From d6bd072ea18253aa7d4dd3531e8126db414a5de1 Mon Sep 17 00:00:00 2001
From: Felix Ableitner <me@nutomic.com>
Date: Mon, 22 Mar 2021 15:08:06 +0100
Subject: [PATCH] Make federation compatible with Lemmy v0.9.9

---
 crates/apub/src/objects/comment.rs   |  7 +++++-
 crates/apub/src/objects/community.rs | 37 +++++++++++++++++++++++++---
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/crates/apub/src/objects/comment.rs b/crates/apub/src/objects/comment.rs
index 536190f03..9ed746586 100644
--- a/crates/apub/src/objects/comment.rs
+++ b/crates/apub/src/objects/comment.rs
@@ -26,6 +26,7 @@ use lemmy_db_queries::{Crud, DbPool};
 use lemmy_db_schema::{
   source::{
     comment::{Comment, CommentForm},
+    community::Community,
     person::Person,
     post::Post,
   },
@@ -52,6 +53,9 @@ impl ToApub for Comment {
     let post_id = self.post_id;
     let post = blocking(pool, move |conn| Post::read(conn, post_id)).await??;
 
+    let community_id = post.community_id;
+    let community = blocking(pool, move |conn| Community::read(conn, community_id)).await??;
+
     // Add a vector containing some important info to the "in_reply_to" field
     // [post_ap_id, Option(parent_comment_ap_id)]
     let mut in_reply_to_vec = vec![post.ap_id.into_inner()];
@@ -67,7 +71,8 @@ impl ToApub for Comment {
       .set_many_contexts(lemmy_context()?)
       .set_id(self.ap_id.to_owned().into_inner())
       .set_published(convert_datetime(self.published))
-      .set_to(public())
+      // NOTE: included community id for compatibility with lemmy v0.9.9
+      .set_many_tos(vec![community.actor_id.into_inner(), public()])
       .set_many_in_reply_tos(in_reply_to_vec)
       .set_attributed_to(creator.actor_id.into_inner());
 
diff --git a/crates/apub/src/objects/community.rs b/crates/apub/src/objects/community.rs
index a20af20db..d7e42c4ae 100644
--- a/crates/apub/src/objects/community.rs
+++ b/crates/apub/src/objects/community.rs
@@ -23,11 +23,13 @@ use activitystreams::{
 };
 use activitystreams_ext::Ext2;
 use anyhow::Context;
+use lemmy_api_structs::blocking;
 use lemmy_db_queries::DbPool;
 use lemmy_db_schema::{
   naive_now,
   source::community::{Community, CommunityForm},
 };
+use lemmy_db_views_actor::community_moderator_view::CommunityModeratorView;
 use lemmy_utils::{
   location_info,
   utils::{check_slurs, check_slurs_opt, convert_datetime},
@@ -40,13 +42,25 @@ use url::Url;
 impl ToApub for Community {
   type ApubType = GroupExt;
 
-  async fn to_apub(&self, _pool: &DbPool) -> Result<GroupExt, LemmyError> {
+  async fn to_apub(&self, pool: &DbPool) -> Result<GroupExt, LemmyError> {
+    let id = self.id;
+    let moderators = blocking(pool, move |conn| {
+      CommunityModeratorView::for_community(&conn, id)
+    })
+    .await??;
+    let moderators: Vec<Url> = moderators
+      .into_iter()
+      .map(|m| m.moderator.actor_id.into_inner())
+      .collect();
+
     let mut group = ApObject::new(Group::new());
     group
       .set_many_contexts(lemmy_context()?)
       .set_id(self.actor_id.to_owned().into())
       .set_name(self.title.to_owned())
-      .set_published(convert_datetime(self.published));
+      .set_published(convert_datetime(self.published))
+      // NOTE: included attritubed_to field for compatibility with lemmy v0.9.9
+      .set_many_attributed_tos(moderators);
 
     if let Some(u) = self.updated.to_owned() {
       group.set_updated(convert_datetime(u));
@@ -127,9 +141,24 @@ impl FromApubToForm<GroupExt> for CommunityForm {
     _mod_action_allowed: bool,
   ) -> Result<Self, LemmyError> {
     let moderator_uris = fetch_community_mods(context, group, request_counter).await?;
-    let creator_uri = moderator_uris.first().context(location_info!())?;
+    let creator = if let Some(creator_uri) = moderator_uris.first() {
+      get_or_fetch_and_upsert_person(creator_uri, context, request_counter)
+    } else {
+      // NOTE: code for compatibility with lemmy v0.9.9
+      let creator_uri = group
+        .inner
+        .attributed_to()
+        .map(|a| a.as_many())
+        .flatten()
+        .map(|a| a.first())
+        .flatten()
+        .map(|a| a.as_xsd_any_uri())
+        .flatten()
+        .context(location_info!())?;
+      get_or_fetch_and_upsert_person(creator_uri, context, request_counter)
+    }
+    .await?;
 
-    let creator = get_or_fetch_and_upsert_person(creator_uri, context, request_counter).await?;
     let name = group
       .inner
       .preferred_username()