forked from mirrors/bookwyrm
302 lines
10 KiB
Python
302 lines
10 KiB
Python
''' base model with default fields '''
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from base64 import b64encode
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from functools import reduce
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import operator
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from uuid import uuid4
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from Crypto.PublicKey import RSA
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from Crypto.Signature import pkcs1_15
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from Crypto.Hash import SHA256
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from django.core.paginator import Paginator
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from django.db import models
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from django.db.models import Q
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from django.dispatch import receiver
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from bookwyrm import activitypub
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from bookwyrm.settings import DOMAIN, PAGE_LENGTH
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from .fields import ImageField, ManyToManyField, RemoteIdField
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class BookWyrmModel(models.Model):
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''' shared fields '''
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created_date = models.DateTimeField(auto_now_add=True)
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updated_date = models.DateTimeField(auto_now=True)
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remote_id = RemoteIdField(null=True, activitypub_field='id')
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def get_remote_id(self):
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''' generate a url that resolves to the local object '''
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base_path = 'https://%s' % DOMAIN
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if hasattr(self, 'user'):
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base_path = self.user.remote_id
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model_name = type(self).__name__.lower()
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return '%s/%s/%d' % (base_path, model_name, self.id)
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class Meta:
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''' this is just here to provide default fields for other models '''
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abstract = True
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@property
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def local_path(self):
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''' how to link to this object in the local app '''
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return self.get_remote_id().replace('https://%s' % DOMAIN, '')
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@receiver(models.signals.post_save)
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#pylint: disable=unused-argument
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def execute_after_save(sender, instance, created, *args, **kwargs):
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''' set the remote_id after save (when the id is available) '''
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if not created or not hasattr(instance, 'get_remote_id'):
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return
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if not instance.remote_id:
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instance.remote_id = instance.get_remote_id()
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instance.save()
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def unfurl_related_field(related_field, sort_field=None):
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''' load reverse lookups (like public key owner or Status attachment '''
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if hasattr(related_field, 'all'):
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return [unfurl_related_field(i) for i in related_field.order_by(
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sort_field).all()]
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if related_field.reverse_unfurl:
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return related_field.field_to_activity()
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return related_field.remote_id
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class ActivitypubMixin:
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''' add this mixin for models that are AP serializable '''
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activity_serializer = lambda: {}
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reverse_unfurl = False
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def __init__(self, *args, **kwargs):
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''' collect some info on model fields '''
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self.image_fields = []
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self.many_to_many_fields = []
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self.simple_fields = [] # "simple"
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for field in self._meta.get_fields():
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if not hasattr(field, 'field_to_activity'):
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continue
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if isinstance(field, ImageField):
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self.image_fields.append(field)
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elif isinstance(field, ManyToManyField):
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self.many_to_many_fields.append(field)
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else:
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self.simple_fields.append(field)
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self.activity_fields = self.image_fields + \
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self.many_to_many_fields + self.simple_fields
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self.deserialize_reverse_fields = self.deserialize_reverse_fields \
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if hasattr(self, 'deserialize_reverse_fields') else []
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self.serialize_reverse_fields = self.serialize_reverse_fields \
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if hasattr(self, 'serialize_reverse_fields') else []
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super().__init__(*args, **kwargs)
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@classmethod
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def find_existing_by_remote_id(cls, remote_id):
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''' look up a remote id in the db '''
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return cls.find_existing({'id': remote_id})
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@classmethod
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def find_existing(cls, data):
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''' compare data to fields that can be used for deduplation.
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This always includes remote_id, but can also be unique identifiers
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like an isbn for an edition '''
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filters = []
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for field in cls._meta.get_fields():
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if not hasattr(field, 'deduplication_field') or \
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not field.deduplication_field:
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continue
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value = data.get(field.get_activitypub_field())
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if not value:
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continue
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filters.append({field.name: value})
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if hasattr(cls, 'origin_id') and 'id' in data:
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# kinda janky, but this handles special case for books
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filters.append({'origin_id': data['id']})
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if not filters:
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# if there are no deduplication fields, it will match the first
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# item no matter what. this shouldn't happen but just in case.
