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Activitypub model code in more files

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Mouse Reeve 2021-02-04 12:36:39 -08:00
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bookwyrm/models/activitypub_mixin/__init__.py Normal file
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from . import *

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bookwyrm/models/activitypub_mixin/activitypub_mixin.py Normal file
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''' base model with default fields '''
from base64 import b64encode
from functools import reduce
import json
import operator
from uuid import uuid4
import requests
from Crypto.PublicKey import RSA
from Crypto.Signature import pkcs1_15
from Crypto.Hash import SHA256
from django.apps import apps
from django.db import models
from django.db.models import Q
from django.dispatch import receiver
from django.utils.http import http_date
from bookwyrm import activitypub
from bookwyrm.settings import USER_AGENT
from bookwyrm.signatures import make_signature, make_digest
from bookwyrm.tasks import app
from .fields import ImageField, ManyToManyField
class ActivitypubMixin:
''' add this mixin for models that are AP serializable '''
activity_serializer = lambda: {}
reverse_unfurl = False
def __init__(self, *args, **kwargs):
''' collect some info on model fields '''
self.image_fields = []
self.many_to_many_fields = []
self.simple_fields = [] # "simple"
for field in self._meta.get_fields():
if not hasattr(field, 'field_to_activity'):
continue
if isinstance(field, ImageField):
self.image_fields.append(field)
elif isinstance(field, ManyToManyField):
self.many_to_many_fields.append(field)
else:
self.simple_fields.append(field)
self.activity_fields = self.image_fields + \
self.many_to_many_fields + self.simple_fields
self.deserialize_reverse_fields = self.deserialize_reverse_fields \
if hasattr(self, 'deserialize_reverse_fields') else []
self.serialize_reverse_fields = self.serialize_reverse_fields \
if hasattr(self, 'serialize_reverse_fields') else []
super().__init__(*args, **kwargs)
def delete(self, *args, **kwargs):
''' broadcast suitable delete activities '''
@classmethod
def find_existing_by_remote_id(cls, remote_id):
''' look up a remote id in the db '''
return cls.find_existing({'id': remote_id})
@classmethod
def find_existing(cls, data):
''' compare data to fields that can be used for deduplation.
This always includes remote_id, but can also be unique identifiers
like an isbn for an edition '''
filters = []
for field in cls._meta.get_fields():
if not hasattr(field, 'deduplication_field') or \
not field.deduplication_field:
continue
value = data.get(field.get_activitypub_field())
if not value:
continue
filters.append({field.name: value})
if hasattr(cls, 'origin_id') and 'id' in data:
# kinda janky, but this handles special case for books
filters.append({'origin_id': data['id']})
if not filters:
# if there are no deduplication fields, it will match the first
# item no matter what. this shouldn't happen but just in case.
return None
objects = cls.objects
if hasattr(objects, 'select_subclasses'):
objects = objects.select_subclasses()
# an OR operation on all the match fields
match = objects.filter(
reduce(
operator.or_, (Q(**f) for f in filters)
)
)
# there OUGHT to be only one match
return match.first()
def broadcast(self, activity, sender, software=None):
''' send out an activity '''
broadcast_task.delay(
sender.id,
json.dumps(activity, cls=activitypub.ActivityEncoder),
self.get_recipients(software=software)
)
def get_recipients(self, software=None):
''' figure out which inbox urls to post to '''
# first we have to figure out who should receive this activity
privacy = self.privacy if hasattr(self, 'privacy') else 'public'
# is this activity owned by a user (statuses, lists, shelves), or is it
# general to the instance (like books)
user = self.user if hasattr(self, 'user') else None
if not user and self.__model__ == 'user':
# or maybe the thing itself is a user
user = self
# find anyone who's tagged in a status, for example
mentions = self.mention_users if hasattr(self, 'mention_users') else []
