Fix federation of community deletion/removal (fixes #1253)

lemmy_api/src/community.rs

@@ -327,9 +327,9 @@ impl Perform for DeleteCommunity {
 
     // Send apub messages
     if deleted {
-      updated_community.send_delete(&user, context).await?;
+      updated_community.send_delete(context).await?;
     } else {
-      updated_community.send_undo_delete(&user, context).await?;
+      updated_community.send_undo_delete(context).await?;
     }
 
     let edit_id = data.edit_id;
@@ -395,9 +395,9 @@ impl Perform for RemoveCommunity {
 
     // Apub messages
     if removed {
-      updated_community.send_remove(&user, context).await?;
+      updated_community.send_remove(context).await?;
     } else {
-      updated_community.send_undo_remove(&user, context).await?;
+      updated_community.send_undo_remove(context).await?;
     }
 
     let edit_id = data.edit_id;

lemmy_apub/src/activities/send/community.rs

@@ -4,7 +4,6 @@ use crate::{
   check_is_apub_id_valid,
   fetcher::get_or_fetch_and_upsert_user,
   ActorType,
-  ToApub,
 };
 use activitystreams::{
   activity::{
@@ -23,7 +22,7 @@ use activitystreams::{
 };
 use anyhow::Context;
 use itertools::Itertools;
-use lemmy_db::{community::Community, community_view::CommunityFollowerView, user::User_, DbPool};
+use lemmy_db::{community::Community, community_view::CommunityFollowerView, DbPool};
 use lemmy_structs::blocking;
 use lemmy_utils::{location_info, settings::Settings, LemmyError};
 use lemmy_websocket::LemmyContext;
@@ -85,10 +84,8 @@ impl ActorType for Community {
   }
 
   /// If the creator of a community deletes the community, send this to all followers.
-  async fn send_delete(&self, creator: &User_, context: &LemmyContext) -> Result<(), LemmyError> {
-    let group = self.to_apub(context.pool()).await?;
-
-    let mut delete = Delete::new(creator.actor_id.to_owned(), group.into_any_base()?);
+  async fn send_delete(&self, context: &LemmyContext) -> Result<(), LemmyError> {
+    let mut delete = Delete::new(self.actor_id()?, self.actor_id()?);
     delete
       .set_context(activitystreams::context())
       .set_id(generate_activity_id(DeleteType::Delete)?)
@@ -100,21 +97,15 @@ impl ActorType for Community {
   }
 
   /// If the creator of a community reverts the deletion of a community, send this to all followers.
-  async fn send_undo_delete(
-    &self,
-    creator: &User_,
-    context: &LemmyContext,
-  ) -> Result<(), LemmyError> {
-    let group = self.to_apub(context.pool()).await?;
-
-    let mut delete = Delete::new(creator.actor_id.to_owned(), group.into_any_base()?);
+  async fn send_undo_delete(&self, context: &LemmyContext) -> Result<(), LemmyError> {
+    let mut delete = Delete::new(self.actor_id()?, self.actor_id()?);
     delete
       .set_context(activitystreams::context())
       .set_id(generate_activity_id(DeleteType::Delete)?)
       .set_to(public())
       .set_many_ccs(vec![self.get_followers_url()?]);
 
-    let mut undo = Undo::new(creator.actor_id.to_owned(), delete.into_any_base()?);
+    let mut undo = Undo::new(self.actor_id()?, delete.into_any_base()?);
     undo
       .set_context(activitystreams::context())
       .set_id(generate_activity_id(UndoType::Undo)?)
@@ -126,8 +117,8 @@ impl ActorType for Community {
   }
 
   /// If an admin removes a community, send this to all followers.
-  async fn send_remove(&self, mod_: &User_, context: &LemmyContext) -> Result<(), LemmyError> {
-    let mut remove = Remove::new(mod_.actor_id.to_owned(), self.actor_id()?);
+  async fn send_remove(&self, context: &LemmyContext) -> Result<(), LemmyError> {
+    let mut remove = Remove::new(self.actor_id()?, self.actor_id()?);
     remove
       .set_context(activitystreams::context())
       .set_id(generate_activity_id(RemoveType::Remove)?)
@@ -139,8 +130,8 @@ impl ActorType for Community {
   }
 
   /// If an admin reverts the removal of a community, send this to all followers.
-  async fn send_undo_remove(&self, mod_: &User_, context: &LemmyContext) -> Result<(), LemmyError> {
-    let mut remove = Remove::new(mod_.actor_id.to_owned(), self.actor_id()?);
+  async fn send_undo_remove(&self, context: &LemmyContext) -> Result<(), LemmyError> {
+    let mut remove = Remove::new(self.actor_id()?, self.actor_id()?);
     remove
       .set_context(activitystreams::context())
       .set_id(generate_activity_id(RemoveType::Remove)?)
@@ -148,7 +139,7 @@ impl ActorType for Community {
       .set_many_ccs(vec![self.get_followers_url()?]);
 
     // Undo that fake activity
-    let mut undo = Undo::new(mod_.actor_id.to_owned(), remove.into_any_base()?);
+    let mut undo = Undo::new(self.actor_id()?, remove.into_any_base()?);
     undo
       .set_context(activitystreams::context())
       .set_id(generate_activity_id(LikeType::Like)?)

