Building REST APIs with Django REST Framework

Django REST Framework: The Complete Guide

Django REST Framework (DRF) is the gold standard for building web APIs in Python. It provides powerful serialization, flexible authentication, and browsable APIs out of the box.

Setting Up

pip install djangorestframework
pip install django-filter
pip install drf-spectacular  # OpenAPI documentation

Serializers

Serializers convert complex data types like Django querysets into Python data types that can be rendered as JSON. They also handle validation and deserialization.

from rest_framework import serializers
from .models import BlogPost

class BlogPostSerializer(serializers.ModelSerializer):
    author_name = serializers.CharField(source='author.username', read_only=True)
    like_count = serializers.SerializerMethodField()

    class Meta:
        model = BlogPost
        fields = ['id', 'title', 'slug', 'excerpt', 'content',
                  'author_name', 'like_count', 'published_date']
        read_only_fields = ['slug', 'published_date']

    def get_like_count(self, obj):
        return obj.likes.count()

    def validate_title(self, value):
        if len(value) < 10:
            raise serializers.ValidationError("Title must be at least 10 characters.")
        return value

ViewSets and Routers

from rest_framework import viewsets, permissions
from rest_framework.decorators import action
from rest_framework.response import Response

class BlogPostViewSet(viewsets.ModelViewSet):
    queryset = BlogPost.objects.filter(status='published')
    serializer_class = BlogPostSerializer
    permission_classes = [permissions.IsAuthenticatedOrReadOnly]
    filterset_fields = ['category', 'tags']
    search_fields = ['title', 'content']
    ordering_fields = ['published_date', 'views']

    @action(detail=True, methods=['post'])
    def like(self, request, pk=None):
        post = self.get_object()
        post.likes.get_or_create(user=request.user)
        return Response({'status': 'liked'})

Testing Your API

DRF includes a powerful test client. Always test your serializer validation, permissions, and edge cases.

Documentation

Use drf-spectacular to auto-generate OpenAPI 3.0 documentation. This gives you interactive Swagger UI and ReDoc pages that stay synchronized with your code.