""" store recommended follows in redis """ import math import logging from django.dispatch import receiver from django.db.models import signals, Count, Q, Case, When, IntegerField from bookwyrm import models from bookwyrm.redis_store import RedisStore, r from bookwyrm.tasks import app logger = logging.getLogger(__name__) class SuggestedUsers(RedisStore): """suggested users for a user""" max_length = 30 def get_rank(self, obj): """get computed rank""" return obj.mutuals # + (1.0 - (1.0 / (obj.shared_books + 1))) def store_id(self, user): # pylint: disable=no-self-use """the key used to store this user's recs""" if isinstance(user, int): return f"{user}-suggestions" return f"{user.id}-suggestions" def get_counts_from_rank(self, rank): # pylint: disable=no-self-use """calculate mutuals count and shared books count from rank""" # pylint: disable=c-extension-no-member return { "mutuals": math.floor(rank), # "shared_books": int(1 / (-1 * (rank % 1 - 1))) - 1, } def get_objects_for_store(self, store): """a list of potential follows for a user""" user = models.User.objects.get(id=store.split("-")[0]) return get_annotated_users( user, ~Q(id=user.id), ~Q(followers=user), ~Q(follower_requests=user), bookwyrm_user=True, ) def get_stores_for_object(self, obj): return [self.store_id(u) for u in self.get_users_for_object(obj)] def get_users_for_object(self, obj): # pylint: disable=no-self-use """given a user, who might want to follow them""" return models.User.objects.filter(local=True,).exclude( Q(id=obj.id) | Q(followers=obj) | Q(id__in=obj.blocks.all()) | Q(blocks=obj) ) def rerank_obj(self, obj, update_only=True): """update all the instances of this user with new ranks""" pipeline = r.pipeline() for store_user in self.get_users_for_object(obj): annotated_user = get_annotated_users( store_user, id=obj.id, ).first() if not annotated_user: continue pipeline.zadd( self.store_id(store_user), self.get_value(annotated_user), xx=update_only, ) pipeline.execute() def rerank_user_suggestions(self, user): """update the ranks of the follows suggested to a user""" self.populate_store(self.store_id(user)) def remove_suggestion(self, user, suggested_user): """take a user out of someone's suggestions""" self.bulk_remove_objects_from_store([suggested_user], self.store_id(user)) def get_suggestions(self, user, local=False): """get suggestions""" values = self.get_store(self.store_id(user), withscores=True) annotations = [ When(pk=int(pk), then=self.get_counts_from_rank(score)["mutuals"]) for (pk, score) in values ] # annotate users with mutuals and shared book counts users = models.User.objects.filter( is_active=True, bookwyrm_user=True, id__in=[pk for (pk, _) in values] ).annotate(mutuals=Case(*annotations, output_field=IntegerField(), default=0)) if local: users = users.filter(local=True) return users.order_by("-mutuals")[:5] def get_annotated_users(viewer, *args, **kwargs): """Users, annotated with things they have in common""" return ( models.User.objects.filter(discoverable=True, is_active=True, *args, **kwargs) .exclude(Q(id__in=viewer.blocks.all()) | Q(blocks=viewer)) .annotate( mutuals=Count( "followers", filter=Q( ~Q(id=viewer.id), ~Q(id__in=viewer.following.all()), followers__in=viewer.following.all(), ), distinct=True, ), # pylint: disable=line-too-long # shared_books=Count( # "shelfbook", # filter=Q( # ~Q(id=viewer.id), # shelfbook__book__parent_work__in=[ # s.book.parent_work for s in viewer.shelfbook_set.all() # ], # ), # distinct=True, # ), ) ) suggested_users = SuggestedUsers() @receiver(signals.post_save, sender=models.UserFollows) # pylint: disable=unused-argument def update_suggestions_on_follow(sender, instance, created, *args, **kwargs): """remove a follow from the recs and update the ranks""" if not created or not instance.user_object.discoverable: return if instance.user_subject.local: remove_suggestion_task.delay(instance.user_subject.id, instance.user_object.id) rerank_user_task.delay(instance.user_object.id, update_only=False) @receiver(signals.post_save, sender=models.UserFollowRequest) # pylint: disable=unused-argument def update_suggestions_on_follow_request(sender, instance, created, *args, **kwargs): """remove a