api.py 文件源码

def filter_popular(self, queryset, value):
        """
        Recommend content that is popular with all users.

        :param queryset: all content nodes for this channel
        :param value: id of currently logged in user, or none if user is anonymous
        :return: 10 most popular content nodes
        """
        if ContentSessionLog.objects.count() < 50:
            # return 25 random content nodes if not enough session logs
            pks = queryset.values_list('pk', flat=True).exclude(kind=content_kinds.TOPIC)
            # .count scales with table size, so can get slow on larger channels
            count_cache_key = 'content_count_for_popular'
            count = cache.get(count_cache_key) or min(pks.count(), 25)
            return queryset.filter(pk__in=sample(list(pks), count))

        cache_key = 'popular_content'
        if cache.get(cache_key):
            return cache.get(cache_key)

        # get the most accessed content nodes
        content_counts_sorted = ContentSessionLog.objects \
            .values_list('content_id', flat=True) \
            .annotate(Count('content_id')) \
            .order_by('-content_id__count')

        most_popular = queryset.filter(content_id__in=list(content_counts_sorted[:10]))

        # cache the popular results queryset for 10 minutes, for efficiency
        cache.set(cache_key, most_popular, 60 * 10)
        return most_popular