bookwyrm/bookwyrm/lists_stream.py
2022-01-07 13:30:11 -08:00

251 lines
9.2 KiB
Python

""" access the list streams stored in redis """
from django.dispatch import receiver
from django.db import transaction
from django.db.models import signals, Count, Q
from bookwyrm import models
from bookwyrm.redis_store import RedisStore
from bookwyrm.tasks import app, MEDIUM, HIGH
class ListsStream(RedisStore):
"""all the lists you can see"""
def stream_id(self, user): # pylint: disable=no-self-use
"""the redis key for this user's instance of this stream"""
if isinstance(user, int):
# allows the function to take an int or an obj
return f"{user}-lists"
return f"{user.id}-lists"
def get_rank(self, obj): # pylint: disable=no-self-use
"""lists are sorted by updated date"""
return obj.updated_date.timestamp()
def add_list(self, book_list):
"""add a list to users' feeds"""
# the pipeline contains all the add-to-stream activities
self.add_object_to_related_stores(book_list)
def add_user_lists(self, viewer, user):
"""add a user's lists to another user's feed"""
# only add the lists that the viewer should be able to see
lists = models.List.privacy_filter(viewer).filter(user=user)
self.bulk_add_objects_to_store(lists, self.stream_id(viewer))
def remove_user_lists(self, viewer, user, exclude_privacy=None):
"""remove a user's list from another user's feed"""
# remove all so that followers only lists are removed
lists = user.list_set
if exclude_privacy:
lists = lists.exclude(privacy=exclude_privacy)
self.bulk_remove_objects_from_store(lists.all(), self.stream_id(viewer))
def get_list_stream(self, user):
"""load the lists to be displayed"""
lists = self.get_store(self.stream_id(user))
return (
models.List.objects.filter(id__in=lists)
.annotate(item_count=Count("listitem", filter=Q(listitem__approved=True)))
# hide lists with no approved books
.filter(item_count__gt=0)
.select_related("user")
.prefetch_related("listitem_set")
.order_by("-updated_date")
.distinct()
)
def populate_lists(self, user):
"""go from zero to a timeline"""
self.populate_store(self.stream_id(user))
def get_audience(self, book_list): # pylint: disable=no-self-use
"""given a list, what users should see it"""
# everybody who could plausibly see this list
audience = models.User.objects.filter(
is_active=True,
local=True, # we only create feeds for users of this instance
).exclude( # not blocked
Q(id__in=book_list.user.blocks.all()) | Q(blocks=book_list.user)
)
group = book_list.group
# only visible to the poster and mentioned users
if book_list.privacy == "direct":
if group:
audience = audience.filter(
Q(id=book_list.user.id) # if the user is the post's author
| ~Q(groups=group.memberships) # if the user is in the group
)
else:
audience = audience.filter(
Q(id=book_list.user.id) # if the user is the post's author
)
# only visible to the poster's followers and tagged users
elif book_list.privacy == "followers":
if group:
audience = audience.filter(
Q(id=book_list.user.id) # if the user is the list's owner
| Q(following=book_list.user) # if the user is following the pwmer
# if a user is in the group
| Q(memberships__group__id=book_list.group.id)
)
else:
audience = audience.filter(
Q(id=book_list.user.id) # if the user is the list's owner
| Q(following=book_list.user) # if the user is following the pwmer
)
return audience.distinct()
def get_stores_for_object(self, obj):
return [self.stream_id(u) for u in self.get_audience(obj)]
def get_lists_for_user(self, user): # pylint: disable=no-self-use
"""given a user, what lists should they see on this stream"""
return models.List.privacy_filter(
user,
privacy_levels=["public", "followers"],
)
def get_objects_for_store(self, store):
user = models.User.objects.get(id=store.split("-")[0])
return self.get_lists_for_user(user)
@receiver(signals.post_save, sender=models.List)
# pylint: disable=unused-argument
def add_list_on_create(sender, instance, created, *args, **kwargs):
"""add newly created lists streamsstreams"""
if not created:
return
# when creating new things, gotta wait on the transaction
transaction.on_commit(lambda: add_list_on_create_command(instance.id))
