kopia lustrzana https://github.com/snarfed/bridgy-fed
406 wiersze
14 KiB
Python
406 wiersze
14 KiB
Python
# coding=utf-8
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"""Misc common utilities.
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"""
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import itertools
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import logging
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import os
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import re
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import urllib.parse
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from flask import request
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from granary import as2
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from oauth_dropins.webutil import util, webmention
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from oauth_dropins.webutil.flask_util import error
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import requests
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from werkzeug.exceptions import BadGateway
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from models import Response
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logger = logging.getLogger(__name__)
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DOMAIN_RE = r'([^/:]+\.[^/:]+)'
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ACCT_RE = r'(?:acct:)?([^@]+)@' + DOMAIN_RE
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TLD_BLOCKLIST = ('7z', 'asp', 'aspx', 'gif', 'html', 'ico', 'jpg', 'jpeg', 'js',
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'json', 'php', 'png', 'rar', 'txt', 'yaml', 'yml', 'zip')
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HEADERS = {
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'User-Agent': 'Bridgy Fed (https://fed.brid.gy/)',
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}
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XML_UTF8 = "<?xml version='1.0' encoding='UTF-8'?>\n"
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LINK_HEADER_RE = re.compile(r""" *< *([^ >]+) *> *; *rel=['"]([^'"]+)['"] *""")
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AS2_PUBLIC_AUDIENCE = 'https://www.w3.org/ns/activitystreams#Public'
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# Content-Type values. All non-unicode strings because App Engine's wsgi.py
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# requires header values to be str, not unicode.
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#
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# ActivityPub Content-Type details:
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# https://www.w3.org/TR/activitypub/#retrieving-objects
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CONTENT_TYPE_AS2_LD = 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'
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CONTENT_TYPE_AS2 = 'application/activity+json'
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CONTENT_TYPE_AS1 = 'application/stream+json'
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CONTENT_TYPE_HTML = 'text/html; charset=utf-8'
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CONTENT_TYPE_ATOM = 'application/atom+xml'
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CONTENT_TYPE_MAGIC_ENVELOPE = 'application/magic-envelope+xml'
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CONNEG_HEADERS_AS2 = {
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'Accept': '%s; q=0.9, %s; q=0.8' % (CONTENT_TYPE_AS2, CONTENT_TYPE_AS2_LD),
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}
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CONNEG_HEADERS_AS2_HTML = {
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'Accept': CONNEG_HEADERS_AS2['Accept'] + ', %s; q=0.7' % CONTENT_TYPE_HTML,
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}
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SUPPORTED_VERBS = (
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'checkin',
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'create',
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'follow',
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'like',
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'post',
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'share',
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'tag',
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'update',
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)
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PRIMARY_DOMAIN = 'fed.brid.gy'
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OTHER_DOMAINS = (
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'bridgy-federated.appspot.com',
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'localhost',
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)
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DOMAINS = (PRIMARY_DOMAIN,) + OTHER_DOMAINS
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def requests_get(url, **kwargs):
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return _requests_fn(util.requests_get, url, **kwargs)
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def requests_post(url, **kwargs):
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return _requests_fn(util.requests_post, url, **kwargs)
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def _requests_fn(fn, url, parse_json=False, **kwargs):
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"""Wraps requests.* and adds raise_for_status() and User-Agent."""
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kwargs.setdefault('headers', {}).update(HEADERS)
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resp = fn(url, gateway=True, **kwargs)
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logger.info(f'Got {resp.status_code} headers: {resp.headers}')
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type = content_type(resp)
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if (type and type != 'text/html' and
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(type.startswith('text/') or type.endswith('+json') or type.endswith('/json'))):
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logger.info(resp.text)
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if parse_json:
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try:
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return resp.json()
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except ValueError:
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msg = "Couldn't parse response as JSON"
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logger.info(msg, exc_info=True)
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raise BadGateway(msg)
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return resp
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def get_as2(url):
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"""Tries to fetch the given URL as ActivityStreams 2.
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Uses HTTP content negotiation via the Content-Type header. If the url is
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HTML and it has a rel-alternate link with an AS2 content type, fetches and
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returns that URL.
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Args:
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url: string
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Returns:
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:class:`requests.Response`
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Raises:
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:class:`requests.HTTPError`, :class:`werkzeug.exceptions.HTTPException`
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If we raise a werkzeug HTTPException, it will have an additional
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requests_response attribute with the last requests.Response we received.
