid():
    serializer.save()
else:
    print(serializer.errors)

Class-Based Views

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status

class ArticleListView(APIView):
    def get(self, request):
        articles = Article.objects.all()
        serializer = ArticleSerializer(articles, many=True)
        return Response(serializer.data)

    def post(self, request):
        serializer = ArticleSerializer(data=request.data, context={'request': request})
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

class ArticleDetailView(APIView):
    def get_object(self, pk):
        try:
            return Article.objects.get(pk=pk)
        except Article.DoesNotExist:
            raise Http404

    def get(self, request, pk):
        article = self.get_object(pk)
        serializer = ArticleSerializer(article)
        return Response(serializer.data)

    def put(self, request, pk):
        article = self.get_object(pk)
        serializer = ArticleSerializer(article, data=request.data, context={'request': request})
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    def patch(self, request, pk):
        article = self.get_object(pk)
        serializer = ArticleSerializer(article, data=request.data, partial=True)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    def delete(self, request, pk):
        article = self.get_object(pk)
        article.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

# urls.py
urlpatterns = [
    path('articles/', ArticleListView.as_view()),
    path('articles/<int:pk>/', ArticleDetailView.as_view()),
]

Generic Views

from rest_framework import generics

# Pre-built CRUD views — less boilerplate
class ArticleListCreateView(generics.ListCreateAPIView):
    queryset = Article.objects.all()
    serializer_class = ArticleSerializer

    def get_queryset(self):
        # Dynamic filtering
        return Article.objects.filter(author=self.request.user)

class ArticleDetailView(generics.RetrieveUpdateDestroyAPIView):
    queryset = Article.objects.all()
    serializer_class = ArticleSerializer

# Other generics:
# ListAPIView, CreateAPIView
# RetrieveAPIView, UpdateAPIView, DestroyAPIView