Add hashing for activity ids

crates/apub/activities/Cargo.toml

@@ -50,6 +50,7 @@ serde_with.workspace = true
 enum_delegate = "0.2.0"
 either = { workspace = true }
 lemmy_diesel_utils = { workspace = true }
+md5 = "0.8.0"
 
 [dev-dependencies]
 

crates/apub/activities/src/block/block_user.rs

@@ -56,7 +56,7 @@ impl BlockUser {
       kind: BlockType::Block,
       remove_data,
       summary: Some(reason),
-      id: generate_activity_id(BlockType::Block, context)?,
+      id: generate_activity_id(BlockType::Block, None, context)?,
       end_time: expires,
       audience: target.as_ref().right().map(|c| c.ap_id.clone().into()),
     })

crates/apub/activities/src/block/undo_block_user.rs

@@ -47,7 +47,7 @@ impl UndoBlockUser {
     let block = BlockUser::new(target, user, mod_, None, reason, None, context).await?;
     let to = to(target)?;
 
-    let id = generate_activity_id(UndoType::Undo, context)?;
+    let id = generate_activity_id(UndoType::Undo, None, context)?;
     let undo = UndoBlockUser {
       actor: mod_.id().clone().into(),
       to,

crates/apub/activities/src/community/announce.rs

@@ -82,15 +82,19 @@ impl AnnounceActivity {
   pub fn new(
     object: RawAnnouncableActivities,
     community: &ApubCommunity,
+    object_id: Option<&Url>,
     context: &Data<LemmyContext>,
   ) -> LemmyResult<AnnounceActivity> {
     let inner_kind = object
       .other
       .get("type")
       .and_then(serde_json::Value::as_str)
       .unwrap_or("other");
-    let id =
-      generate_announce_activity_id(inner_kind, &context.settings().get_protocol_and_hostname())?;
+    let id = generate_announce_activity_id(
+      inner_kind,
+      &context.settings().get_protocol_and_hostname(),
+      object_id,
+    )?;
     Ok(AnnounceActivity {
       actor: community.id().clone().into(),
       to: generate_to(community)?,
@@ -111,7 +115,7 @@ impl AnnounceActivity {
     community: &ApubCommunity,
     context: &Data<LemmyContext>,
   ) -> LemmyResult<()> {
-    let announce = AnnounceActivity::new(object.clone(), community, context)?;
+    let announce = AnnounceActivity::new(object.clone(), community, None, context)?;
     let inboxes = ActivitySendTargets::to_local_community_followers(community.id);
     send_lemmy_activity(context, announce, community, inboxes.clone(), false).await?;
 
@@ -122,14 +126,14 @@ impl AnnounceActivity {
       // Hack: need to convert Page into a format which can be sent as activity, which requires
       //       adding actor field.
       let announcable_page = RawAnnouncableActivities {
-        id: generate_activity_id(AnnounceType::Announce, context)?,
+        id: generate_activity_id(AnnounceType::Announce, None, context)?,
         actor: c.actor.clone().into_inner(),
         other: serde_json::to_value(c.object)?
           .as_object()
           .ok_or(UntranslatedError::Unreachable)?
           .clone(),
       };
-      let announce_compat = AnnounceActivity::new(announcable_page, community, context)?;
+      let announce_compat = AnnounceActivity::new(announcable_page, community, None, context)?;
       send_lemmy_activity(context, announce_compat, community, inboxes, false).await?;
     }
     Ok(())

crates/apub/activities/src/community/collection_add.rs

@@ -46,7 +46,7 @@ impl CollectionAdd {
     actor: &ApubPerson,
     context: &Data<LemmyContext>,
   ) -> LemmyResult<()> {
-    let id = generate_activity_id(AddType::Add, context)?;
+    let id = generate_activity_id(AddType::Add, None, context)?;
     let add = CollectionAdd {
       actor: actor.id().clone().into(),
       to: generate_to(community)?,
@@ -69,7 +69,7 @@ impl CollectionAdd {
     actor: &ApubPerson,
     context: &Data<LemmyContext>,
   ) -> LemmyResult<()> {
-    let id = generate_activity_id(AddType::Add, context)?;
+    let id = generate_activity_id(AddType::Add, None, context)?;
     let add = CollectionAdd {
       actor: actor.id().clone().into(),
       to: generate_to(community)?,