# we always send activities to explicitly mentioned users' inboxes
recipients = [u.inbox for u in mentions or []]
# unless it's a dm, all the followers should receive the activity
if privacy != 'direct':
user_model = apps.get_model('bookwyrm.User', require_ready=True)
# filter users first by whether they're using the desired software
# this lets us send book updates only to other bw servers
queryset = user_model.objects.filter(
bookwyrm_user=(software == 'bookwyrm')
)
# if there's a user, we only want to send to the user's followers
if user:
queryset = queryset.filter(following=user)
# ideally, we will send to shared inboxes for efficiency
shared_inboxes = queryset.filter(
shared_inbox__isnull=False
).values_list('shared_inbox', flat=True).distinct()
# but not everyone has a shared inbox
inboxes = queryset.filter(
shared_inboxes__isnull=True
).values_list('inbox', flat=True)
recipients += list(shared_inboxes) + list(inboxes)
return recipients
def to_activity(self):
''' convert from a model to an activity '''
activity = generate_activity(self)
return self.activity_serializer(**activity).serialize()
def to_create_activity(self, user, **kwargs):
''' returns the object wrapped in a Create activity '''
activity_object = self.to_activity(**kwargs)
signature = None
create_id = self.remote_id + '/activity'
if 'content' in activity_object:
signer = pkcs1_15.new(RSA.import_key(user.key_pair.private_key))
content = activity_object['content']
signed_message = signer.sign(SHA256.new(content.encode('utf8')))
signature = activitypub.Signature(
creator='%s#main-key' % user.remote_id,
created=activity_object['published'],
signatureValue=b64encode(signed_message).decode('utf8')
)
return activitypub.Create(
id=create_id,
actor=user.remote_id,
to=activity_object['to'],
cc=activity_object['cc'],
object=activity_object,
signature=signature,
).serialize()
def to_delete_activity(self, user):
''' notice of deletion '''
return activitypub.Delete(
id=self.remote_id + '/activity',
actor=user.remote_id,
to=['%s/followers' % user.remote_id],
cc=['https://www.w3.org/ns/activitystreams#Public'],
object=self.to_activity(),
).serialize()
def to_update_activity(self, user):
''' wrapper for Updates to an activity '''
activity_id = '%s#update/%s' % (self.remote_id, uuid4())
return activitypub.Update(
id=activity_id,
actor=user.remote_id,
to=['https://www.w3.org/ns/activitystreams#Public'],
object=self.to_activity()
).serialize()
def to_undo_activity(self, user):
''' undo an action '''
return activitypub.Undo(
id='%s#undo' % self.remote_id,
actor=user.remote_id,
object=self.to_activity()
).serialize()
def generate_activity(obj):
''' go through the fields on an object '''
activity = {}
for field in obj.activity_fields:
field.set_activity_from_field(activity, obj)
if hasattr(obj, 'serialize_reverse_fields'):
# for example, editions of a work
for model_field_name, activity_field_name, sort_field in \
obj.serialize_reverse_fields:
related_field = getattr(obj, model_field_name)
activity[activity_field_name] = \
unfurl_related_field(related_field, sort_field)
if not activity.get('id'):
activity['id'] = obj.get_remote_id()
return activity
def unfurl_related_field(related_field, sort_field=None):
''' load reverse lookups (like public key owner or Status attachment '''
if hasattr(related_field, 'all'):
return [unfurl_related_field(i) for i in related_field.order_by(
sort_field).all()]
if related_field.reverse_unfurl:
return related_field.field_to_activity()
return related_field.remote_id
@app.task
def broadcast_task(sender_id, activity, recipients):
''' the celery task for broadcast '''
user_model = apps.get_model('bookwyrm.User', require_ready=True)
sender = user_model.objects.get(id=sender_id)
errors = []
for recipient in recipients:
try:
sign_and_send(sender, activity, recipient)
except requests.exceptions.HTTPError as e:
errors.append({
'error': str(e),
'recipient': recipient,
'activity': activity,
})
return errors
def sign_and_send(sender, data, destination):
''' crpyto whatever and http junk '''
now = http_date()
if not sender.key_pair.private_key:
