takahe/users/models/block.py

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import datetime
from typing import Optional
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import httpx
from django.db import models, transaction
from django.utils import timezone
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from core.ld import canonicalise, get_str_or_id
from stator.models import State, StateField, StateGraph, StatorModel
from users.models.identity import Identity
class BlockStates(StateGraph):
new = State(try_interval=600)
sent = State(externally_progressed=True)
awaiting_expiry = State(try_interval=60 * 60, attempt_immediately=False)
undone = State(try_interval=60 * 60, delete_after=86400 * 7)
undone_sent = State(delete_after=86400)
new.transitions_to(sent)
new.transitions_to(awaiting_expiry)
sent.transitions_to(undone)
awaiting_expiry.transitions_to(undone)
# We don't really care if the other end accepts our block
new.times_out_to(sent, seconds=86400 * 7)
undone.transitions_to(undone_sent)
@classmethod
def group_active(cls):
return [cls.new, cls.sent, cls.awaiting_expiry]
@classmethod
async def handle_new(cls, instance: "Block"):
"""
Block that are new need us to deliver the Block object
to the target server.
"""
# Mutes don't send but might need expiry
if instance.mute:
return cls.awaiting_expiry
# Fetch more info
block = await instance.afetch_full()
# Remote blocks should not be here, local blocks just work
if not block.source.local or block.target.local:
return cls.sent
# Don't try if the other identity didn't fetch yet
if not block.target.inbox_uri:
return
# Sign it and send it
try:
await block.source.signed_request(
method="post",
uri=block.target.inbox_uri,
body=canonicalise(block.to_ap()),
)
except httpx.RequestError:
return
return cls.sent
@classmethod
async def handle_awaiting_expiry(cls, instance: "Block"):
"""
Checks to see if there is an expiry we should undo
"""
if instance.expires and instance.expires <= timezone.now():
return cls.undone
@classmethod
async def handle_undone(cls, instance: "Block"):
"""
Delivers the Undo object to the target server
"""
block = await instance.afetch_full()
# Remote blocks should not be here, mutes don't send, local blocks just work
if not block.source.local or block.target.local or instance.mute:
return cls.undone_sent
try:
await block.source.signed_request(
method="post",
uri=block.target.inbox_uri,
body=canonicalise(block.to_undo_ap()),
)
except httpx.RequestError:
return
return cls.undone_sent
class BlockQuerySet(models.QuerySet):
def active(self):
query = self.filter(state__in=BlockStates.group_active())
return query
class BlockManager(models.Manager):
def get_queryset(self):
return BlockQuerySet(self.model, using=self._db)
def active(self):
return self.get_queryset().active()
class Block(StatorModel):
"""
When one user (the source) mutes or blocks another (the target)
"""
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state = StateField(BlockStates)
source = models.ForeignKey(
"users.Identity",
on_delete=models.CASCADE,
related_name="outbound_blocks",
)
target = models.ForeignKey(
"users.Identity",
on_delete=models.CASCADE,
related_name="inbound_blocks",
)
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uri = models.CharField(blank=True, null=True, max_length=500)
# If it is a mute, we will stop delivering any activities from target to
# source, but we will still deliver activities from source to target.
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# A full block (mute=False) stops activities both ways.
mute = models.BooleanField()
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include_notifications = models.BooleanField(default=False)
expires = models.DateTimeField(blank=True, null=True)
note = models.TextField(blank=True, null=True)
created = models.DateTimeField(auto_now_add=True)
updated = models.DateTimeField(auto_now=True)
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objects = BlockManager()
class Meta:
unique_together = [("source", "target", "mute")]
def __str__(self):
return f"#{self.id}: {self.source} blocks {self.target}"
### Alternate fetchers/constructors ###
@classmethod
def maybe_get(
cls, source, target, mute=False, require_active=False
) -> Optional["Block"]:
"""
Returns a Block if it exists between source and target
"""
try:
if require_active:
return cls.objects.active().get(source=source, target=target, mute=mute)
else:
return cls.objects.get(source=source, target=target, mute=mute)
except cls.DoesNotExist:
return None
@classmethod
def create_local_block(cls, source, target) -> "Block":
"""
Creates or updates a full Block from a local Identity to the target
(which can be local or remote).
