sedi-relay/relay/processors.py

import asyncio
import logging

from cachetools import LRUCache
from uuid import uuid4

from .database import RELAY_SOFTWARE
from .misc import Message


cache = LRUCache(1024)


def person_check(actor, software):
	## pleroma and akkoma use Person for the actor type for some reason
	if software in {'akkoma', 'pleroma'} and actor.id != f'https://{actor.domain}/relay':
		return True

	## make sure the actor is an application
	elif actor.type != 'Application':
		return True


async def handle_relay(request, s):
	if request.message.objectid in cache:
		logging.verbose(f'already relayed {request.message.objectid}')
		return

	if request.message.get('to') != ['https://www.w3.org/ns/activitystreams#Public']:
		logging.verbose('Message was not public')
		logging.verbose(request.message.get('to'))
		return

	message = Message.new_announce(
		host = request.config.host,
		object = request.message.objectid
	)

	cache[request.message.objectid] = message.id
	logging.debug(f'>> relay: {message}')

	inboxes = s.distill_inboxes(request.message)

	for inbox in inboxes:
		request.app.push_message(inbox, message)


async def handle_forward(request, s):
	if request.message.id in cache:
		logging.verbose(f'already forwarded {request.message.id}')
		return

	message = Message.new_announce(
		host = request.config.host,
		object = request.message
	)

	cache[request.message.id] = message.id
	logging.debug(f'>> forward: {message}')

	inboxes = s.distill_inboxes(request.message)

	for inbox in inboxes:
		request.app.push_message(inbox, message)


async def handle_follow(request, s):
	approve = True

	nodeinfo = await request.app.client.fetch_nodeinfo(request.actor.domain)
	software = nodeinfo.sw_name if nodeinfo else None

	## reject if the actor isn't whitelisted while the whiltelist is enabled
	if s.get_config('whitelist') and not s.get_whitelist(request.actor.domain):
		logging.verbose(f'Rejected actor for not being in the whitelist: {request.actor.id}')
		approve = False

	## reject if software used by actor is banned
	if s.get_ban('software', software):
		logging.verbose(f'Rejected follow from actor for using specific software: actor={request.actor.id}, software={software}')
		approve = False

	## reject if the actor is not an instance actor
	if person_check(request.actor, software):
		logging.verbose(f'Non-application actor tried to follow: {request.actor.id}')
		approve = False

	if approve:
		if not request.instance:
			s.put_instance(
				domain = request.actor.domain,
				actor = request.actor.id,
				inbox = request.actor.shared_inbox,
				actor_data = request.actor,
				software = software,
				followid = request.message.id,
				accept = not s.get_config('require_approval')
			)

			if s.get_config('require_approval'):
				return

		else:
			s.put_instance(
				domain = request.actor.domain,
				followid = request.message.id
			)

	# Rejects don't seem to work right with mastodon
	request.app.push_message(
		request.actor.inbox,
		Message.new_response(
			host = request.config.host,
			actor = request.message.actorid,
			followid = request.message.id,
			accept = approve
		)
	)

	## Don't send a follow if the the follow has been rejected
	if not approve:
		return

	## Make sure two relays aren't continuously following each other
	if software in RELAY_SOFTWARE and not request.instance:
		return

	# Are Akkoma and Pleroma the only two that expect a follow back?
	# Ignoring only Mastodon for now
	if software != 'mastodon':
		request.app.push_message(
			request.actor.shared_inbox,
			Message.new_follow(
				host = request.config.host,
				actor = request.actor.id
			)
		)


async def handle_undo(request, s):
	## If the object is not a Follow, forward it
	if request.message.object.type != 'Follow':
		return await handle_forward(request)

	instance_follow = request.instance.followid
	message_follow = request.message.object.id

	if person_check(request.actor, request.instance.software):
		return logging.verbose(f'Non-application actor tried to unfollow: {request.actor.id}')

	if instance_follow and instance_follow != message_follow:
		return logging.verbose(f'Followid does not match: {instance_follow}, {message_follow}')

	s.delete('instances', id=request.instance.id)
	logging.verbose(f'Removed inbox: {request.instance.inbox}')

	if request.instance.software != 'mastodon':
		request.app.push_message(
			request.actor.shared_inbox,
			Message.new_unfollow(
				host = request.config.host,
				actor = request.actor.id,
				follow = request.message
			)
		)


processors = {
	'Announce': handle_relay,
	'Create': handle_relay,
	'Delete': handle_forward,
	'Follow': handle_follow,
	'Undo': handle_undo,
	'Update': handle_forward,
}


async def run_processor(request):
	if request.message.type not in processors:
		return

	with request.database.session as s:
		if request.instance:
			new_data = {}

			if not request.instance.software:
				logging.verbose(f'Fetching nodeinfo for instance: {request.instance.domain}')
				nodeinfo = await request.app.client.fetch_nodeinfo(request.instance.domain)

				if nodeinfo:
					new_data['software'] = nodeinfo.sw_name

			if not request.instance.actor:
				logging.verbose(f'Fetching actor for instance: {request.instance.domain}')
				new_data['actor'] = request.signature.keyid.split('#', 1)[0]

			if not request.instance.actor_data:
				new_data['actor_data'] = request.actor

			if new_data:
				s.put_instance(request.actor.domain, **new_data)

		logging.verbose(f'New "{request.message.type}" from actor: {request.actor.id}')
		return await processors[request.message.type](request, s)