# this shouldn't happen. it would be bad if it happened.
raise ValueError('No private key found for sender')
digest = make_digest(data)
response = requests.post(
destination,
data=data,
headers={
'Date': now,
'Digest': digest,
'Signature': make_signature(sender, destination, now, digest),
'Content-Type': 'application/activity+json; charset=utf-8',
'User-Agent': USER_AGENT,
},
)
if not response.ok:
response.raise_for_status()
return response
@receiver(models.signals.post_save)
#pylint: disable=unused-argument
def execute_after_save(sender, instance, created, *args, **kwargs):
''' broadcast when a model instance is created or updated '''
# user content like statuses, lists, and shelves, have a "user" field
user = instance.user if hasattr(instance, 'user') else None
if user and not user.local:
# we don't want to broadcast when we save remote activities
return
if created:
if not user:
# book data and users don't need to broadcast on creation
return
# ordered collection items get "Add"ed
if hasattr(instance, 'to_add_activity'):
activity = instance.to_add_activity()
else:
# everything else gets "Create"d
activity = instance.to_create_activity(user)
else:
# now, handle updates
if not user:
# users don't have associated users, they ARE users
if sender.__class__ == 'User':
user = instance
# book data trakcs last editor
elif hasattr(instance, 'last_edited_by'):
user = instance.last_edited_by
# again, if we don't know the user or they're remote, don't bother
if not user or not user.local:
return
activity = instance.to_update_activity(user)
if activity and user and user.local:
instance.broadcast(activity, user)

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bookwyrm/models/activitypub_mixin/ordered_collection.py Normal file
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''' lists of objects '''
from django.core.paginator import Paginator
from bookwyrm import activitypub
from bookwyrm.settings import PAGE_LENGTH
from . import ActivitypubMixin, generate_activity
class OrderedCollectionPageMixin(ActivitypubMixin):
''' just the paginator utilities, so you don't HAVE to
override ActivitypubMixin's to_activity (ie, for outbox '''
@property
def collection_remote_id(self):
''' this can be overriden if there's a special remote id, ie outbox '''
return self.remote_id
def to_ordered_collection(self, queryset, \
remote_id=None, page=False, collection_only=False, **kwargs):
''' an ordered collection of whatevers '''
if not queryset.ordered:
raise RuntimeError('queryset must be ordered')
remote_id = remote_id or self.remote_id
if page:
return to_ordered_collection_page(
queryset, remote_id, **kwargs)
if collection_only or not hasattr(self, 'activity_serializer'):
serializer = activitypub.OrderedCollection
activity = {}
else:
serializer = self.activity_serializer
# a dict from the model fields
activity = generate_activity(self)
if remote_id:
activity['id'] = remote_id
paginated = Paginator(queryset, PAGE_LENGTH)
# add computed fields specific to orderd collections
activity['totalItems'] = paginated.count
activity['first'] = '%s?page=1' % remote_id
activity['last'] = '%s?page=%d' % (remote_id, paginated.num_pages)
return serializer(**activity).serialize()
# pylint: disable=unused-argument
def to_ordered_collection_page(
queryset, remote_id, id_only=False, page=1, **kwargs):
''' serialize and pagiante a queryset '''
paginated = Paginator(queryset, PAGE_LENGTH)
activity_page = paginated.page(page)
if id_only:
items = [s.remote_id for s in activity_page.object_list]
else:
items = [s.to_activity() for s in activity_page.object_list]
prev_page = next_page = None
if activity_page.has_next():
next_page = '%s?page=%d' % (remote_id, activity_page.next_page_number())
if activity_page.has_previous():
prev_page = '%s?page=%d' % \
(remote_id, activity_page.previous_page_number())
return activitypub.OrderedCollectionPage(
id='%s?page=%s' % (remote_id, page),
partOf=remote_id,
orderedItems=items,
next=next_page,
prev=prev_page
).serialize()
class OrderedCollectionMixin(OrderedCollectionPageMixin):
''' extends activitypub models to work as ordered collections '''
@property
def collection_queryset(self):
''' usually an ordered collection model aggregates a different model '''
raise NotImplementedError('Model must define collection_queryset')
activity_serializer = activitypub.OrderedCollection
def to_activity(self, **kwargs):
''' an ordered collection of the specified model queryset '''
return self.to_ordered_collection(self.collection_queryset, **kwargs)
class CollectionItemMixin(ActivitypubMixin):
''' for items that are part of an (Ordered)Collection '''
activity_serializer = activitypub.Add
object_field = collection_field = None
def to_add_activity(self):
''' AP for shelving a book'''
object_field = getattr(self, self.object_field)
collection_field = getattr(self, self.collection_field)
return activitypub.Add(
id='%s#add' % self.remote_id,
actor=self.user.remote_id,
object=object_field.to_activity(),
target=collection_field.remote_id
).serialize()
def to_remove_activity(self):
''' AP for un-shelving a book'''
object_field = getattr(self, self.object_field)
collection_field = getattr(self, self.collection_field)
return activitypub.Remove(
id='%s#remove' % self.remote_id,
actor=self.user.remote_id,
object=object_field.to_activity(),
target=collection_field.remote_id
).serialize()