federated purge of user content

app/user/routes.py

@@ -14,6 +14,7 @@ from app.models import Post, Community, CommunityMember, User, PostReply, PostVo
     Instance, Report, UserBlock, CommunityBan, CommunityJoinRequest, CommunityBlock, Filter
 from app.user import bp
 from app.user.forms import ProfileForm, SettingsForm, DeleteAccountForm, ReportUserForm, FilterEditForm
+from app.user.utils import purge_user_then_delete
 from app.utils import get_setting, render_template, markdown_to_html, user_access, markdown_to_text, shorten_string, \
     is_image_url, ensure_directory_exists, gibberish, file_get_contents, community_membership, user_filters_home, \
     user_filters_posts, user_filters_replies, moderating_communities, joined_communities
@@ -449,14 +450,19 @@ def ban_purge_profile(actor):
             flash(_('You cannot purge yourself.'), 'error')
         else:
             user.banned = True
-            user.deleted = True
+            # user.deleted = True # DO NOT set user.deleted until the deletion of their posts has been federated
-            db.session.commit()
-
-            user.purge_content()
             db.session.commit()
 
             # todo: empty relevant caches
-            # todo: federate deletion
+
+            # federate deletion
+            if user.is_local():
+                purge_user_then_delete(user.id)
+            else:
+                user.deleted = True
+                user.delete_dependencies()
+                user.purge_content()
+                db.session.commit()
 
             flash(f'{actor} has been banned, deleted and all their content deleted.')
     else:

app/user/utils.py

@@ -0,0 +1,117 @@
+from time import sleep
+
+from flask import current_app, json
+
+from app import celery, db
+from app.activitypub.signature import post_request
+from app.activitypub.util import default_context
+from app.community.util import send_to_remote_instance
+from app.models import User, CommunityMember, Community, Instance, Site, utcnow, ActivityPubLog
+from app.utils import gibberish, ap_datetime, instance_banned
+
+
+def purge_user_then_delete(user_id):
+    if current_app.debug:
+        purge_user_then_delete_task(user_id)
+    else:
+        purge_user_then_delete_task.delay(user_id)
+
+
+@celery.task
+def purge_user_then_delete_task(user_id):
+    user = User.query.get(user_id)
+    if user:
+        # posts
+        for post in user.posts:
+            if not post.community.local_only:
+                delete_json = {
+                    'id': f"https://{current_app.config['SERVER_NAME']}/activities/delete/{gibberish(15)}",
+                    'type': 'Delete',
+                    'actor': user.profile_id(),
+                    'audience': post.community.profile_id(),
+                    'to': [post.community.profile_id(), 'https://www.w3.org/ns/activitystreams#Public'],
+                    'published': ap_datetime(utcnow()),
+                    'cc': [
+                        user.followers_url()
+                    ],
+                    'object': post.ap_id,
+                }
+
+                if not post.community.is_local():  # this is a remote community, send it to the instance that hosts it
+                    success = post_request(post.community.ap_inbox_url, delete_json, user.private_key,
+                                           user.ap_profile_id + '#main-key')
+
+                else:  # local community - send it to followers on remote instances, using Announce
+                    announce = {
+                        "id": f"https://{current_app.config['SERVER_NAME']}/activities/announce/{gibberish(15)}",
+                        "type": 'Announce',
+                        "to": [
+                            "https://www.w3.org/ns/activitystreams#Public"
+                        ],
+                        "actor": post.community.ap_profile_id,
+                        "cc": [
+                            post.community.ap_followers_url
+                        ],
+                        '@context': default_context(),
+                        'object': delete_json
+                    }
+
+                    for instance in post.community.following_instances():
+                        if instance.inbox and not instance_banned(instance.domain):
+                            send_to_remote_instance(instance.id, post.community.id, announce)
+
+        # unsubscribe
+        communities = CommunityMember.query.filter_by(user_id=user_id).all()
+        for membership in communities:
+            community = Community.query.get(membership.community_id)
+            unsubscribe_from_community(community, user)
+
+        # federate deletion of account
+        if user.is_local():
+            instances = Instance.query.all()
+            site = Site.query.get(1)
+            payload = {
+                "@context": default_context(),
+                "actor": user.ap_profile_id,
+                "id": f"{user.ap_profile_id}#delete",
+                "object": user.ap_profile_id,
+                "to": [
+                    "https://www.w3.org/ns/activitystreams#Public"
+                ],
+                "type": "Delete"
+            }
+            for instance in instances:
+                if instance.inbox and instance.id != 1:
+                    post_request(instance.inbox, payload, site.private_key,
+                                 f"https://{current_app.config['SERVER_NAME']}#main-key")
+
+        sleep(100)                                  # wait a while for any related activitypub traffic to die down.
+        user.deleted = True
+        user.delete_dependencies()
+        user.purge_content()
+        db.session.commit()
+
+
+def unsubscribe_from_community(community, user):
+    undo_id = f"https://{current_app.config['SERVER_NAME']}/activities/undo/" + gibberish(15)
+    follow = {
+        "actor": f"https://{current_app.config['SERVER_NAME']}/u/{user.user_name}",
+        "to": [community.ap_profile_id],
+        "object": community.ap_profile_id,
+        "type": "Follow",
+        "id": f"https://{current_app.config['SERVER_NAME']}/activities/follow/{gibberish(15)}"
+    }
+    undo = {
+        'actor': user.profile_id(),
+        'to': [community.ap_profile_id],
+        'type': 'Undo',
+        'id': undo_id,
+        'object': follow
+    }
+    activity = ActivityPubLog(direction='out', activity_id=undo_id, activity_type='Undo',
+                              activity_json=json.dumps(undo), result='processing')
+    db.session.add(activity)
+    db.session.commit()
+    post_request(community.ap_inbox_url, undo, user.private_key, user.profile_id() + '#main-key')
+    activity.result = 'success'
+    db.session.commit()