class APObjectTag(db.Model):
id = db.Column(db.Integer, primary_key=True)
type = db.Column(db.Enum(APObjectType))
href = db.Column(db.String(256))
name = db.Column(db.String(64))
ap_object_id = db.Column(db.ForeignKey('ap_object.id'), nullable=False)
ap_object = db.relationship('APObject',
foreign_keys=[ap_object_id],
backref=db.backref(
'tags', cascade='all, delete-orphan'))
def __init__(self, ap_object_id, _type, href, name):
self.ap_object_id = ap_object_id
self.type = _type
self.href = href
self.name = name
def to_dict(self):
output = {'type': self.type.value}
if self.href is not None:
output['href'] = self.href
if self.name is not None:
output['name'] = self.name
return output
class Following(db.Model):
'''
Representation of who a user is following both locally
and federally.
This model also records which ActivityPub outbox page the
follower most recently requested to view for a given leader.
'''
id = db.Column(db.Integer, nullable=False, primary_key=True)
approved = db.Column(db.Boolean, nullable=False)
leader = db.Column(db.String(256), nullable=False)
followers_collection = db.Column(db.String(256), nullable=False)
follower_id = db.Column(db.Integer,
db.ForeignKey('actor.id'),
nullable=False)
follower = db.relationship('Actor', backref='following')
def __init__(self,
follower_id,
leader,
followers_collection,
approved=False):
self.follower_id = follower_id
self.leader = leader
self.followers_collection = followers_collection
self.approved = approved
class Notification(db.Model):
id = db.Column(db.Integer, primary_key=True)
actor_id = db.Column(db.Integer, db.ForeignKey('ap_object.id'))
content = db.Column(db.String(256), nullable=False)
date = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)
type = db.Column(db.String(16), nullable=False)
actor = db.relationship('Actor')
def __init__(self, actor, content, _type):
'''
actor: Actor to which this notification belongs
content (str): Message contents of the notification
_type (str): Type of notification (ie, Follow, Dislike, Mention, etc.)
'''
self.actor_id = actor.id
self.content = content
self.type = _type
def to_dict(self):
return {
'id': self.id,
'content': self.content,
'published': xsd_datetime(self.date),
'type': self.type
}
class User(db.Model):
id = db.Column(db.Integer, nullable=False, primary_key=True)
username = db.Column(db.String(255), nullable=False)
password_hash = db.Column(db.String(255), nullable=False)
actors = db.relationship('Actor')
def __init__(self, username, password):
self.username = username.lower()
self.password_hash = hashpw(bytes(password, 'utf-8'), gensalt())
class User(db.Model):
id = db.Column(db.Integer, nullable=False, primary_key=True)
username = db.Column(db.String(32), unique=True, nullable=False)
password_hash = db.Column(db.String(255), nullable=False)
primary_actor_id = db.Column(db.Integer, db.ForeignKey('actor.id'))
primary_actor = db.relationship('Actor', foreign_keys=[primary_actor_id])
def __init__(self, username, password):
self.username = username.lower()
self.password_hash = hashpw(bytes(password, 'utf-8'), gensalt())
class APObjectRecipient(db.Model):
id = db.Column(db.Integer, primary_key=True)
ap_object_id = db.Column(db.Integer,
db.ForeignKey('ap_object.id'),
nullable=False)
method = db.Column(db.String(3), nullable=False)
recipient = db.Column(db.String(256), nullable=False)
ap_object = db.relationship('APObject', backref='recipients')
def __init__(self, ap_object_id, method, recipient):
self.ap_object_id = ap_object_id
self.method = method
self.recipient = recipient
class APObjectRecipient(db.Model):
id = db.Column(db.Integer, primary_key=True)
ap_object_id = db.Column(db.Integer,
db.ForeignKey('ap_object.id'),
nullable=False)
method = db.Column(db.String(3), nullable=False)
recipient = db.Column(db.String(256), nullable=False)
ap_object = db.relationship(
'APObject',
foreign_keys=[ap_object_id],
backref=db.backref('recipients', cascade='all, delete-orphan'))
def __init__(self, method, recipient):
self.method = method
self.recipient = recipient
class Note(db.Model):
id = db.Column(db.Integer, nullable=False, primary_key=True)
