moviewyrm/bookwyrm/views/inbox.py
2021-03-08 08:49:10 -08:00

100 lines
3.3 KiB
Python

""" incoming activities """
import json
from urllib.parse import urldefrag
from django.http import HttpResponse
from django.http import HttpResponseBadRequest, HttpResponseNotFound
from django.utils.decorators import method_decorator
from django.views import View
from django.views.decorators.csrf import csrf_exempt
import requests
from bookwyrm import activitypub, models
from bookwyrm.tasks import app
from bookwyrm.signatures import Signature
@method_decorator(csrf_exempt, name="dispatch")
# pylint: disable=no-self-use
class Inbox(View):
""" requests sent by outside servers"""
def post(self, request, username=None):
""" only works as POST request """
# make sure the user's inbox even exists
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:
activity_json = json.loads(request.body)
except json.decoder.JSONDecodeError:
return HttpResponseBadRequest()
if (
not "object" in activity_json
or not "type" in activity_json
or not activity_json["type"] in activitypub.activity_objects
):
return HttpResponseNotFound()
# 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)
activity_task.delay(activity_json)
return HttpResponse()
@app.task
def activity_task(activity_json):
""" do something with this json we think is legit """
# lets see if the activitypub module can make sense of this json
try:
activity = activitypub.parse(activity_json)
except activitypub.ActivitySerializerError:
return
# cool that worked, now we should do the action described by the type
# (create, update, delete, etc)
try:
activity.action()
except activitypub.ActivitySerializerError:
# this is raised if the activity is discarded
return
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(key_actor, model=models.User)
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(
remote_user.remote_id, model=models.User, 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