caching.md

Caching

A certain woman had a very sharp consciousness but almost no memory ... She remembered enough to work, and she worked hard.

• Lydia Davis

Caching in REST Framework works well with the cache utilities provided in Django.

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Using cache with apiview and viewsets

Django provides a method_decorator to use decorators with class based views. This can be used with other cache decorators such as cache_page, vary_on_cookie and vary_on_headers.

from django.utils.decorators import method_decorator
from django.views.decorators.cache import cache_page
from django.views.decorators.vary import vary_on_cookie, vary_on_headers

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


class UserViewSet(viewsets.ViewSet):
    # With cookie: cache requested url for each user for 2 hours
    @method_decorator(cache_page(60 * 60 * 2))
    @method_decorator(vary_on_cookie)
    def list(self, request, format=None):
        content = {
            "user_feed": request.user.get_user_feed(),
        }
        return Response(content)


class ProfileView(APIView):
    # With auth: cache requested url for each user for 2 hours
    @method_decorator(cache_page(60 * 60 * 2))
    @method_decorator(vary_on_headers("Authorization"))
    def get(self, request, format=None):
        content = {
            "user_feed": request.user.get_user_feed(),
        }
        return Response(content)


class PostView(APIView):
    # Cache page for the requested url
    @method_decorator(cache_page(60 * 60 * 2))
    def get(self, request, format=None):
        content = {
            "title": "Post title",
            "body": "Post content",
        }
        return Response(content)

Using cache with @api_view decorator

When using @api_view decorator, the Django-provided method-based cache decorators such as cache_page, vary_on_cookie and vary_on_headers can be called directly.

from django.views.decorators.cache import cache_page
from django.views.decorators.vary import vary_on_cookie

from rest_framework.decorators import api_view
from rest_framework.response import Response


@cache_page(60 * 15)
@vary_on_cookie
@api_view(['GET'])
def get_user_list(request):
    content = {
        'user_feed': request.user.get_user_feed()
    }
    return Response(content)

NOTE: The cache_page decorator only caches the GET and HEAD responses with status 200.