actor_id = db.Column(db.Integer, db.ForeignKey('actor.id'), nullable=False)
content = db.Column(db.String(1024), nullable=False)
author = db.relationship('Actor')
published = db.Column(db.DateTime, default=datetime.utcnow)
def to_dict(self):
return {}
class Actor(db.Model):
id = db.Column(db.Integer, primary_key=True)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
public_key = db.Column(db.Text(16639)) #PEM format
private_key = db.Column(db.Text(16639)) #PEM format
username = db.Column(db.String(32), nullable=False)
user = db.relationship('User')
notes = db.relationship('Note')
def __init__(self, *args, **kwargs):
if kwargs.get('user_id') != None:
self.user_id = kwargs.get('user_id')
elif kwargs.get('user') != None:
self.user_id = user.id
else:
raise Exception(
'Instantiating an Actor requires either a user object or user id. '
)
if kwargs.get('username') != None:
self.username = kwargs.get('username')
def to_dict(self):
api_url = config['api_url']
username = self.username
return {
'@context': [
'https://www.w3.org/ns/activitystreams',
'https://w3id.org/security/v1'
],
'id':
f'{api_url}/actors/{username}',
'type':
'Person',
'inbox':
f'{api_url}/actors/{username}/inbox',
'outbox':
f'{api_url}/actors/{username}/outbox',
'followers':
f'{api_url}/actors/{username}/followers',
'following':
f'{api_url}/actors/{username}/following',
'liked':
f'{api_url}/actors/{username}/liked',
'preferredUsername':
self.username,
'publicKey': {
'actor': f'{api_url}/actors/{username}',
'id': f'{api_url}/actors/{username}#main-key',
'publicKeyPem': self.public_key
}
}
class APObjectAttributedTo(db.Model):
id = db.Column(db.Integer, primary_key=True)
internal_actor_id = db.Column(db.ForeignKey('actor.id'))
external_actor_id = db.Column(db.String(1024))
ap_object_id = db.Column(db.Integer,
db.ForeignKey('ap_object.id'),
nullable=False)
ap_object = db.relationship('APObject',
uselist=False,
foreign_keys=[ap_object_id])
internal_actor = db.relationship('Actor', foreign_keys=[internal_actor_id])
class FollowedBy(db.Model):
'''
Representation of who is following a local Vagabond actor. The inboxes
(and shared inboxes, if they exist) of the followers are stored in this table
as well.
'''
id = db.Column(db.Integer, primary_key=True)
leader_id = db.Column(db.Integer,
db.ForeignKey('ap_object.id'),
nullable=False)
leader = db.relationship('Actor', backref='followed_by')
approved = db.Column(db.Boolean, nullable=False)
follower = db.Column(db.String(256), nullable=False) #URL of follower
follower_inbox = db.Column(db.String(256), nullable=False)
follower_shared_inbox = db.Column(db.String(256), nullable=True)
def __init__(self,
leader_id,
follower,
follower_inbox,
follower_shared_inbox=None,
approved=True):
'''
leader_id: int
follower: str
URL of the follower
follower_inbox: str
?follower_shared_inbox: str
'''
self.leader_id = leader_id
self.follower = follower
self.follower_inbox = follower_inbox
self.follower_shared_inbox = follower_shared_inbox
self.approved = approved
class APObjectAttributedTo(db.Model):
id = db.Column(db.Integer, primary_key=True)
internal_actor_id = db.Column(db.ForeignKey('ap_object.id'))
external_actor_id = db.Column(db.String(1024))
ap_object_id = db.Column(db.Integer,
db.ForeignKey('ap_object.id'),
nullable=False)
ap_object = db.relationship('APObject',
foreign_keys=[ap_object_id],
backref=db.backref(
'attributions',
cascade='all, delete-orphan'))
class Actor(APObject):
id = db.Column(db.Integer, db.ForeignKey('ap_object.id'), primary_key=True)
username = db.Column(db.String(32), unique=True, nullable=False)
public_key = db.Column(db.Text(16639))
private_key = db.Column(db.Text(16639))
user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
user = db.relationship('User', backref='actors', foreign_keys=[user_id])
__mapper_args__ = {'polymorphic_identity': APObjectType.PERSON}
def __init__(self, username, user=None, user_id=None):
self.username = username
if user_id is not None:
self.user_id = user_id
elif user is not None:
self.user_id = user.id
else:
raise Exception(
'Instantiating an Actor requires either a user object or user id. '
