moviewyrm/bookwyrm/views/inbox.py
2021-02-15 16:27:25 -08:00

80 lines
2.8 KiB
Python

''' incoming activities '''
import json
from urllib.parse import urldefrag
from django.http import HttpResponse
from django.http import HttpResponseBadRequest, HttpResponseNotFound
from django.shortcuts import get_object_or_404
from django.views import View
import requests
from bookwyrm import activitypub, models
from bookwyrm.signatures import Signature
# pylint: disable=no-self-use
class Inbox(View):
''' requests sent by outside servers'''
def post(self, request, username=None):
''' only works as POST request '''
# first let's do some basic checks to see if this is legible
if username:
try:
models.User.objects.get(localname=username)
except models.User.DoesNotExist:
return HttpResponseNotFound()
# is it valid json? does it at least vaguely resemble an activity?
try:
resp = request.body
activity_json = json.loads(resp)
activity_type = activity_json['type'] # Follow, Accept, Create, etc
except (json.decoder.JSONDecodeError, KeyError):
return HttpResponseBadRequest()
# verify the signature
if not has_valid_signature(request, activity_json):
if activity_json['type'] == 'Delete':
# Pretend that unauth'd deletes succeed. Auth may be failing
# because the resource or owner of the resource might have
# been deleted.
return HttpResponse()
return HttpResponse(status=401)
# get the activity dataclass from the type field
try:
serializer = getattr(activitypub, activity_type)
serializer(**activity_json)
except (AttributeError, activitypub.ActivitySerializerError):
return HttpResponseNotFound()
return HttpResponse()
def has_valid_signature(request, activity):
''' verify incoming signature '''
try:
signature = Signature.parse(request)
key_actor = urldefrag(signature.key_id).url
if key_actor != activity.get('actor'):
raise ValueError("Wrong actor created signature.")
remote_user = activitypub.resolve_remote_id(models.User, key_actor)
if not remote_user:
return False
try:
signature.verify(remote_user.key_pair.public_key, request)
except ValueError:
old_key = remote_user.key_pair.public_key
remote_user = activitypub.resolve_remote_id(
models.User, remote_user.remote_id, refresh=True
)
if remote_user.key_pair.public_key == old_key:
raise # Key unchanged.
signature.verify(remote_user.key_pair.public_key, request)
except (ValueError, requests.exceptions.HTTPError):
return False
return True