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"""
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def _error(resp):
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msg = "Couldn't fetch %s as ActivityStreams 2" % url
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logger.warning(msg)
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err = BadGateway(msg)
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err.requests_response = resp
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raise err
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resp = requests_get(url, headers=CONNEG_HEADERS_AS2_HTML)
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if content_type(resp) in (CONTENT_TYPE_AS2, CONTENT_TYPE_AS2_LD):
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return resp
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parsed = util.parse_html(resp)
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as2 = parsed.find('link', rel=('alternate', 'self'), type=(
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CONTENT_TYPE_AS2, CONTENT_TYPE_AS2_LD))
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if not (as2 and as2['href']):
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_error(resp)
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resp = requests_get(urllib.parse.urljoin(resp.url, as2['href']),
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headers=CONNEG_HEADERS_AS2)
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if content_type(resp) in (CONTENT_TYPE_AS2, CONTENT_TYPE_AS2_LD):
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return resp
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_error(resp)
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def content_type(resp):
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"""Returns a :class:`requests.Response`'s Content-Type, without charset suffix."""
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type = resp.headers.get('Content-Type')
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if type:
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return type.split(';')[0]
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def send_webmentions(activity_wrapped, proxy=None, **response_props):
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"""Sends webmentions for an incoming Salmon slap or ActivityPub inbox delivery.
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Args:
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activity_wrapped: dict, AS1 activity
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response_props: passed through to the newly created Responses
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"""
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activity = redirect_unwrap(activity_wrapped)
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verb = activity.get('verb')
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if verb and verb not in SUPPORTED_VERBS:
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error(f'{verb} activities are not supported yet.')
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# extract source and targets
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source = activity.get('url') or activity.get('id')
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obj = activity.get('object')
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obj_url = util.get_url(obj)
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targets = util.get_list(activity, 'inReplyTo')
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if isinstance(obj, dict):
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if not source or verb in ('create', 'post', 'update'):
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source = obj_url or obj.get('id')
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targets.extend(util.get_list(obj, 'inReplyTo'))
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tags = util.get_list(activity_wrapped, 'tags')
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obj_wrapped = activity_wrapped.get('object')
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if isinstance(obj_wrapped, dict):
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tags.extend(util.get_list(obj_wrapped, 'tags'))
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for tag in tags:
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if tag.get('objectType') == 'mention':
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url = tag.get('url')
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if url and url.startswith(request.host_url):
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targets.append(redirect_unwrap(url))
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if verb in ('follow', 'like', 'share'):
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targets.append(obj_url)
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targets = util.dedupe_urls(util.get_url(t) for t in targets)
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if not source:
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error("Couldn't find original post URL")
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if not targets:
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error("Couldn't find any target URLs in inReplyTo, object, or mention tags")
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# send webmentions and store Responses
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errors = [] # stores (code, body) tuples
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for target in targets:
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if util.domain_from_link(target) == util.domain_from_link(source):
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logger.info(f'Skipping same-domain webmention from {source} to {target}')
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continue
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response = Response(source=source, target=target, direction='in',
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**response_props)
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response.put()
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wm_source = (response.proxy_url()
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if verb in ('follow', 'like', 'share') or proxy
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else source)
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logger.info(f'Sending webmention from {wm_source} to {target}')
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try:
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endpoint = webmention.discover(target, headers=HEADERS).endpoint
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if endpoint:
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webmention.send(endpoint, wm_source, target, headers=HEADERS)
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response.status = 'complete'
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logger.info('Success!')
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else:
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response.status = 'ignored'
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logger.info('Ignoring.')
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except BaseException as e:
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errors.append(util.interpret_http_exception(e))
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response.put()
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if errors:
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msg = 'Errors: ' + ', '.join(f'{code} {body}' for code, body in errors)
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error(msg, status=int(errors[0][0] or 502))
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def postprocess_as2(activity, target=None, key=None):
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"""Prepare an AS2 object to be served or sent via ActivityPub.
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Args:
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activity: dict, AS2 object or activity
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target: dict, AS2 object, optional. The target of activity's inReplyTo or
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Like/Announce/etc object, if any.
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key: :class:`models.MagicKey`, optional. populated into publicKey field
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if provided.