)
key = RSA.generate(2048)
self.private_key = key.export_key()
self.public_key = key.publickey().export_key()
self.type = APObjectType.PERSON
def to_dict(self):
api_url = config['api_url']
username = self.username
output = super().to_dict()
output['id'] = f'{api_url}/actors/{username}'
output['inbox'] = f'{api_url}/actors/{username}/inbox'
output['outbox'] = f'{api_url}/actors/{username}/outbox'
output['followers'] = f'{api_url}/actors/{username}/followers'
output['following'] = f'{api_url}/actors/{username}/following'
output['liked'] = f'{api_url}/actors/{username}/liked'
output['preferredUsername'] = self.username
output['endpoints'] = {'sharedInbox': f'{api_url}/inbox'}
output['publicKey'] = {
'actor': f'{api_url}/actors/{username}',
'id': f'{api_url}/actors/{username}#main-key',
'publicKeyPem': self.public_key
}
return output
class Actor(APObject):
username = db.Column(db.String(32), unique=True)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
user = db.relationship('User', backref='actors', foreign_keys=[user_id])
__mapper_args__ = {'polymorphic_identity': APObjectType.PERSON}
def __init__(self, username, user=None, user_id=None):
self.username = username
if user_id is not None:
self.user_id = user_id
elif user is not None:
self.user_id = user.id
else:
raise Exception(
'Instantiating an Actor requires either a user object or user id. '
)
self.type = APObjectType.PERSON
def to_dict(self):
api_url = os.environ['API_URL']
username = self.username
output = super().to_dict()
output['id'] = f'{api_url}/actors/{username}'
output['inbox'] = f'{api_url}/actors/{username}/inbox'
output['outbox'] = f'{api_url}/actors/{username}/outbox'
output['followers'] = f'{api_url}/actors/{username}/followers'
output['following'] = f'{api_url}/actors/{username}/following'
output['liked'] = f'{api_url}/actors/{username}/liked'
output['preferredUsername'] = self.username
output['endpoints'] = {'sharedInbox': f'{api_url}/inbox'}
output['publicKey'] = {
'actor': f'{api_url}/actors/{username}',
'id': f'{api_url}/actors/{username}#main-key',
'publicKeyPem': os.environ['PUBLIC_KEY']
}
return output
class APObject(db.Model):
'''
Superclass for all ActivityPub objects including instances of Activity
'''
id = db.Column(db.Integer, primary_key=True)
external_id = db.Column(db.String(256), unique=True)
in_reply_to_internal_id = db.Column(db.ForeignKey('ap_object.id'))
in_reply_to_external_id = db.Column(db.String(256))
content = db.Column(db.String(4096))
published = db.Column(db.DateTime, default=datetime.utcnow)
type = db.Column(db.Enum(APObjectType))
#attributedTo property
internal_author_id = db.Column(db.Integer, db.ForeignKey('ap_object.id'))
external_author_id = db.Column(db.String(256))
__mapper_args__ = {
'polymorphic_identity': APObjectType.OBJECT,
'polymorphic_on': type
}
@staticmethod
def get_object_from_url(url):
'''
Takes the provided URL and attempts to locate an object with the matching external_id.
This method works even for locally stored objects without an external_id property by parsing
the provided URL and extracting the ID.
'''
api_url = os.environ['API_URL']
if url.replace(api_url, '') != url:
url = url.replace(api_url, '')
splits = url.split('/')
if len(splits) == 3:
if splits[1] == 'actors':
try:
username = splits[2]
return db.session.query(vagabond.models.Actor).filter(
db.func.lower(username) == db.func.lower(
vagabond.models.Actor.username)).first()
except:
return None
elif splits[1] == 'objects':
try:
_id = int(splits[2])
return db.session.query(
vagabond.models.APObject).get(_id)
except:
return None
else:
obj = db.session.query(APObject).filter(
APObject.external_id == url).first()
return obj
def set_in_reply_to(self, in_reply_to):
'''
Sets the inReplyTo propety of this APObject
'''
if isinstance(in_reply_to, dict):
if 'id' in in_reply_to:
self.in_reply_to_external_id = in_reply_to['id']
obj = APObject.get_object_from_url(in_reply_to['id'])
if obj is not None:
self.in_reply_to_internal_id = obj.id
else:
raise Exception(
'Cannot set inReplyTo property: provided dictionary lacks \'id\' property.'
