moviewyrm/bookwyrm/models/base_model.py
Mouse Reeve d92fb53333 Handle absent remote ids
it oughtent get to this state, but...
2020-12-03 17:23:08 -08:00

217 lines
7.4 KiB
Python

''' base model with default fields '''
from base64 import b64encode
from uuid import uuid4
from Crypto.PublicKey import RSA
from Crypto.Signature import pkcs1_15
from Crypto.Hash import SHA256
from django.core.paginator import Paginator
from django.db import models
from django.dispatch import receiver
from bookwyrm import activitypub
from bookwyrm.settings import DOMAIN, PAGE_LENGTH
from .fields import RemoteIdField
PrivacyLevels = models.TextChoices('Privacy', [
'public',
'unlisted',
'followers',
'direct'
])
class BookWyrmModel(models.Model):
''' shared fields '''
created_date = models.DateTimeField(auto_now_add=True)
updated_date = models.DateTimeField(auto_now=True)
remote_id = RemoteIdField(null=True, activitypub_field='id')
def get_remote_id(self):
''' generate a url that resolves to the local object '''
base_path = 'https://%s' % DOMAIN
if hasattr(self, 'user'):
base_path = self.user.remote_id
model_name = type(self).__name__.lower()
return '%s/%s/%d' % (base_path, model_name, self.id)
class Meta:
''' this is just here to provide default fields for other models '''
abstract = True
@receiver(models.signals.post_save)
def execute_after_save(sender, instance, created, *args, **kwargs):
''' set the remote_id after save (when the id is available) '''
if not created or not hasattr(instance, 'get_remote_id'):
return
if not instance.remote_id:
instance.remote_id = instance.get_remote_id()
instance.save()
def unfurl_related_field(related_field):
''' 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.all()]
if related_field.reverse_unfurl:
return related_field.field_to_activity()
return related_field.remote_id
class ActivitypubMixin:
''' add this mixin for models that are AP serializable '''
activity_serializer = lambda: {}
reverse_unfurl = False
def to_activity(self):
''' convert from a model to an activity '''
activity = {}
for field in self._meta.get_fields():
if not hasattr(field, 'field_to_activity'):
continue
value = field.field_to_activity(getattr(self, field.name))
if value is None:
continue
key = field.get_activitypub_field()
if key in activity and isinstance(activity[key], list):
# handles tags on status, which accumulate across fields
activity[key] += value
else:
activity[key] = value
if hasattr(self, 'serialize_reverse_fields'):
# for example, editions of a work
for field_name in self.serialize_reverse_fields:
related_field = getattr(self, field_name)
activity[field_name] = unfurl_related_field(related_field)
if not activity.get('id'):
activity['id'] = self.get_remote_id()
return self.activity_serializer(**activity).serialize()
def to_create_activity(self, user):
''' returns the object wrapped in a Create activity '''
activity_object = self.to_activity()
signer = pkcs1_15.new(RSA.import_key(user.private_key))
content = activity_object['content']
signed_message = signer.sign(SHA256.new(content.encode('utf8')))
create_id = self.remote_id + '/activity'
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' % (user.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' % user.remote_id,
actor=user.remote_id,
object=self.to_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, **kwargs):
''' an ordered collection of whatevers '''
remote_id = remote_id or self.remote_id
if page:
return to_ordered_collection_page(
queryset, remote_id, **kwargs)
name = self.name if hasattr(self, 'name') else None
owner = self.user.remote_id if hasattr(self, 'user') else ''
paginated = Paginator(queryset, PAGE_LENGTH)
return activitypub.OrderedCollection(
id=remote_id,
totalItems=paginated.count,
name=name,
owner=owner,
first='%s?page=1' % remote_id,
last='%s?page=%d' % (remote_id, paginated.num_pages)
).serialize()
def to_ordered_collection_page(queryset, remote_id, id_only=False, page=1):
''' 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)