"""Convert between ActivityStreams 1 and 2, including ActivityPub.
AS2: http://www.w3.org/TR/activitystreams-core/
https://www.w3.org/TR/activitypub/
https://activitypub.rocks/
AS1: http://activitystrea.ms/specs/json/1.0/
http://activitystrea.ms/specs/json/schema/activity-schema.html
"""
import copy
import datetime
import logging
from oauth_dropins.webutil import util
from . import as1
logger = logging.getLogger(__name__)
# ActivityPub Content-Type details:
# https://www.w3.org/TR/activitypub/#retrieving-objects
CONTENT_TYPE = 'application/activity+json'
CONTENT_TYPE_LD = 'application/ld+json;profile="https://www.w3.org/ns/activitystreams"'
CONNEG_HEADERS = {
'Accept': f'{CONTENT_TYPE}; q=0.9, {CONTENT_TYPE_LD}; q=0.8',
}
CONTEXT = 'https://www.w3.org/ns/activitystreams'
PUBLIC_AUDIENCE = 'https://www.w3.org/ns/activitystreams#Public'
# All known Public values, cargo culted from:
# https://socialhub.activitypub.rocks/t/visibility-to-cc-mapping/284
# https://docs.joinmastodon.org/spec/activitypub/#properties-used
PUBLICS = frozenset((
PUBLIC_AUDIENCE,
'as:Public',
'Public',
))
def _invert(d):
return {v: k for k, v in d.items()}
OBJECT_TYPE_TO_TYPE = {
'article': 'Article',
'audio': 'Audio',
'collection': 'Collection',
'comment': 'Note',
'event': 'Event',
# not in AS2 spec; needed for correct round trip conversion
'hashtag': 'Tag',
'image': 'Image',
# not in AS1 spec; needed to identify mentions in eg Bridgy Fed
'mention': 'Mention',
'note': 'Note',
'organization': 'Organization',
'person': 'Person',
'place': 'Place',
'question': 'Question',
'video': 'Video',
}
TYPE_TO_OBJECT_TYPE = _invert(OBJECT_TYPE_TO_TYPE)
TYPE_TO_OBJECT_TYPE['Note'] = 'note' # disambiguate
VERB_TO_TYPE = {
'accept': 'Accept',
'delete': 'Delete',
'favorite': 'Like',
'follow': 'Follow',
'invite': 'Invite',
'like': 'Like',
'post': 'Create',
'rsvp-maybe': 'TentativeAccept',
'reject': 'Reject',
'rsvp-no': 'Reject',
'rsvp-yes': 'Accept',
'share': 'Announce',
'tag': 'Add',
# not in AS1 spec; undo isn't a real AS1 verb
# https://activitystrea.ms/specs/json/schema/activity-schema.html#verbs
'undo': 'Undo',
'update': 'Update',
}
TYPE_TO_VERB = _invert(VERB_TO_TYPE)
# disambiguate
TYPE_TO_VERB.update({
'Accept': 'accept',
'Like': 'like',
'Reject': 'reject',
})
[docs]def from_as1(obj, type=None, context=CONTEXT, top_level=True):
"""Converts an ActivityStreams 1 activity or object to ActivityStreams 2.
Args:
obj: dict, AS1 activity or object
type: string, default type if type inference can't determine a type.
context: string, included as @context
Returns: dict, AS2 activity or object
"""
if not obj:
return {}
elif isinstance(obj, str):
return obj
elif not isinstance(obj, dict):
raise ValueError(f'Expected dict, got {obj!r}')
obj = copy.deepcopy(obj)
actor = obj.get('actor')
verb = obj.pop('verb', None)
obj_type = obj.pop('objectType', None)
type = (OBJECT_TYPE_TO_TYPE.get(verb or obj_type) or
VERB_TO_TYPE.get(verb or obj_type) or
type)
if context:
obj['@context'] = context
def all_from_as1(field, type=None, top_level=False):
return [from_as1(elem, type=type, context=None, top_level=top_level)
for elem in util.pop_list(obj, field)]
inner_objs = all_from_as1('object', top_level=top_level)
if len(inner_objs) == 1:
inner_objs = inner_objs[0]
if verb == 'stop-following':
type = 'Undo'
inner_objs = {
'@context': context,
'type': 'Follow',
'actor': actor.get('id') if isinstance(actor, dict) else actor,
'object': inner_objs.get('id'),
}
replies = obj.get('replies', {})
# to/cc audience, all ids, special caste public/unlisted
to = sorted(as1.get_ids(obj, 'to'))
cc = sorted(as1.get_ids(obj, 'cc'))
to_aliases = [to.get('alias') for to in util.pop_list(obj, 'to')]
if '@public' in to_aliases and PUBLIC_AUDIENCE not in to:
to.append(PUBLIC_AUDIENCE)
elif '@unlisted' in to_aliases and PUBLIC_AUDIENCE not in cc:
cc.append(PUBLIC_AUDIENCE)
in_reply_to = util.trim_nulls(all_from_as1('inReplyTo'))
if len(in_reply_to) == 1:
in_reply_to = in_reply_to[0]
attachments = all_from_as1('attachments')
# Mastodon profile metadata fields
# https://docs.joinmastodon.org/spec/activitypub/#PropertyValue
# https://github.com/snarfed/bridgy-fed/issues/323
if obj_type == 'person' and top_level:
links = {}
for link in as1.get_objects(obj, 'url') + as1.get_objects(obj, 'urls'):
url = link.get('value') or link.get('id')
name = link.get('displayName')
if util.is_web(url):
links[url] = {
'type': 'PropertyValue',
'name': name or 'Link',
'value': util.pretty_link(url, attrs={'rel': 'me'}),
}
attachments.extend(links.values())
# urls
urls = as1.object_urls(obj)
if len(urls) == 1:
urls = urls[0]
obj.update({
'type': type,
'name': obj.pop('displayName', None),
'actor': from_as1(actor, context=None, top_level=False),
'attachment': attachments,
'attributedTo': all_from_as1('author', type='Person'),
'inReplyTo': in_reply_to,
'object': inner_objs,
'tag': all_from_as1('tags'),
'preferredUsername': obj.pop('username', None),
'url': urls,
'urls': None,
'replies': from_as1(replies, context=None),
'mediaType': obj.pop('mimeType', None),
'to': to,
'cc': cc,
})