)
elif isinstance(in_reply_to, str):
self.in_reply_to_external_id = in_reply_to
obj = APObject.get_object_from_url(in_reply_to)
if obj is not None:
self.in_reply_to_internal_id = obj.id
elif (isinstance(in_reply_to, db.Model)):
self.in_reply_to_external_id = in_reply_to.to_dict()['id']
self.in_reply_to_internal_id = in_reply_to.id
def to_dict(self):
api_url = os.environ['API_URL']
output = {
'@context': ["https://www.w3.org/ns/activitystreams"],
'type': self.type.value,
}
if self.external_id is not None:
output['id'] = self.external_id
else:
output['id'] = f'{api_url}/objects/{self.id}'
#inReplyTo - what this object is in reply to
if self.in_reply_to_internal_id is not None:
in_reply_to = db.session.query(APObject).get(
self.in_reply_to_internal_id)
if in_reply_to is not None:
output['inReplyTo'] = in_reply_to.to_dict()
elif self.in_reply_to_external_id is not None:
output['inReplyTo'] = self.in_reply_to_external_id
#inReplyTo - what objects are a reply to this one
if self.type == APObjectType.NOTE and self.id is not None:
total_items = db.session.query(APObject).filter(
APObject.in_reply_to_internal_id == self.id).count()
if total_items > 0:
output['replies'] = f'{api_url}/objects/{self.id}/replies'
#attributedTo
if hasattr(
self,
'external_author_id') and self.external_author_id is not None:
output['attributedTo'] = self.external_author_id
elif hasattr(
self,
'internal_author_id') and self.internal_author_id is not None:
attributed_to = db.session.query(APObject).get(
self.internal_author_id)
if attributed_to is not None:
output['attributedTo'] = attributed_to.to_dict()['id']
#tag property
if len(self.tags) > 0:
output['tag'] = []
for tag in self.tags:
output['tag'].append(tag.to_dict())
if hasattr(self, 'content') and self.content is not None:
output['content'] = self.content
if hasattr(self, 'published'):
output['published'] = xsd_datetime(self.published)
if hasattr(self, 'recipients'):
for recipient in self.recipients:
if recipient.method not in output:
output[recipient.method] = []
output[recipient.method].append(recipient.recipient)
return output
def add_tag(self, tag):
'''
def __init__(self, ap_object_id, type, href, name):
Adds a tag to this object.
tag: dict | APObjectTag
'''
if isinstance(tag, dict):
_type = None
if tag['type'] == 'Mention':
self.tags.append(
APObjectTag(self.id, APObjectType.MENTION, tag.get('href'),
tag.get('name')))
else:
raise Exception('Only supported tag type is Mention')
elif isinstance(tag, APObjectTag):
self.tags.append(tag)
else:
raise Exception(
'APObject#add_tag method only accepts dictionaries and instances of APObjectTag as input. Some other type was provided.'
)
def add_recipient(self, method, recipient):
'''
method = 'to' | 'bto' | 'cc' | 'bcc'
recipient = Actor URL ID
Adds an actor as a recipient of this object using either the to, bto, cc, or bcc
ActivityPub fields.
'''
method = method.lower()
if method != 'to' and method != 'bto' and method != 'cc' and method != 'bcc':
raise Exception(
"Only acceptable values for APObject#add_recipient are 'to', 'bto', 'cc', and 'bcc'"
)
self.recipients.append(APObjectRecipient(method, recipient))
def add_all_recipients(self, obj: dict):
'''
Takes a dictionary object which contains some combination of
the 'to', 'bto', 'cc', and 'bcc' fields and adds the intended recipients
as recipients of this object.
The four aformentioned fields can be either strings or lists.
'''
keys = ['to', 'bto', 'cc', 'bcc']
for key in keys:
recipients = obj.get(key)
if recipients is not None:
if isinstance(recipients, str):
recipients = [recipients]
elif isinstance(recipients, list) is not True:
raise Exception(
f'APObject#add_all_recipients method given an object whose {key} value was neither a string nor an array.'
