Documentation

API documentation is essential for describing the functionality, endpoints, and usage of an API to developers and consumers. Django Rest Framework (DRF) provides built-in tools for generating API documentation, and there are several third-party libraries for more advanced features and customization.

DRF’s Built-in Documentation

DRF includes schema generation tools that can automatically generate OpenAPI or CoreAPI schemas, which are foundational for API documentation.

Schema Generation

1. Using the Built-in Schema Generator: DRF provides a schema generation framework via SchemaGenerator:

   • It creates an OpenAPI specification for the API.
   • Integrates seamlessly with DRF views, serializers, and permissions.

2. Adding Schema Views: Add a schema view to expose the API schema:

   from rest_framework.schemas import get_schema_view
   from django.urls import path
   
   schema_view = get_schema_view(title="My API")
   
   urlpatterns = [
       path('schema/', schema_view),
   ]

3. Customizing the Schema: Customize the schema generation by specifying:

   • Title
   • Description
   • Version

   schema_view = get_schema_view(
       title="My API",
       description="API documentation for My API",
       version="1.0.0"
   )

Built-in Browsable API

DRF’s browsable API provides interactive documentation by default, allowing developers to:

• Explore endpoints.
• Test API responses.
• View input fields and required data.

The browsable API is enabled by the BrowsableAPIRenderer in the DEFAULT_RENDERER_CLASSES setting.

Example of Built-in Schema

The schema endpoint (/schema/) returns an OpenAPI-compliant specification, which can be used with tools like Swagger or Postman.

Third-party Tools for Documentation

For more advanced and interactive API documentation, DRF integrates with third-party libraries such as drf-yasg and django-rest-swagger.

a. drf-yasg (Yet Another Swagger Generator)

drf-yasg is a powerful library for generating Swagger/OpenAPI documentation.

Installation:

pip install drf-yasg

Basic Setup: Add a schema view for Swagger and ReDoc documentation:

from drf_yasg.views import get_schema_view
from drf_yasg import openapi
from rest_framework.permissions import AllowAny
from django.urls import path

schema_view = get_schema_view(
    openapi.Info(
        title="My API",
        default_version='v1',
        description="API documentation for My API",
        terms_of_service="https://www.example.com/terms/",
        contact=openapi.Contact(email="contact@example.com"),
        license=openapi.License(name="BSD License"),
    ),
    public=True,
    permission_classes=(AllowAny,),
)

urlpatterns = [
    path('swagger/', schema_view.with_ui('swagger', cache_timeout=0), name='schema-swagger-ui'),
    path('redoc/', schema_view.with_ui('redoc', cache_timeout=0), name='schema-redoc'),
]

Features of drf-yasg:

• Interactive Swagger UI: Provides a user-friendly interface to test endpoints.
• ReDoc Integration: Generates clean, responsive documentation.
• Customizable: Supports overriding default schemas, descriptions, and parameters.

Customizing Endpoint Metadata: Use @swagger_auto_schema to customize schema details:

from drf_yasg.utils import swagger_auto_schema
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status

class MyAPIView(APIView):
    @swagger_auto_schema(
        operation_description="Retrieve data from the API",
        responses={200: "Success", 400: "Bad Request"}
    )
    def get(self, request):
        return Response({"message": "Success"}, status=status.HTTP_200_OK)

b. django-rest-swagger

django-rest-swagger was an earlier library for generating Swagger documentation. However, it is now deprecated in favor of drf-yasg. For legacy projects, it provides basic Swagger UI integration.

Installation:

pip install django-rest-swagger

Setup:

from rest_framework_swagger.views import get_swagger_view

schema_view = get_swagger_view(title="My API")

urlpatterns = [
    path('swagger/', schema_view),
]

Comparison of Documentation Tools

Feature	Built-in DRF Schema	drf-yasg	django-rest-swagger
Schema Type	OpenAPI	OpenAPI	Swagger (deprecated)
Interactive UI	No	Yes (Swagger & ReDoc)	Yes
Customization	Limited	Highly customizable	Limited
Support for Annotations	No	Yes	No
Maintenance	Actively supported	Actively supported	Deprecated

Best Practices for API Documentation

1. Keep Documentation Updated:

   • Use tools like drf-yasg to auto-generate documentation based on code.
   • Regularly review and update descriptions, examples, and details.

2. Write Detailed Descriptions:

   • Provide clear, concise descriptions for endpoints, parameters, and responses.
   • Include error scenarios and HTTP status codes.

3. Use Examples:

   • Show example requests and responses for clarity.
   • Include edge cases and common use cases.

4. Customize Where Needed:

   • Use custom schema overrides for non-standard endpoints.
   • Add human-readable descriptions for developers.

5. Host Documentation:

   • Expose Swagger or ReDoc documentation at a /docs/ endpoint.
   • Protect documentation with authentication if necessary for private APIs.

6. Automate Generation:

   • Integrate schema generation and validation into the CI/CD pipeline.