Best way to cache RESTful API results of GET calls

Question

I\'m thinking about the best way to create a cache layer in front or as first layer for GET requests to my RESTful API (written in Ruby).

Not every request can be ca

Answer 1

I’ve used redis successfully this way in my REST view:

from django.conf import settings
import hashlib
import json
from redis import StrictRedis
from django.utils.encoding import force_bytes

def get_redis():
    #get redis connection from RQ config in settings
    rc = settings.RQ_QUEUES['default']
    cache = StrictRedis(host=rc['HOST'], port=rc['PORT'], db=rc['DB'])
    return cache



class EventList(ListAPIView):
    queryset = Event.objects.all()
    serializer_class = EventSerializer
    renderer_classes = (JSONRenderer, )


    def get(self, request, format=None):
        if IsAdminUser not in self.permission_classes:  # dont cache requests from admins


            # make a key that represents the request results you want to cache
            #  your requirements may vary
            key = get_key_from_request()

            #  I find it useful to hash the key, when query parms are added
            #  I also preface event cache key with a string, so I can clear the cache
            #   when events are changed
            key = "todaysevents" + hashlib.md5(force_bytes(key)).hexdigest()        

            # I dont want any cache issues (such as not being able to connect to redis)
            #  to affect my end users, so I protect this section
            try:
                cache = get_redis()
                data = cache.get(key)
                if not data:
                    #  not cached, so perform standard REST functions for this view
                    queryset = self.filter_queryset(self.get_queryset())
                    serializer = self.get_serializer(queryset, many=True)
                    data = serializer.data

                    #  cache the data as a string
                    cache.set(key, json.dumps(data))

                    # manage the expiration of the cache 
                    expire = 60 * 60 * 2  
                    cache.expire(key, expire)
                else:
                    # this is the place where you save all the time
                    #  just return the cached data 
                    data = json.loads(data)

                return Response(data)
            except Exception as e:
                logger.exception("Error accessing event cache\n %s" % (e))

        # for Admins or exceptions, BAU
        return super(EventList, self).get(request, format)

in my Event model updates, I clear any event caches. This hardly ever is performed (only Admins create events, and not that often), so I always clear all event caches

class Event(models.Model):

...

    def clear_cache(self):
        try:
            cache = get_redis()
            eventkey = "todaysevents"
            for key in cache.scan_iter("%s*" % eventkey):
                cache.delete(key)
        except Exception as e:
            pass


    def save(self, *args, **kwargs):
        self.clear_cache()
        return super(Event, self).save(*args, **kwargs)