)
#prevent duplicate entries
uniques = []
for recipient in recipients:
if recipients not in uniques:
uniques.append(recipient)
for recipient in uniques:
self.add_recipient(key, recipient)
def attribute_to(self, author):
'''
author: str | Model | int
A string indicates that the object is being attributed to an external actor while
a SQLAlchemy model or integer indicates a local actor.
'''
#TODO: use get_object_from_url to set internal author id
if isinstance(author, str):
self.external_author_id = author
elif isinstance(author, db.Model):
self.internal_author_id = author.id
elif isinstance(author, int):
self.internal_author_id = author
class Activity(APObject):
internal_object_id = db.Column(db.ForeignKey('ap_object.id'))
external_object_id = db.Column(db.String(1024))
internal_actor_id = db.Column(db.ForeignKey('ap_object.id'))
external_actor_id = db.Column(db.String(1024))
internal_object = db.relationship('APObject', foreign_keys=[internal_object_id], remote_side=APObject.id, backref=db.backref('activities', cascade='all, delete-orphan'))
__mapper_args__ = {
'polymorphic_identity': APObjectType.ACTIVITY
}
def set_object(self, obj):
'''
Input: vagabond.models.APObject | str | dict
Takes an instance of APObject, a URL representing the object,
or a dictionary representing the object and wraps this instance
of Activity around it.
'''
if isinstance(obj, db.Model):
self.internal_object_id = obj.id
elif isinstance(obj, str):
interal_object = APObject.get_object_from_url(obj)
if interal_object is not None:
self.internal_object_id = interal_object.id
self.external_object_id = obj
elif isinstance(obj, dict) and 'id' in obj:
interal_object = APObject.get_object_from_url(obj['id'])
if interal_object is not None:
self.internal_object_id = interal_object.id
self.external_object_id = obj['id']
else:
raise Exception('Activity#set_object method requires an APObject, a string, or a dictionary')
def set_actor(self, actor):
'''
Input: vagabond.models.Actor | str | dict
'''
if isinstance(actor, db.Model):
self.internal_actor_id = actor.id
elif isinstance(actor, str):
self.external_actor_id = actor
elif isinstance(actor, dict) and 'id' in actor:
self.external_actor_id = actor['id']
else:
raise Exception('Activity#set_actor method requires an Actor, a string, or a dictionary')
def to_dict(self):
output = super().to_dict()
if self.internal_object_id is not None:
_object = db.session.query(APObject).get(self.internal_object_id)
if _object is not None:
output['object'] = _object.to_dict()
elif self.external_object_id is not None:
output['object'] = self.external_object_id
else:
raise Exception('Activites must have an internal or external object.')
if self.internal_actor_id is not None:
output['actor'] = db.session.query(APObject).get(self.internal_actor_id).to_dict()['id']
elif self.external_actor_id is not None:
output['actor'] = self.external_actor_id
else:
raise Exception('Activies must have an internal or external actor')
return output
class Activity(APObject):
id = db.Column(db.Integer, db.ForeignKey('ap_object.id'), primary_key=True)
internal_object_id = db.Column(db.ForeignKey('ap_object.id'))
external_object_id = db.Column(db.String(1024))
internal_actor_id = db.Column(db.ForeignKey('actor.id'))
external_actor_id = db.Column(db.String(1024))
actor = db.relationship('Actor',
foreign_keys=[internal_actor_id
]) #Person performing the activity
object = db.relationship('APObject',
foreign_keys=internal_object_id,
uselist=False)
__mapper_args__ = {
'polymorphic_identity': APObjectType.ACTIVITY,
'inherit_condition': id == APObject.id
}
def set_object(self, obj):
'''
Input: vagabond.models.APObject | str | dict
Takes an instance of APObject, a URL representing the object,
or a dictionary representing the object and wraps this instance
of Activity around it.