lemmy_apub/src/activities/send/user.rs

@@ -94,27 +94,19 @@ impl ActorType for User_ {
     unimplemented!()
   }
 
-  async fn send_delete(&self, _creator: &User_, _context: &LemmyContext) -> Result<(), LemmyError> {
+  async fn send_delete(&self, _context: &LemmyContext) -> Result<(), LemmyError> {
     unimplemented!()
   }
 
-  async fn send_undo_delete(
-    &self,
-    _creator: &User_,
-    _context: &LemmyContext,
-  ) -> Result<(), LemmyError> {
+  async fn send_undo_delete(&self, _context: &LemmyContext) -> Result<(), LemmyError> {
     unimplemented!()
   }
 
-  async fn send_remove(&self, _creator: &User_, _context: &LemmyContext) -> Result<(), LemmyError> {
+  async fn send_remove(&self, _context: &LemmyContext) -> Result<(), LemmyError> {
     unimplemented!()
   }
 
-  async fn send_undo_remove(
-    &self,
-    _creator: &User_,
-    _context: &LemmyContext,
-  ) -> Result<(), LemmyError> {
+  async fn send_undo_remove(&self, _context: &LemmyContext) -> Result<(), LemmyError> {
     unimplemented!()
   }
 

lemmy_apub/src/fetcher.rs

@@ -251,10 +251,14 @@ pub(crate) async fn get_or_fetch_and_upsert_user(
     Ok(u) if !u.local && should_refetch_actor(u.last_refreshed_at) => {
       debug!("Fetching and updating from remote user: {}", apub_id);
       let person =
-        fetch_remote_object::<PersonExt>(context.client(), apub_id, recursion_counter).await?;
+        fetch_remote_object::<PersonExt>(context.client(), apub_id, recursion_counter).await;
+      // If fetching failed, return the existing data.
+      if person.is_err() {
+        return Ok(u);
+      }
 
       let mut uf = UserForm::from_apub(
-        &person,
+        &person?,
         context,
         Some(apub_id.to_owned()),
         recursion_counter,
@@ -320,7 +324,7 @@ pub(crate) async fn get_or_fetch_and_upsert_community(
   match community {
     Ok(c) if !c.local && should_refetch_actor(c.last_refreshed_at) => {
       debug!("Fetching and updating from remote community: {}", apub_id);
-      fetch_remote_community(apub_id, context, Some(c.id), recursion_counter).await
+      fetch_remote_community(apub_id, context, Some(c), recursion_counter).await
     }
     Ok(c) => Ok(c),
     Err(NotFound {}) => {
@@ -331,17 +335,24 @@ pub(crate) async fn get_or_fetch_and_upsert_community(
   }
 }
 
-/// Request a community by apub ID from a remote instance, including moderators. If `community_id`,
+/// Request a community by apub ID from a remote instance, including moderators. If `old_community`,
 /// is set, this is an update for a community which is already known locally. If not, we don't know
 /// the community yet and also pull the outbox, to get some initial posts.
 async fn fetch_remote_community(
   apub_id: &Url,
   context: &LemmyContext,
-  community_id: Option<i32>,
+  old_community: Option<Community>,
   recursion_counter: &mut i32,
 ) -> Result<Community, LemmyError> {
-  let group = fetch_remote_object::<GroupExt>(context.client(), apub_id, recursion_counter).await?;
+  let group = fetch_remote_object::<GroupExt>(context.client(), apub_id, recursion_counter).await;
+  // If fetching failed, return the existing data.
+  if let Some(ref c) = old_community {
+    if group.is_err() {
+      return Ok(c.to_owned());
+    }
+  }
 
+  let group = group?;
   let cf =
     CommunityForm::from_apub(&group, context, Some(apub_id.to_owned()), recursion_counter).await?;
   let community = blocking(context.pool(), move |conn| Community::upsert(conn, &cf)).await??;
@@ -364,7 +375,7 @@ async fn fetch_remote_community(
   }
 
   // TODO: need to make this work to update mods of existing communities
-  if community_id.is_none() {
+  if old_community.is_none() {
     let community_id = community.id;
     blocking(context.pool(), move |conn| {
       for mod_ in creator_and_moderators {

lemmy_apub/src/lib.rs

@@ -189,15 +189,11 @@ pub trait ActorType {
     context: &LemmyContext,
   ) -> Result<(), LemmyError>;
 
-  async fn send_delete(&self, creator: &User_, context: &LemmyContext) -> Result<(), LemmyError>;
-  async fn send_undo_delete(
-    &self,
-    creator: &User_,
-    context: &LemmyContext,
-  ) -> Result<(), LemmyError>;
+  async fn send_delete(&self, context: &LemmyContext) -> Result<(), LemmyError>;
+  async fn send_undo_delete(&self, context: &LemmyContext) -> Result<(), LemmyError>;
 
-  async fn send_remove(&self, mod_: &User_, context: &LemmyContext) -> Result<(), LemmyError>;
-  async fn send_undo_remove(&self, mod_: &User_, context: &LemmyContext) -> Result<(), LemmyError>;
+  async fn send_remove(&self, context: &LemmyContext) -> Result<(), LemmyError>;
+  async fn send_undo_remove(&self, context: &LemmyContext) -> Result<(), LemmyError>;
 
   async fn send_announce(
     &self,