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"""
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type = activity.get('type')
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# actor objects
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if type == 'Person':
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postprocess_as2_actor(activity)
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if not activity.get('publicKey'):
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# underspecified, inferred from this issue and Mastodon's implementation:
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# https://github.com/w3c/activitypub/issues/203#issuecomment-297553229
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# https://github.com/tootsuite/mastodon/blob/bc2c263504e584e154384ecc2d804aeb1afb1ba3/app/services/activitypub/process_account_service.rb#L77
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activity.update({
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'publicKey': {
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'id': activity.get('preferredUsername'),
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'publicKeyPem': key.public_pem().decode(),
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},
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'@context': (util.get_list(activity, '@context') +
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['https://w3id.org/security/v1']),
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})
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return activity
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for actor in (util.get_list(activity, 'attributedTo') +
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util.get_list(activity, 'actor')):
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postprocess_as2_actor(actor)
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# inReplyTo: singly valued, prefer id over url
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target_id = target.get('id') if target else None
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in_reply_to = activity.get('inReplyTo')
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if in_reply_to:
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if target_id:
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activity['inReplyTo'] = target_id
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elif isinstance(in_reply_to, list):
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if len(in_reply_to) > 1:
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logger.warning(
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"AS2 doesn't support multiple inReplyTo URLs! "
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'Only using the first: %s' % in_reply_to[0])
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activity['inReplyTo'] = in_reply_to[0]
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# Mastodon evidently requires a Mention tag for replies to generate a
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# notification to the original post's author. not required for likes,
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# reposts, etc. details:
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# https://github.com/snarfed/bridgy-fed/issues/34
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if target:
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for to in (util.get_list(target, 'attributedTo') +
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util.get_list(target, 'actor')):
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if isinstance(to, dict):
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to = to.get('url') or to.get('id')
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if to:
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activity.setdefault('tag', []).append({
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'type': 'Mention',
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'href': to,
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})
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# activity objects (for Like, Announce, etc): prefer id over url
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obj = activity.get('object')
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if obj:
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if isinstance(obj, dict) and not obj.get('id'):
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obj['id'] = target_id or obj.get('url')
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elif target_id and obj != target_id:
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activity['object'] = target_id
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# id is required for most things. default to url if it's not set.
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if not activity.get('id'):
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activity['id'] = activity.get('url')
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# TODO: find a better way to check this, sometimes or always?
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# removed for now since it fires on posts without u-id or u-url, eg
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# https://chrisbeckstrom.com/2018/12/27/32551/
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# assert activity.get('id') or (isinstance(obj, dict) and obj.get('id'))
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activity['id'] = redirect_wrap(activity.get('id'))
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activity['url'] = redirect_wrap(activity.get('url'))
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# copy image(s) into attachment(s). may be Mastodon-specific.
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# https://github.com/snarfed/bridgy-fed/issues/33#issuecomment-440965618
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obj_or_activity = obj if isinstance(obj, dict) else activity
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obj_or_activity.setdefault('attachment', []).extend(
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obj_or_activity.get('image', []))
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# cc public and target's author(s) and recipients
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# https://www.w3.org/TR/activitystreams-vocabulary/#audienceTargeting
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# https://w3c.github.io/activitypub/#delivery
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if type in as2.TYPE_TO_VERB or type in ('Article', 'Note'):
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recips = [AS2_PUBLIC_AUDIENCE]
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if target:
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recips += itertools.chain(*(util.get_list(target, field) for field in
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('actor', 'attributedTo', 'to', 'cc')))
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activity['cc'] = util.dedupe_urls(util.get_url(recip) or recip.get('id')
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for recip in recips)
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# wrap articles and notes in a Create activity
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if type in ('Article', 'Note'):
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activity = {
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'@context': as2.CONTEXT,
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'type': 'Create',
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'id': f'{activity["id"]}#bridgy-fed-create',
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'object': activity,
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}
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return util.trim_nulls(activity)
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def postprocess_as2_actor(actor):
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"""Prepare an AS2 actor object to be served or sent via ActivityPub.
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Args:
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actor: dict, AS2 actor object
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"""
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url = actor.get('url')
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if url:
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domain = urllib.parse.urlparse(url).netloc
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actor.update({
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'id': request.host_url + domain,
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'url': redirect_wrap(url),
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'preferredUsername': domain,
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})
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# required by pixelfed. https://github.com/snarfed/bridgy-fed/issues/39
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actor.setdefault('summary', '')
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def redirect_wrap(url):
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"""Returns a URL on our domain that redirects to this URL.
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...to satisfy Mastodon's non-standard domain matching requirement. :(
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Args:
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url: string
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https://github.com/snarfed/bridgy-fed/issues/16#issuecomment-424799599
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https://github.com/tootsuite/mastodon/pull/6219#issuecomment-429142747
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Returns: string, redirect url
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"""
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if not url:
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return url
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prefix = urllib.parse.urljoin(request.host_url, '/r/')
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if url.startswith(prefix):
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return url
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return prefix + url
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def redirect_unwrap(val):
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"""Removes our redirect wrapping from a URL, if it's there.
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url may be a string, dict, or list. dicts and lists are unwrapped
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recursively.
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Strings that aren't wrapped URLs are left unchanged.
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Args:
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url: string
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Returns: string, unwrapped url
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"""
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if isinstance(val, dict):
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return {k: redirect_unwrap(v) for k, v in val.items()}
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elif isinstance(val, list):
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return [redirect_unwrap(v) for v in val]
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elif isinstance(val, str):
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prefix = urllib.parse.urljoin(request.host_url, '/r/')
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if val.startswith(prefix):
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return util.follow_redirects(val[len(prefix):]).url
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elif val.startswith(request.host_url):
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domain = util.domain_from_link(urllib.parse.urlparse(val).path.strip('/'))
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return util.follow_redirects(domain).url
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return val
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