"""
if not source.local:
raise ValueError("You cannot block from a remote Identity")
block = cls.maybe_get(source=source, target=target, mute=False)
if block is not None:
if not block.active:
block.state = BlockStates.new # type:ignore
block.save()
else:
with transaction.atomic():
block = cls.objects.create(
source=source,
target=target,
mute=False,
)
block.uri = source.actor_uri + f"block/{block.pk}/"
block.save()
return block
@classmethod
def create_local_mute(
cls,
source,
target,
duration=None,
include_notifications=False,
) -> "Block":
"""
Creates or updates a muting Block from a local Identity to the target
(which can be local or remote).
"""
if not source.local:
raise ValueError("You cannot mute from a remote Identity")
block = cls.maybe_get(source=source, target=target, mute=True)
if block is not None:
if not block.active:
block.state = BlockStates.new # type:ignore
if duration:
block.expires = timezone.now() + datetime.timedelta(seconds=duration)
block.include_notifications = include_notifications
block.save()
else:
with transaction.atomic():
block = cls.objects.create(
source=source,
target=target,
mute=True,
include_notifications=include_notifications,
expires=(
timezone.now() + datetime.timedelta(seconds=duration)
if duration
else None
),
)
block.uri = source.actor_uri + f"block/{block.pk}/"
block.save()
return block
### Properties ###
@property
def active(self):
return self.state in BlockStates.group_active()
### Async helpers ###
async def afetch_full(self):
"""
Returns a version of the object with all relations pre-loaded
"""
return await Block.objects.select_related(
"source", "source__domain", "target"
).aget(pk=self.pk)
### ActivityPub (outbound) ###
def to_ap(self):
"""
Returns the AP JSON for this object
"""
if self.mute:
raise ValueError("Cannot send mutes over ActivityPub")
return {
"type": "Block",
"id": self.uri,
"actor": self.source.actor_uri,
"object": self.target.actor_uri,
}
def to_undo_ap(self):
"""
Returns the AP JSON for this objects' undo.
"""
return {
"type": "Undo",
"id": self.uri + "#undo",
"actor": self.source.actor_uri,
"object": self.to_ap(),
}
### ActivityPub (inbound) ###
@classmethod
def by_ap(cls, data: str | dict, create=False) -> "Block":
"""
Retrieves a Block instance by its ActivityPub JSON object or its URI.
Optionally creates one if it's not present.
Raises KeyError if it's not found and create is False.
"""
# If it's a string, do the reference resolve
if isinstance(data, str):
bits = data.strip("/").split("/")
if bits[-2] != "block":
raise ValueError(f"Unknown Block object URI: {data}")
return Block.objects.get(pk=bits[-1])
# Otherwise, do the object resolve
else:
# Resolve source and target and see if a Block exists
source = Identity.by_actor_uri(data["actor"], create=create)
target = Identity.by_actor_uri(get_str_or_id(data["object"]))
block = cls.maybe_get(source=source, target=target, mute=False)
# If it doesn't exist, create one in the sent state
if block is None:
if create:
return cls.objects.create(
source=source,
target=target,
uri=data["id"],
mute=False,
state=BlockStates.sent,
)
else:
raise cls.DoesNotExist(
f"No block with source {source} and target {target}", data
)
else:
return block
@classmethod
def handle_ap(cls, data):
"""
Handles an incoming Block notification
"""
with transaction.atomic():
cls.by_ap(data, create=True)
@classmethod
def handle_undo_ap(cls, data):
"""
Handles an incoming Block Undo
"""
# Resolve source and target and see if a Follow exists (it hopefully does)
try:
block = cls.by_ap(data["object"])
except KeyError:
raise ValueError("No Block locally for incoming Undo", data)
# Check the block's source is the actor
if data["actor"] != block.source.actor_uri:
raise ValueError("Undo actor does not match its Block object", data)
# Delete the follow
block.delete()