# question (poll) responses
# HACK: infer single vs multiple choice from whether
# votersCount matches the sum of votes for each option. not ideal!
voters = obj.get('votersCount')
votes = sum(opt.get('replies', {}).get('totalItems', 0)
for opt in util.get_list(obj, 'options'))
vote_field = 'oneOf' if voters == votes else 'anyOf'
obj[vote_field] = all_from_as1('options')
# images; separate featured (aka header) and non-featured.
images = util.get_list(obj, 'image')
featured = []
non_featured = []
if images:
for img in images:
# objectType featured is non-standard; granary uses it for u-featured
# microformats2 images
if isinstance(img, dict) and img.get('objectType') == 'featured':
featured.append(img)
else:
non_featured.append(img)
# prefer non-featured first for icon, featured for image. ActivityPub/Mastodon
# use icon for profile picture, image for header.
if obj_type == 'person':
obj['icon'] = from_as1((non_featured or featured)[0], type='Image',
context=None, top_level=False)
obj['image'] = [from_as1(img, type='Image', context=None)
for img in featured + non_featured]
if len(obj['image']) == 1:
obj['image'] = obj['image'][0]
# other type-specific fields
if obj_type == 'mention':
obj['href'] = util.get_first(obj, 'url')
obj.pop('url', None)
elif obj_type in ('audio', 'video'):
stream = util.pop_list(obj, 'stream')
if stream:
obj.update({
'url': stream[0].get('url'),
# file size in bytes. nonstandard, not in AS2 proper
'size': stream[0].get('size'),
})
duration = stream[0].get('duration')
if duration:
try:
# ISO 8601 duration
# https://www.w3.org/TR/activitystreams-vocabulary/#dfn-duration
# https://en.wikipedia.org/wiki/ISO_8601#Durations
obj['duration'] = util.to_iso8601_duration(
datetime.timedelta(seconds=duration))
except TypeError:
logger.warning(f'Dropping unexpected duration {duration!r}; expected int, is {duration.__class__}')
# location
loc = obj.get('location')
if loc:
obj['location'] = from_as1(loc, type='Place', context=None)
obj = util.trim_nulls(obj)
if list(obj.keys()) == ['url']:
return obj['url']
return obj
[docs]def to_as1(obj, use_type=True):
"""Converts an ActivityStreams 2 activity or object to ActivityStreams 1.
Args:
obj: dict, AS2 activity or object
use_type: boolean, whether to include objectType and verb
Returns: dict, AS1 activity or object
"""
def all_to_as1(field):
return [to_as1(elem) for elem in util.pop_list(obj, field)
if not (type == 'Person' and elem.get('type') == 'PropertyValue')]
if not obj:
return {}
elif isinstance(obj, str):
return obj
elif not isinstance(obj, dict):
raise ValueError(f'Expected dict, got {obj!r}')
obj = copy.deepcopy(obj)
obj.pop('@context', None)
# type to objectType + verb
type = obj.pop('type', None)
if use_type:
if type and not isinstance(type, str):
raise ValueError(f'Expected type to be string, got {type!r}')
obj['objectType'] = TYPE_TO_OBJECT_TYPE.get(type)
obj['verb'] = TYPE_TO_VERB.get(type)
inner_obj = as1.get_object(obj)
if obj.get('inReplyTo') and obj['objectType'] in ('note', 'article'):
obj['objectType'] = 'comment'
elif inner_obj.get('type') == 'Event':
if type == 'Accept':
obj['verb'] = 'rsvp-yes'
elif type == 'Reject':
obj['verb'] = 'rsvp-no'
if obj['verb'] and not obj['objectType']:
obj['objectType'] = 'activity'