crates/apub/activities/src/community/collection_remove.rs

@@ -43,7 +43,7 @@ impl CollectionRemove {
     actor: &ApubPerson,
     context: &Data<LemmyContext>,
   ) -> LemmyResult<()> {
-    let id = generate_activity_id(RemoveType::Remove, context)?;
+    let id = generate_activity_id(RemoveType::Remove, None, context)?;
     let remove = CollectionRemove {
       actor: actor.id().clone().into(),
       to: generate_to(community)?,
@@ -66,7 +66,7 @@ impl CollectionRemove {
     actor: &ApubPerson,
     context: &Data<LemmyContext>,
   ) -> LemmyResult<()> {
-    let id = generate_activity_id(RemoveType::Remove, context)?;
+    let id = generate_activity_id(RemoveType::Remove, None, context)?;
     let remove = CollectionRemove {
       actor: actor.id().clone().into(),
       to: generate_to(community)?,

crates/apub/activities/src/community/lock.rs

@@ -155,7 +155,7 @@ pub(crate) async fn send_lock(
   context: Data<LemmyContext>,
 ) -> LemmyResult<()> {
   let community: ApubCommunity = post_or_comment_community(&object, &context).await?.into();
-  let id = generate_activity_id(LockType::Lock, &context)?;
+  let id = generate_activity_id(LockType::Lock, None, &context)?;
   let community_id = community.ap_id.inner().clone();
   let ap_id = match object {
     PostOrComment::Left(p) => p.ap_id.clone(),
@@ -175,7 +175,7 @@ pub(crate) async fn send_lock(
   let activity = if locked {
     AnnouncableActivities::Lock(lock)
   } else {
-    let id = generate_activity_id(UndoType::Undo, &context)?;
+    let id = generate_activity_id(UndoType::Undo, None, &context)?;
     let undo = UndoLockPageOrNote {
       actor: lock.actor.clone(),
       to: generate_to(&community)?,

crates/apub/activities/src/community/report.rs

@@ -57,7 +57,7 @@ impl Report {
     context: &Data<LemmyContext>,
   ) -> LemmyResult<Self> {
     let kind = FlagType::Flag;
-    let id = generate_activity_id(kind.clone(), context)?;
+    let id = generate_activity_id(kind.clone(), None, context)?;
     Ok(Report {
       actor: actor.id().clone().into(),
       to: [receiver.id().clone().into()],
@@ -172,7 +172,7 @@ impl Activity for Report {
       // forward to remote mods
       let object_id = self.object.object_id(context).await?;
       let announce = AnnouncableActivities::Report(self);
-      let announce = AnnounceActivity::new(announce.try_into()?, community, context)?;
+      let announce = AnnounceActivity::new(announce.try_into()?, community, None, context)?;
       let inboxes = report_inboxes(object_id, &receiver, &actor, context).await?;
       send_lemmy_activity(context, announce, community, inboxes.clone(), false).await?;
     }

crates/apub/activities/src/community/resolve_report.rs

@@ -47,7 +47,7 @@ impl ResolveReport {
     context: Data<LemmyContext>,
   ) -> LemmyResult<()> {
     let kind = ResolveType::Resolve;
-    let id = generate_activity_id(kind.clone(), &context)?;
+    let id = generate_activity_id(kind.clone(), None, &context)?;
     let object = Report::new(&object_id, report_creator, receiver, None, &context)?;
     let resolve = ResolveReport {
       actor: actor.id().clone().into(),
@@ -106,7 +106,7 @@ impl Activity for ResolveReport {
       // forward to remote mods
       let object_id = self.object.object.object_id(context).await?;
       let announce = AnnouncableActivities::ResolveReport(self);
-      let announce = AnnounceActivity::new(announce.try_into()?, community, context)?;
+      let announce = AnnounceActivity::new(announce.try_into()?, community, None, context)?;
       let inboxes = report_inboxes(object_id, &receiver, &reporter, context).await?;
       send_lemmy_activity(context, announce, community, inboxes.clone(), false).await?;
     }

crates/apub/activities/src/community/update.rs

@@ -36,7 +36,7 @@ pub(crate) async fn send_update_community(
 ) -> LemmyResult<()> {
   let community: ApubCommunity = community.into();
   let actor: ApubPerson = actor.into();
-  let id = generate_activity_id(UpdateType::Update, &context)?;
+  let id = generate_activity_id(UpdateType::Update, None, &context)?;
   let update = Update {
     actor: actor.id().clone().into(),
     to: generate_to(&community)?,
@@ -66,7 +66,7 @@ pub(crate) async fn send_update_multi_community(
 ) -> LemmyResult<()> {
   let multi: ApubMultiCommunity = multi.into();
   let actor: ApubPerson = actor.into();
-  let id = generate_activity_id(UpdateType::Update, &context)?;
+  let id = generate_activity_id(UpdateType::Update, None, &context)?;
   let update = Update {
     actor: actor.id().clone().into(),
     to: vec![multi.ap_id.clone().into(), public()],

crates/apub/activities/src/create_or_update/comment.rs

@@ -55,7 +55,7 @@ impl CreateOrUpdateNote {
       .await?
       .into();
 