@receiver(signals.post_delete, sender=models.List)
# pylint: disable=unused-argument
def remove_list_on_delete(sender, instance, *args, **kwargs):
"""remove deleted lists to streams"""
remove_list_task.delay(instance.id)
def add_list_on_create_command(instance_id):
"""runs this code only after the database commit completes"""
add_list_task.delay(instance_id)
@receiver(signals.post_save, sender=models.UserFollows)
# pylint: disable=unused-argument
def add_lists_on_follow(sender, instance, created, *args, **kwargs):
"""add a newly followed user's lists to feeds"""
if not created or not instance.user_subject.local:
return
add_user_lists_task.delay(instance.user_subject.id, instance.user_object.id)
@receiver(signals.post_delete, sender=models.UserFollows)
# pylint: disable=unused-argument
def remove_lists_on_unfollow(sender, instance, *args, **kwargs):
"""remove lists from a feed on unfollow"""
if not instance.user_subject.local:
return
# remove all but public lists
remove_user_lists_task.delay(
instance.user_subject.id, instance.user_object.id, exclude_privacy="public"
)
@receiver(signals.post_save, sender=models.UserBlocks)
# pylint: disable=unused-argument
def remove_lists_on_block(sender, instance, *args, **kwargs):
"""remove lists from all feeds on block"""
# blocks apply ot all feeds
if instance.user_subject.local:
remove_user_lists_task.delay(instance.user_subject.id, instance.user_object.id)
# and in both directions
if instance.user_object.local:
remove_user_lists_task.delay(instance.user_object.id, instance.user_subject.id)
@receiver(signals.post_delete, sender=models.UserBlocks)
# pylint: disable=unused-argument
def add_lists_on_unblock(sender, instance, *args, **kwargs):
"""add lists back to all feeds on unblock"""
# make sure there isn't a block in the other direction
if models.UserBlocks.objects.filter(
user_subject=instance.user_object,
user_object=instance.user_subject,
).exists():
return
# add lists back to streams with lists from anyone
if instance.user_subject.local:
add_user_lists_task.delay(
instance.user_subject.id,
instance.user_object.id,
)
# add lists back to streams with lists from anyone
if instance.user_object.local:
add_user_lists_task.delay(
instance.user_object.id,
instance.user_subject.id,
)
@receiver(signals.post_save, sender=models.User)
# pylint: disable=unused-argument
def populate_lists_on_account_create(sender, instance, created, *args, **kwargs):
"""build a user's feeds when they join"""
if not created or not instance.local:
return
transaction.on_commit(lambda: add_list_on_account_create_command(instance.id))
def add_list_on_account_create_command(user_id):
"""wait for the transaction to complete"""
populate_lists_task.delay(user_id)
# ---- TASKS
@app.task(queue=MEDIUM)
def populate_lists_task(user_id):
"""background task for populating an empty list stream"""
user = models.User.objects.get(id=user_id)
ListsStream().populate_lists(user)
@app.task(queue=MEDIUM)
def remove_list_task(list_id):
"""remove a list from any stream it might be in"""
stores = models.User.objects.filter(local=True, is_active=True).values_list(
"id", flat=True
)
# delete for every store
stores = [ListsStream().stream_id(idx) for idx in stores]
ListsStream().remove_object_from_related_stores(list_id, stores=stores)
@app.task(queue=HIGH)
def add_list_task(list_id):
"""add a list to any stream it should be in"""
book_list = models.List.objects.get(id=list_id)
ListsStream().add_list(book_list)
@app.task(queue=MEDIUM)
def remove_user_lists_task(viewer_id, user_id, exclude_privacy=None):
"""remove all lists by a user from a viewer's stream"""
viewer = models.User.objects.get(id=viewer_id)
user = models.User.objects.get(id=user_id)
ListsStream().remove_user_lists(viewer, user, exclude_privacy=exclude_privacy)
@app.task(queue=MEDIUM)
def add_user_lists_task(viewer_id, user_id):
"""add all lists by a user to a viewer's stream"""
viewer = models.User.objects.get(id=viewer_id)
user = models.User.objects.get(id=user_id)
ListsStream().add_user_lists(viewer, user)