# attachments: media, with mediaType image/... or video/..., override type. Eg
# Mastodon video attachments have type Document (!)
# https://docs.joinmastodon.org/spec/activitypub/#properties-used
media_type = obj.pop('mediaType', None)
if media_type:
media_type_prefix = media_type.split('/')[0]
if media_type_prefix in ('audio', 'image', 'video'):
type = media_type_prefix.capitalize()
obj.update({
'objectType': media_type_prefix,
'mimeType': media_type,
})
# attachments: Mastodon profile metadata fields, with type PropertyValue.
# https://docs.joinmastodon.org/spec/activitypub/#PropertyValue
#
# populate into corresponding URL in url/urls fields. have to do this one one
# level up, in the parent's object, because its data goes into the parent's
# url/urls fields
names = {}
for att in util.get_list(obj, 'attachment'):
name = att.get('name')
value = att.get('value')
if att.get('type') == 'PropertyValue' and value and name and name != 'Link':
a = util.parse_html(value).find('a')
if a and a.get('href'):
names[a['href']] = name
urls = [{'displayName': names[url], 'value': url} if url in names
else url
for url in util.get_list(obj, 'url')]
# ActivityPub/Mastodon uses icon for profile picture, image for header.
as1_images = []
image_urls = set()
icons = util.pop_list(obj, 'icon')
images = util.pop_list(obj, 'image')
# by convention, first element in AS2 images field is banner/header
if type == 'Person' and images:
images[0]['objectType'] = 'featured'
for as2_img in icons + images:
as1_img = to_as1(as2_img, use_type=False)
url = util.get_url(as1_img)
if url not in image_urls:
as1_images.append(as1_img)
image_urls.add(url)
# inner objects
inner_objs = all_to_as1('object')
actor = to_as1(as1.get_object(obj, 'actor'))
if type in ('Create', 'Update'):
for inner_obj in inner_objs:
if inner_obj.get('objectType') not in as1.ACTOR_TYPES:
inner_obj.setdefault('author', {}).update(actor)
if len(inner_objs) == 1:
inner_objs = inner_objs[0]
# special case Undo Follow
if type == 'Undo' and inner_objs.get('verb') == 'follow':
obj['verb'] = 'stop-following'
inner_inner_obj = as1.get_object(inner_objs)
inner_objs = {
'id': (inner_inner_obj.get('id') or util.get_url(inner_inner_obj, 'url')
if isinstance(inner_inner_obj, dict) else inner_inner_obj),
}
# audience, public or unlisted or neither
to = sorted(util.get_list(obj, 'to'))
cc = sorted(util.get_list(obj, 'cc'))
as1_to = [{'id': val} for val in to]
as1_cc = [{'id': val} for val in cc]
if PUBLICS.intersection(to):
as1_to.append({'objectType': 'group', 'alias': '@public'})
elif PUBLICS.intersection(cc):
as1_to.append({'objectType': 'group', 'alias': '@unlisted'})
obj.update({
'displayName': obj.pop('name', None),
'username': obj.pop('preferredUsername', None),
'actor': actor['id'] if actor.keys() == set(['id']) else actor,
'attachments': all_to_as1('attachment'),
'image': as1_images,
'inReplyTo': [to_as1(orig) for orig in util.get_list(obj, 'inReplyTo')],
'location': to_as1(obj.get('location')),
'object': inner_objs,
'tags': all_to_as1('tag'),
'to': as1_to,
'cc': as1_cc,
# question (poll) responses
'options': all_to_as1('anyOf') + all_to_as1('oneOf'),
'replies': to_as1(obj.get('replies')),
'url': urls[0] if urls else None,
'urls': urls if len(urls) > 1 else None,
})
# media
if type in ('Audio', 'Video'): # this may have been set above
duration = util.parse_iso8601_duration(obj.pop('duration', None))
if duration:
duration = duration.total_seconds()
obj['stream'] = {
'url': obj.pop('url', None),
# file size in bytes. nonstandard, not in AS1 proper
'size': obj.pop('size', None),
'duration': duration or None,
}
elif type == 'Mention':
obj['url'] = obj.pop('href', None)
# object author
attrib = util.pop_list(obj, 'attributedTo')
if attrib:
if len(attrib) > 1:
logger.warning(f'ActivityStreams 1 only supports single author; dropping extra attributedTo values: {attrib[1:]}')
attrib_as1 = to_as1(attrib[0])
obj.setdefault('author', {}).update(attrib_as1 if isinstance(attrib_as1, dict)
else {'id': attrib_as1})
return util.trim_nulls(obj)
[docs]def is_public(activity):
"""Returns True if the given AS2 object or activity is public or unlisted.
https://docs.joinmastodon.org/spec/activitypub/#properties-used
Args:
activity: dict, AS2 activity or object
"""
if not isinstance(activity, dict):
return False
audience = util.get_list(activity, 'to') + util.get_list(activity, 'cc')
obj = as1.get_object(activity)
audience.extend(util.get_list(obj, 'to') + util.get_list(obj, 'cc'))
return bool(PUBLICS.intersection(audience))