-    let id = generate_activity_id(kind.clone(), &context)?;
+    let id = generate_activity_id(kind.clone(), None, &context)?;
     let note = ApubComment(comment).into_json(&context).await?;
 
     let create_or_update = CreateOrUpdateNote {

crates/apub/activities/src/create_or_update/post.rs

@@ -44,9 +44,10 @@ impl CreateOrUpdatePage {
     actor: &ApubPerson,
     community: &ApubCommunity,
     kind: CreateOrUpdateType,
+    object_id: Option<&Url>,
     context: &Data<LemmyContext>,
   ) -> LemmyResult<CreateOrUpdatePage> {
-    let id = generate_activity_id(kind.clone(), context)?;
+    let id = generate_activity_id(kind.clone(), object_id, context)?;
     Ok(CreateOrUpdatePage {
       actor: actor.id().clone().into(),
       to: generate_to(community)?,
@@ -70,8 +71,22 @@ impl CreateOrUpdatePage {
       .await?
       .into();
 
+    // get object_id for activity id generation
+    let post_ap_id = (*post.ap_id.0).clone();
+    let object_id = match kind {
+      // for Create, use the post's ap id
+      CreateOrUpdateType::Create => Some(&post_ap_id),
+      // for Update, use a timestamp to ensure each Update activity is unique
+      CreateOrUpdateType::Update => {
+        let timestamp = post.updated_at.unwrap_or(post.published_at); // use the latest timestamp
+        let mut seed_url = post_ap_id;
+        seed_url.set_fragment(Some(&timestamp.to_rfc3339()));
+        Some(&seed_url.clone())
+      }
+    };
+
     let create_or_update =
-      CreateOrUpdatePage::new(post.into(), &person, &community, kind, &context).await?;
+      CreateOrUpdatePage::new(post.into(), &person, &community, kind, object_id, &context).await?;
     let inboxes = tagged_user_inboxes(&create_or_update.object.tag, &context).await?;
     let activity = AnnouncableActivities::CreateOrUpdatePost(create_or_update);
     send_activity_in_community(activity, &person, &community, inboxes, false, &context).await?;

crates/apub/activities/src/create_or_update/private_message.rs

@@ -24,7 +24,7 @@ pub(crate) async fn send_create_or_update_pm(
   let actor: ApubPerson = pm_view.creator.into();
   let recipient: ApubPerson = pm_view.recipient.into();
 
-  let id = generate_activity_id(kind.clone(), &context)?;
+  let id = generate_activity_id(kind.clone(), None, &context)?;
   let create_or_update = CreateOrUpdatePrivateMessage {
     id: id.clone(),
     actor: actor.id().clone().into(),

crates/apub/activities/src/deletion/delete.rs

@@ -82,7 +82,7 @@ impl Delete {
     with_replies: Option<bool>,
     context: &Data<LemmyContext>,
   ) -> LemmyResult<Delete> {
-    let id = generate_activity_id(DeleteType::Delete, context)?;
+    let id = generate_activity_id(DeleteType::Delete, None, context)?;
     let cc: Option<Url> = community.map(|c| c.ap_id.clone().into());
     Ok(Delete {
       actor: actor.ap_id.clone().into(),

crates/apub/activities/src/deletion/undo_delete.rs

@@ -72,7 +72,7 @@ impl UndoDelete {
       context,
     )?;
 
-    let id = generate_activity_id(UndoType::Undo, context)?;
+    let id = generate_activity_id(UndoType::Undo, None, context)?;
     let cc: Option<Url> = community.map(|c| c.ap_id.clone().into());
     Ok(UndoDelete {
       actor: actor.ap_id.clone().into(),

crates/apub/activities/src/following/accept.rs

@@ -27,7 +27,7 @@ impl AcceptFollow {
       to: Some([person.id().clone().into()]),
       object: follow,
       kind: AcceptType::Accept,
-      id: generate_activity_id(AcceptType::Accept, context)?,
+      id: generate_activity_id(AcceptType::Accept, None, context)?,
     };
     let inbox = ActivitySendTargets::to_inbox(person.shared_inbox_or_inbox());
     send_lemmy_activity(context, accept, &target, inbox, true).await

crates/apub/activities/src/following/follow.rs

@@ -40,7 +40,7 @@ impl Follow {
       object: target.id().clone().into(),
       to: Some([target.id().clone().into()]),
       kind: FollowType::Follow,
-      id: generate_activity_id(FollowType::Follow, context)?,
+      id: generate_activity_id(FollowType::Follow, None, context)?,
     })
   }
 