follow from the recs and update the ranks""" if not created or not instance.user_object.discoverable: return if instance.user_subject.local: remove_suggestion_task.delay(instance.user_subject.id, instance.user_object.id) @receiver(signals.post_save, sender=models.UserBlocks) # pylint: disable=unused-argument def update_suggestions_on_block(sender, instance, *args, **kwargs): """remove blocked users from recs""" if instance.user_subject.local and instance.user_object.discoverable: remove_suggestion_task.delay(instance.user_subject.id, instance.user_object.id) if instance.user_object.local and instance.user_subject.discoverable: remove_suggestion_task.delay(instance.user_object.id, instance.user_subject.id) @receiver(signals.post_delete, sender=models.UserFollows) # pylint: disable=unused-argument def update_suggestions_on_unfollow(sender, instance, **kwargs): """update rankings, but don't re-suggest because it was probably intentional""" if instance.user_object.discoverable: rerank_user_task.delay(instance.user_object.id, update_only=False) # @receiver(signals.post_save, sender=models.ShelfBook) # @receiver(signals.post_delete, sender=models.ShelfBook) # # pylint: disable=unused-argument # def update_rank_on_shelving(sender, instance, *args, **kwargs): # """when a user shelves or unshelves a book, re-compute their rank""" # # if it's a local user, re-calculate who is rec'ed to them # if instance.user.local: # rerank_suggestions_task.delay(instance.user.id) # # # if the user is discoverable, update their rankings # if instance.user.discoverable: # rerank_user_task.delay(instance.user.id) @receiver(signals.post_save, sender=models.User) # pylint: disable=unused-argument, too-many-arguments def update_user(sender, instance, created, update_fields=None, **kwargs): """an updated user, neat""" # a new user is found, create suggestions for them if created and instance.local: rerank_suggestions_task.delay(instance.id) # we know what fields were updated and discoverability didn't change if not instance.bookwyrm_user or ( update_fields and not "discoverable" in update_fields ): return # deleted the user if not created and not instance.is_active: remove_user_task.delay(instance.id) return # this happens on every save, not just when discoverability changes, annoyingly if instance.discoverable: rerank_user_task.delay(instance.id, update_only=False) elif not created: remove_user_task.delay(instance.id) @receiver(signals.post_save, sender=models.FederatedServer) def domain_level_update(sender, instance, created, update_fields=None, **kwargs): """remove users on a domain block""" if ( not update_fields or "status" not in update_fields or instance.application_type != "bookwyrm" ): return if instance.status == "blocked": bulk_remove_instance_task.delay(instance.id) return bulk_add_instance_task.delay(instance.id) # ------------------- TASKS @app.task(queue="low_priority") def rerank_suggestions_task(user_id): """do the hard work in celery""" suggested_users.rerank_user_suggestions(user_id) @app.task(queue="low_priority") def rerank_user_task(user_id, update_only=False): """do the hard work in celery""" user = models.User.objects.get(id=user_id) suggested_users.rerank_obj(user, update_only=update_only) @app.task(queue="low_priority") def remove_user_task(user_id): """do the hard work in celery""" user = models.User.objects.get(id=user_id) suggested_users.remove_object_from_related_stores(user) @app.task(queue="medium_priority") def remove_suggestion_task(user_id, suggested_user_id): """remove a specific user from a specific user's suggestions""" suggested_user = models.User.objects.get(id=suggested_user_id) suggested_users.remove_suggestion(user_id, suggested_user) @app.task(queue="low_priority") def bulk_remove_instance_task(instance_id): """remove a bunch of users from recs""" for user in models.User.objects.filter(federated_server__id=instance_id): suggested_users.remove_object_from_related_stores(user) @app.task(queue="low_priority") def bulk_add_instance_task(instance_id): """remove a bunch of users from recs""" for user in models.User.objects.filter(federated_server__id=instance_id): suggested_users.rerank_obj(user, update_only=False)