python - How to cache Django Rest Framework API calls?

32
votes

I'm using Memcached as backend to my django app. This code works fine in normal django query:

def get_myobj():
        cache_key = 'mykey'
        result = cache.get(cache_key, None)
        if not result:
            result = Product.objects.all().filter(draft=False)
            cache.set(cache_key, result)
        return result

But it doesn't work when used with django-rest-framework api calls:

class ProductListAPIView(generics.ListAPIView):
    def get_queryset(self):
        product_list = Product.objects.all()
        return product_list
    serializer_class = ProductSerializer

I'm about to try DRF-extensions which provide caching functionality:

https://github.com/chibisov/drf-extensions

but the build status on github is currently saying "build failing".

My app is very read-heavy on api calls. Is there a way to cache these calls?

Thank you.

2
pythondjangocachingdjango-rest-frameworkmemcached
Did you decorate the method with "@cache_response()" ? - Priyank Kapadia
Hi. @cache_response is from DRF-extensions which I haven't try implementing it yet because the build status says "build failing" on their github page : github.com/chibisov/drf-extensions - Kitti Wateesatogkij
You realize that the view you pasted doesn't call the cache ? - Linovia
Yes I modify values in admin and reload the drf web-browsable api. Values always changed after refresh. Default timeout should be 5 mins if my memory serves - Kitti Wateesatogkij
But product list on website does not change if refreshed within 5 mins interval. So I assume the cache is working(for website) - Kitti Wateesatogkij

2 Answers

53
votes

Ok, so, in order to use caching for your queryset:

class ProductListAPIView(generics.ListAPIView):
    def get_queryset(self):
        return get_myobj()
    serializer_class = ProductSerializer

You'd probably want to set a timeout on the cache set though (like 60 seconds):

cache.set(cache_key, result, 60)

If you want to cache the whole view:

from django.utils.decorators import method_decorator
from django.views.decorators.cache import cache_page

class ProductListAPIView(generics.ListAPIView):
    serializer_class = ProductSerializer

    @method_decorator(cache_page(60))
    def dispatch(self, *args, **kwargs):
        return super(ProductListAPIView, self).dispatch(*args, **kwargs)
1
votes

I just implemented this to use on my serializers

def cache_me(cache):
    def true_decorator(f):
        @wraps(f)
        def wrapper(*args, **kwargs):
            instance = args[1]
            cache_key = '%s.%s' % (instance.facility, instance.id)
            logger.debug('%s cache_key: %s' % (cache, cache_key))
            try:
                data = caches[cache].get(cache_key)
                if data is not None:
                    return data
            except:
                pass
            logger.info('did not cache')
            data = f(*args, **kwargs)
            try:
                caches[cache].set(cache_key, data)
            except:
                pass
            return data
        return wrapper
    return true_decorator

then i override the to_representation method on my serializers, so it caches the serialized output per instance.

class MyModelSerializer(serializers.ModelSerializer):

    class Meta:
        model = MyModel
        exclude = ('is_deleted', 'facility',)

    @cache_me('mymodel')
    def to_representation(self, instance):
       return super(MyModelSerializer, self).to_representation(instance)