Retrieve remote post from Search (no pre-supplied community required)

app/activitypub/util.py

@@ -2430,3 +2430,106 @@ def resolve_remote_post(uri: str, community_id: int, announce_actor=None) -> Uni
                 return post
 
     return None
+
+
+def resolve_remote_post_from_search(uri: str) -> Union[Post, None]:
+    post = Post.query.filter_by(ap_id=uri).first()
+    if post:
+        return post
+
+    site = Site.query.get(1)
+
+    parsed_url = urlparse(uri)
+    uri_domain = parsed_url.netloc
+    actor_domain = None
+    actor = None
+    post_request = get_request(uri, headers={'Accept': 'application/activity+json'})
+    if post_request.status_code == 200:
+        post_data = post_request.json()
+        post_request.close()
+        # check again that it doesn't already exist (can happen with different but equivalent URLs)
+        post = Post.query.filter_by(ap_id=post_data['id']).first()
+        if post:
+            return post
+
+        # find the author of the post. Make sure their domain matches the site hosting it to migitage impersonation attempts
+        if 'attributedTo' in post_data:
+            if isinstance(post_data['attributedTo'], str):
+                actor = post_data['attributedTo']
+                parsed_url = urlparse(post_data['attributedTo'])
+                actor_domain = parsed_url.netloc
+            elif isinstance(post_data['attributedTo'], list):
+                for a in post_data['attributedTo']:
+                    if a['type'] == 'Person':
+                        actor = a['id']
+                        parsed_url = urlparse(a['id'])
+                        actor_domain = parsed_url.netloc
+                        break
+        if uri_domain != actor_domain:
+            return None
+
+        # find the community the post was submitted to
+        community = None
+        if not community and post_data['type'] == 'Page':                                         # lemmy
+            if 'audience' in post_data:
+                community_id = post_data['audience']
+                community = Community.query.filter_by(ap_profile_id=community_id).first()
+
+        if not community and post_data['type'] == 'Video':                                        # peertube
+            if 'attributedTo' in post_data and isinstance(post_data['attributedTo'], list):
+                for a in post_data['attributedTo']:
+                    if a['type'] == 'Group':
+                        community_id = a['id']
+                        community = Community.query.filter_by(ap_profile_id=community_id).first()
+                        if community:
+                            break
+
+        if not community:                                                                         # mastodon, etc
+            if 'inReplyTo' not in post_data or post_data['inReplyTo'] != None:
+                return None
+
+        if not community and 'to' in post_data and isinstance(post_data['to'], str):
+            community_id = post_data['to'].lower()
+            if not community_id == 'https://www.w3.org/ns/activitystreams#Public' and not community_id.endswith('/followers'):
+                community = Community.query.filter_by(ap_profile_id=community_id).first()
+        if not community and 'cc' in post_data and isinstance(post_data['cc'], str):
+            community_id = post_data['cc'].lower()
+            if not community_id == 'https://www.w3.org/ns/activitystreams#Public' and not community_id.endswith('/followers'):
+                community = Community.query.filter_by(ap_profile_id=community_id).first()
+        if not community and 'to' in post_data and isinstance(post_data['to'], list):
+            for t in post_data['to']:
+                community_id = t.lower()
+                if not community_id == 'https://www.w3.org/ns/activitystreams#Public' and not community_id.endswith('/followers'):
+                    community = Community.query.filter_by(ap_profile_id=community_id).first()
+                    if community:
+                        break
+        if not community and 'cc' in post_data and isinstance(post_data['to'], list):
+            for c in post_data['cc']:
+                community_id = c.lower()
+                if not community_id == 'https://www.w3.org/ns/activitystreams#Public' and not community_id.endswith('/followers'):
+                    community = Community.query.filter_by(ap_profile_id=community_id).first()
+                    if community:
+                        break
+
+        if not community:
+            return None
+
+        activity_log = ActivityPubLog(direction='in', activity_id=post_data['id'], activity_type='Resolve Post', result='failure')
+        if site.log_activitypub_json:
+            activity_log.activity_json = json.dumps(post_data)
+        db.session.add(activity_log)
+        user = find_actor_or_create(actor)
+        if user and community and post_data:
+            request_json = {
+              'id': f"https://{uri_domain}/activities/create/gibberish(15)",
+              'object': post_data
+            }
+            post = create_post(activity_log, community, request_json, user)
+            if post:
+                if 'published' in post_data:
+                    post.posted_at=post_data['published']
+                    post.last_active=post_data['published']
+                    db.session.commit()
+                return post
+
+    return None

app/search/routes.py

@@ -7,6 +7,8 @@ from app.models import Post, Language, Community
 from app.search import bp
 from app.utils import moderating_communities, joined_communities, render_template, blocked_domains, blocked_instances, \
     communities_banned_from, recently_upvoted_posts, recently_downvoted_posts, blocked_users
+from app.community.forms import RetrieveRemotePost
+from app.activitypub.util import resolve_remote_post_from_search
 
 
 @bp.route('/search', methods=['GET', 'POST'])
@@ -87,3 +89,20 @@ def run_search():
                                moderating_communities=moderating_communities(current_user.get_id()),
                                joined_communities=joined_communities(current_user.get_id()),
                                site=g.site)
+
+
+@bp.route('/retrieve_remote_post', methods=['GET', 'POST'])
+@login_required
+def retrieve_remote_post():
+    if current_user.banned:
+        return show_ban_message()
+    form = RetrieveRemotePost()
+    new_post = None
+    if form.validate_on_submit():
+        address = form.address.data.strip()
+        new_post = resolve_remote_post_from_search(address)
+        if new_post is None:
+            flash(_('Post not found.'), 'warning')
+
+    return render_template('community/retrieve_remote_post.html',
+                           title=_('Retrieve Remote Post'), form=form, new_post=new_post)

app/templates/community/retrieve_remote_post.html

@@ -11,7 +11,11 @@
                 <div class="card mt-5">
                     <div class="card-body p-6">
                         <div class="card-title">{{ _('Retrieve Remote Post') }}</div>
+                        {% if community %}
                             <p>Enter the full URL of the post submitted to {{ community.ap_id }}</p>
+                        {% else %}
+                            <p>Enter the full URL of the post</p>
+                        {% endif %}
                         <p>Note: URL needs to match the one from the post author's instance (which may be different than the community's instance)</p>
                         {{ render_form(form) }}
                     </div>

app/templates/search/start.html

@@ -55,7 +55,7 @@
                         <h6 class="mt-5">{{ _('Trying to add a communitiy or post from another instance?') }} </h6>
                         <p>{{ _('In many types of federated platforms you can put a URL of a post or community into the search in order to add it to your local instance. In PieFed the search is just for searching.') }}</p>
                         <p><a href="{{ url_for('community.add_remote') }}" class="btn btn-primary">{{ _('Add remote community') }}</a></p>
-                        <p>{{ _('To add a post from a remote instance, find the community in PieFed then look for the "Retrieve a post from the original server" link.') }}</p>
+                        <p><a href="{{ url_for('search.retrieve_remote_post') }}" class="btn btn-primary">{{ _('Retrieve remote post') }}</a></p>
                     </div>
                 </div>
             </div>