'''
if isinstance(obj, db.Model):
self.internal_object_id = obj.id
elif isinstance(obj, str):
self.external_object_id = obj
elif isinstance(obj, dict) and 'id' in obj:
self.external_object_id = obj['id']
else:
raise Exception(
'Activity#set_object method requires an APObject, a string, or a dictionary'
)
def set_actor(self, actor):
'''
Input: vagabond.models.Actor | str | dict
'''
if isinstance(actor, db.Model):
self.internal_actor_id = actor.id
elif isinstance(actor, str):
self.external_actor_id = actor
elif isinstance(actor, dict) and 'id' in actor:
self.external_actor_id = actor['id']
else:
raise Exception(
'Activity#set_actor method requires an Actor, a string, or a dictionary'
)
def to_dict(self):
output = super().to_dict()
if self.object is not None:
output['object'] = self.object.to_dict()
elif self.external_object_id is not None:
output['object'] = self.external_object_id
else:
raise Exception(
'Activites must have an internal or external object.')
if self.internal_actor_id is not None:
output[
'actor'] = f'{config["api_url"]}/actors/{self.actor.username}'
elif self.external_actor_id is not None:
output['actor'] = self.external_actor_id
else:
raise Exception('Activies must have an internal or external actor')
return output
class APObject(db.Model):
'''
Superclass for all ActivityPub objects including instances of Activity
'''
id = db.Column(db.Integer, primary_key=True)
external_id = db.Column(db.String(256), unique=True)
context = ["https://www.w3.org/ns/activitystreams"]
content = db.Column(db.String(4096))
published = db.Column(db.DateTime, default=datetime.utcnow)
type = db.Column(db.Enum(APObjectType))
attributed_to = db.relationship('APObjectAttributedTo', uselist=False)
__mapper_args__ = {
'polymorphic_identity': APObjectType.OBJECT,
'polymorphic_on': type
}
def to_dict(self):
api_url = config['api_url']
output = {
'@context': self.context,
'type': self.type.value,
}
if self.external_id is not None:
output['id'] = self.external_id
else:
output['id'] = f'{api_url}/objects/{self.id}'
if self.attributed_to is not None:
if self.attributed_to.internal_actor_id is not None:
output[
'attributedTo'] = f'{api_url}/actors/{self.attributed_to.internal_actor.username}'
elif self.attributed_to.external_actor_id is not None:
output['attributedTo'] = self.attributed_to.external_actor_id
if self.content is not None:
output['content'] = self.content
if self.published is not None:
output['published'] = xsd_datetime(self.published)
if hasattr(self, 'recipients'):
for recipient in self.recipients:
if output.get(recipient.method) is None:
output[recipient.method] = [recipient.recipient]
else:
output[recipient.method].append(recipient.recipient)
return output
def add_recipient(self, method: str, recipient):
'''
method = 'to' | 'bto' | 'cc' | 'bcc'
recipient = Actor URL ID
Adds an actor as a recipient of this object using either the to, bto, cc, or bcc
ActivityPub fields. This method adds records to the database but does not commit or flush
them.
'''
method = method.lower()
if method != 'to' and method != 'bto' and method != 'cc' and method != 'bcc':
raise Exception(
"Only acceptable values for APObject#add_recipient are 'to', 'bto', 'cc', and 'bcc'"
)
db.session.add((APObjectRecipient(self.id, method, recipient)))
def add_all_recipients(self, obj: dict):
'''
Takes a dictionary object which contains some combination of
the 'to', 'bto', 'cc', and 'bcc' fields and adds the intended recipients
as recipients of this object.
The four aformentioned fields can be either strings or lists.
'''
keys = ['to', 'bto', 'cc', 'bcc']
for key in keys:
value = obj.get(key)
if value is not None:
if isinstance(value, str):
value = [value]
elif isinstance(value, list) is not True:
raise Exception(
f'APObject#add_all_recipients method given an object whose {key} value was neither a string nor an array.'
)
for _value in value:
self.add_recipient(key, _value)
def add_to_inbox(self, actor):
'''
actor: Vagabond.models.Actor | int
Puts this object into the inbox of a local actor.
'''
def attribute_to(self, author):
'''
author: str | Model | int
Creates an instance of APObjectAttributedTo that represents an attribution
to the input id, external actor URL, or vagabond.models.Actor instance.
A string indicates that the object is being attributed to an external actor while
a SQLAlchemy model or integer indicates a local actor.
The newly created instance of APObjectAttributedTo is added to the database session,
but not committed or flushed.
'''
attribution = APObjectAttributedTo()
attribution.ap_object_id = self.id
if isinstance(author, str):
attribution.external_actor_id = author
elif isinstance(author, db.Model):
attribution.internal_actor_id = author.id
elif isinstance(author, int):
attribution.internal_actor_id = author
db.session.add(attribution)