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return None
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objects = cls.objects
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if hasattr(objects, 'select_subclasses'):
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objects = objects.select_subclasses()
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# an OR operation on all the match fields
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match = objects.filter(
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reduce(
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operator.or_, (Q(**f) for f in filters)
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)
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)
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# there OUGHT to be only one match
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return match.first()
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def to_activity(self):
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''' convert from a model to an activity '''
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activity = generate_activity(self)
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return self.activity_serializer(**activity).serialize()
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def to_create_activity(self, user, **kwargs):
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''' returns the object wrapped in a Create activity '''
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activity_object = self.to_activity(**kwargs)
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signature = None
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create_id = self.remote_id + '/activity'
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if 'content' in activity_object:
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signer = pkcs1_15.new(RSA.import_key(user.key_pair.private_key))
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content = activity_object['content']
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signed_message = signer.sign(SHA256.new(content.encode('utf8')))
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signature = activitypub.Signature(
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creator='%s#main-key' % user.remote_id,
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created=activity_object['published'],
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signatureValue=b64encode(signed_message).decode('utf8')
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)
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return activitypub.Create(
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id=create_id,
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actor=user.remote_id,
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to=activity_object['to'],
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cc=activity_object['cc'],
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object=activity_object,
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signature=signature,
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).serialize()
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def to_delete_activity(self, user):
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''' notice of deletion '''
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return activitypub.Delete(
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id=self.remote_id + '/activity',
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actor=user.remote_id,
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to=['%s/followers' % user.remote_id],
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cc=['https://www.w3.org/ns/activitystreams#Public'],
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object=self.to_activity(),
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).serialize()
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def to_update_activity(self, user):
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''' wrapper for Updates to an activity '''
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activity_id = '%s#update/%s' % (self.remote_id, uuid4())
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return activitypub.Update(
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id=activity_id,
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actor=user.remote_id,
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to=['https://www.w3.org/ns/activitystreams#Public'],
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object=self.to_activity()
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).serialize()
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def to_undo_activity(self, user):
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''' undo an action '''
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return activitypub.Undo(
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id='%s#undo' % self.remote_id,
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actor=user.remote_id,
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object=self.to_activity()
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).serialize()
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class OrderedCollectionPageMixin(ActivitypubMixin):
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''' just the paginator utilities, so you don't HAVE to
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override ActivitypubMixin's to_activity (ie, for outbox '''
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@property
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def collection_remote_id(self):
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''' this can be overriden if there's a special remote id, ie outbox '''
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return self.remote_id
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def to_ordered_collection(self, queryset, \
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remote_id=None, page=False, collection_only=False, **kwargs):
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''' an ordered collection of whatevers '''
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if not queryset.ordered:
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raise RuntimeError('queryset must be ordered')
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remote_id = remote_id or self.remote_id
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if page:
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return to_ordered_collection_page(
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queryset, remote_id, **kwargs)
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if collection_only or not hasattr(self, 'activity_serializer'):
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serializer = activitypub.OrderedCollection
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activity = {}
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else:
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serializer = self.activity_serializer
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# a dict from the model fields
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activity = generate_activity(self)
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if remote_id:
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activity['id'] = remote_id
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paginated = Paginator(queryset, PAGE_LENGTH)
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# add computed fields specific to orderd collections
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activity['totalItems'] = paginated.count
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activity['first'] = '%s?page=1' % remote_id
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activity['last'] = '%s?page=%d' % (remote_id, paginated.num_pages)
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return serializer(**activity).serialize()
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# pylint: disable=unused-argument
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def to_ordered_collection_page(
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queryset, remote_id, id_only=False, page=1, **kwargs):
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''' serialize and pagiante a queryset '''
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paginated = Paginator(queryset, PAGE_LENGTH)
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activity_page = paginated.page(page)
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if id_only:
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items = [s.remote_id for s in activity_page.object_list]
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else:
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items = [s.to_activity() for s in activity_page.object_list]
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prev_page = next_page = None
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if activity_page.has_next():
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next_page = '%s?page=%d' % (remote_id, activity_page.next_page_number())
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if activity_page.has_previous():
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prev_page = '%s?page=%d' % \
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(remote_id, activity_page.previous_page_number())
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return activitypub.OrderedCollectionPage(
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id='%s?page=%s' % (remote_id, page),
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partOf=remote_id,
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orderedItems=items,
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next=next_page,
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prev=prev_page
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).serialize()
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class OrderedCollectionMixin(OrderedCollectionPageMixin):
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''' extends activitypub models to work as ordered collections '''
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@property
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def collection_queryset(self):
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''' usually an ordered collection model aggregates a different model '''
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raise NotImplementedError('Model must define collection_queryset')
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activity_serializer = activitypub.OrderedCollection
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def to_activity(self, **kwargs):
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''' an ordered collection of the specified model queryset '''
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return self.to_ordered_collection(self.collection_queryset, **kwargs)
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def generate_activity(obj):
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''' go through the fields on an object '''
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activity = {}
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for field in obj.activity_fields:
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field.set_activity_from_field(activity, obj)
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if hasattr(obj, 'serialize_reverse_fields'):
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# for example, editions of a work
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for model_field_name, activity_field_name, sort_field in \
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obj.serialize_reverse_fields:
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related_field = getattr(obj, model_field_name)
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activity[activity_field_name] = \
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unfurl_related_field(related_field, sort_field)
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if not activity.get('id'):
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activity['id'] = obj.get_remote_id()
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return activity
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