bridgy-fed/salmon.py

84 wiersze
2.6 KiB
Python

"""Handles requests for Salmon endpoints: actors, inbox, etc.
https://github.com/salmon-protocol/salmon-protocol/blob/master/draft-panzer-salmon-00.html
https://github.com/salmon-protocol/salmon-protocol/blob/master/draft-panzer-magicsig-01.html
"""
import logging
import re
from xml.etree.ElementTree import ParseError
from django_salmon import magicsigs, utils
from flask import request
from granary import atom
from oauth_dropins.webutil import util
from oauth_dropins.webutil.flask_util import error
from app import app
import common
logger = logging.getLogger(__name__)
# from django_salmon.feeds
ATOM_NS = 'http://www.w3.org/2005/Atom'
ATOM_THREADING_NS = 'http://purl.org/syndication/thread/1.0'
SUPPORTED_VERBS = (
'checkin',
'create',
'favorite',
'like',
'share',
'tag',
'update',
)
@app.post(f'/<regex("{common.ACCT_RE}|{common.DOMAIN_RE}"):acct>/salmon')
def slap(acct):
"""Accepts POSTs to /[ACCT]/salmon and converts to outbound webmentions."""
# TODO: unify with activitypub
body = request.get_data(as_text=True)
logger.info(f'Got: {body}')
try:
parsed = utils.parse_magic_envelope(body)
except ParseError as e:
error('Could not parse POST body as XML', exc_info=True)
data = parsed['data']
logger.info(f'Decoded: {data}')
# check that we support this activity type
try:
activity = atom.atom_to_activity(data)
except ParseError as e:
error('Could not parse envelope data as XML', exc_info=True)
verb = activity.get('verb')
if verb and verb not in SUPPORTED_VERBS:
error(f'Sorry, {verb} activities are not supported yet.', status=501)
# verify author and signature
author = util.get_url(activity.get('actor'))
if ':' not in author:
author = f'acct:{author}'
elif not author.startswith('acct:'):
error(f'Author URI {author} has unsupported scheme; expected acct:')
logger.info(f'Fetching Salmon key for {author}')
if not magicsigs.verify(data, parsed['sig'], author_uri=author):
error('Could not verify magic signature.')
logger.info('Verified magic signature.')
# Verify that the timestamp is recent. Required by spec.
# I get that this helps prevent spam, but in practice it's a bit silly,
# and other major implementations don't (e.g. Mastodon), so forget it.
#
# updated = utils.parse_updated_from_atom(data)
# if not utils.verify_timestamp(updated):
# error('Timestamp is more than 1h old.')
# send webmentions to each target
activity = atom.atom_to_activity(data)
common.send_webmentions(activity, protocol='ostatus', source_atom=data)
return ''