drf-api-patterns

DRF API Patterns

Build production-grade REST APIs with Django REST Framework. DRF provides serialization, authentication, permissions, pagination, and more out of the box, so you write less boilerplate and get consistent API behavior.

When to Use

• User builds REST API endpoints in Django
• User needs serialization, validation, or pagination
• User implements authentication and permissions
• User asks about ViewSets, routers, or DRF best practices
• User needs filtering, search, or ordering on list endpoints

Core Patterns

Serializers

Serializers handle validation and conversion between Python objects and JSON.

from rest_framework import serializers

class ArticleSerializer(serializers.ModelSerializer):
    author_name = serializers.CharField(source="author.get_full_name", read_only=True)
    comment_count = serializers.IntegerField(read_only=True)
    tags = serializers.SlugRelatedField(
        many=True, slug_field="name", queryset=Tag.objects.all()
    )

    class Meta:
        model = Article
        fields = [
            "id", "title", "slug", "body", "status",
            "author", "author_name", "tags", "comment_count",
            "created_at", "updated_at",
        ]
        read_only_fields = ["id", "slug", "created_at", "updated_at"]

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

    def validate(self, attrs: dict) -> dict:
        """Cross-field validation."""
        if attrs.get("status") == "published" and not attrs.get("body"):
            raise serializers.ValidationError(
                {"body": "Published articles must have a body"}
            )
        return attrs

# Separate serializers for create vs read
class ArticleCreateSerializer(serializers.ModelSerializer):
    class Meta:
        model = Article
        fields = ["title", "body", "tags", "status"]

    def create(self, validated_data):
        tags = validated_data.pop("tags", [])
        article = Article.objects.create(
            author=self.context["request"].user,
            **validated_data,
        )
        article.tags.set(tags)
        return article