crates/apub/activities/src/following/mod.rs

@@ -51,7 +51,7 @@ pub async fn send_accept_or_reject_follow(
     to: Some([community.ap_id.clone().into()]),
     object: community.ap_id.into(),
     kind: FollowType::Follow,
-    id: generate_activity_id(FollowType::Follow, context)?,
+    id: generate_activity_id(FollowType::Follow, None, context)?,
   };
   if accepted {
     AcceptFollow::send(follow, context).await

crates/apub/activities/src/following/reject.rs

@@ -27,7 +27,7 @@ impl RejectFollow {
       to: Some([person.id().clone().into()]),
       object: follow,
       kind: RejectType::Reject,
-      id: generate_activity_id(RejectType::Reject, context)?,
+      id: generate_activity_id(RejectType::Reject, None, context)?,
     };
     let inbox = ActivitySendTargets::to_inbox(person.shared_inbox_or_inbox());
     send_activity_from_user_or_community_or_multi(context, reject, user_or_community, inbox).await

crates/apub/activities/src/following/undo_follow.rs

@@ -39,7 +39,7 @@ impl UndoFollow {
       to: Some([target.id().clone().into()]),
       object,
       kind: UndoType::Undo,
-      id: generate_activity_id(UndoType::Undo, context)?,
+      id: generate_activity_id(UndoType::Undo, None, context)?,
     };
     let inbox = ActivitySendTargets::to_inbox(target.shared_inbox_or_inbox());
     send_lemmy_activity(context, undo, actor, inbox, true).await

crates/apub/activities/src/lib.rs

@@ -82,30 +82,50 @@ pub(crate) fn check_community_deleted_or_removed(community: &Community) -> Lemmy
 
 /// Generate a unique ID for an activity, in the format:
 /// `http(s)://example.com/receive/create/202daf0a-1489-45df-8d2e-c8a3173fed36`
-fn generate_activity_id<T>(kind: T, context: &LemmyContext) -> Result<Url, ParseError>
+fn generate_activity_id<T>(
+  kind: T,
+  object_id: Option<&Url>,
+  context: &LemmyContext,
+) -> Result<Url, ParseError>
 where
   T: ToString,
 {
-  let id = format!(
-    "{}/activities/{}/{}",
-    &context.settings().get_protocol_and_hostname(),
-    kind.to_string().to_lowercase(),
-    Uuid::new_v4()
-  );
+  let hostname = context.settings().get_protocol_and_hostname();
+  let kind_str = kind.to_string().to_lowercase();
+
+  let uuid_str = if let Some(o) = object_id {
+    let input = format!("{}:{}", kind_str, o.as_str());
+    Uuid::from_bytes(md5::compute(input).0).to_string()
+  } else {
+    Uuid::new_v4().to_string()
+  };
+
+  let id = format!("{}/activities/{}/{}", hostname, kind_str, uuid_str);
   Url::parse(&id)
 }
 
 /// like generate_activity_id but also add the inner kind for easier debugging
 fn generate_announce_activity_id(
   inner_kind: &str,
   protocol_and_hostname: &str,
+  object_id: Option<&Url>,
 ) -> Result<Url, ParseError> {
+  let inner_kind_str = inner_kind.to_lowercase();
+
+  let uuid_str = if let Some(o) = object_id {
+    // add "announce:" in front to avoid collision with generate_activity_id
+    let input = format!("announce:{}:{}", inner_kind_str, o.as_str());
+    Uuid::from_bytes(md5::compute(input).0).to_string()
+  } else {
+    Uuid::new_v4().to_string()
+  };
+
   let id = format!(
     "{}/activities/{}/{}/{}",
     protocol_and_hostname,
     AnnounceType::Announce.to_string().to_lowercase(),
-    inner_kind.to_lowercase(),
-    Uuid::new_v4()
+    inner_kind_str,
+    uuid_str
   );
   Url::parse(&id)
 }

crates/apub/activities/src/voting/undo_vote.rs

@@ -29,7 +29,7 @@ impl UndoVote {
       actor: actor.id().clone().into(),
       object: vote,
       kind: UndoType::Undo,
-      id: generate_activity_id(UndoType::Undo, context)?,
+      id: generate_activity_id(UndoType::Undo, None, context)?,
       audience: Some(community.ap_id.clone().into()),
     })
   }

crates/apub/activities/src/voting/vote.rs

@@ -31,7 +31,7 @@ impl Vote {
       actor: actor.id().clone().into(),
       object: object_id,
       kind: kind.clone(),
-      id: generate_activity_id(kind, context)?,
+      id: generate_activity_id(kind, None, context)?,
       audience: Some(community.ap_id.clone().into()),
     })
   }