5 files changed, 37 insertions, 11 deletions
diff --git a/lib/pleroma/activity/ir/topics.ex b/lib/pleroma/activity/ir/topics.ex
index 9e65bedad..fe2e8cb5c 100644
--- a/lib/pleroma/activity/ir/topics.ex
+++ b/lib/pleroma/activity/ir/topics.ex
@@ -40,7 +40,8 @@ defmodule Pleroma.Activity.Ir.Topics do
   end
 
   defp item_creation_tags(tags, object, %{data: %{"type" => "Create"}} = activity) do
-    tags ++ hashtags_to_topics(object) ++ attachment_topics(object, activity)
+    tags ++
+      remote_topics(activity) ++ hashtags_to_topics(object) ++ attachment_topics(object, activity)
   end
 
   defp item_creation_tags(tags, _, _) do
@@ -55,9 +56,19 @@ defmodule Pleroma.Activity.Ir.Topics do
 
   defp hashtags_to_topics(_), do: []
 
+  defp remote_topics(%{local: true}), do: []
+
+  defp remote_topics(%{actor: actor}) when is_binary(actor),
+    do: ["public:remote:" <> URI.parse(actor).host]
+
+  defp remote_topics(_), do: []
+
   defp attachment_topics(%{data: %{"attachment" => []}}, _act), do: []
 
   defp attachment_topics(_object, %{local: true}), do: ["public:media", "public:local:media"]
 
+  defp attachment_topics(_object, %{actor: actor}) when is_binary(actor),
+    do: ["public:media", "public:remote:media:" <> URI.parse(actor).host]
+
   defp attachment_topics(_object, _act), do: ["public:media"]
 end
diff --git a/lib/pleroma/web/activity_pub/activity_pub.ex b/lib/pleroma/web/activity_pub/activity_pub.ex
index 13869f897..d8f685d38 100644
--- a/lib/pleroma/web/activity_pub/activity_pub.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub.ex
@@ -937,16 +937,11 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
 
   defp restrict_muted_reblogs(query, _), do: query
 
-  defp restrict_instance(query, %{instance: instance}) do
-    users =
-      from(
-        u in User,
-        select: u.ap_id,
-        where: fragment("? LIKE ?", u.nickname, ^"%@#{instance}")
-      )
-      |> Repo.all()
-
-    from(activity in query, where: activity.actor in ^users)
+  defp restrict_instance(query, %{instance: instance}) when is_binary(instance) do
+    from(
+      activity in query,
+      where: fragment("split_part(actor::text, '/'::text, 3) = ?", ^instance)
+    )
   end
 
   defp restrict_instance(query, _), do: query
diff --git a/lib/pleroma/web/api_spec/operations/timeline_operation.ex b/lib/pleroma/web/api_spec/operations/timeline_operation.ex
index 1b5ad796f..95720df9f 100644
--- a/lib/pleroma/web/api_spec/operations/timeline_operation.ex
+++ b/lib/pleroma/web/api_spec/operations/timeline_operation.ex
@@ -59,6 +59,7 @@ defmodule Pleroma.Web.ApiSpec.TimelineOperation do
       security: [%{"oAuth" => ["read:statuses"]}],
       parameters: [
         local_param(),
+        instance_param(),
         only_media_param(),
         with_muted_param(),
         exclude_visibilities_param(),
@@ -158,6 +159,15 @@ defmodule Pleroma.Web.ApiSpec.TimelineOperation do
     )
   end
 
+  defp instance_param do
+    Operation.parameter(
+      :instance,
+      :query,
+      %Schema{type: :string},
+      "Show only statuses from the given domain"
+    )
+  end
+
   defp with_muted_param do
     Operation.parameter(:with_muted, :query, BooleanLike, "Include activities by muted users")
   end
diff --git a/lib/pleroma/web/mastodon_api/controllers/timeline_controller.ex b/lib/pleroma/web/mastodon_api/controllers/timeline_controller.ex
index 7a5c80e01..ac96520a3 100644
--- a/lib/pleroma/web/mastodon_api/controllers/timeline_controller.ex
+++ b/lib/pleroma/web/mastodon_api/controllers/timeline_controller.ex
@@ -111,6 +111,7 @@ defmodule Pleroma.Web.MastodonAPI.TimelineController do
         |> Map.put(:blocking_user, user)
         |> Map.put(:muting_user, user)
         |> Map.put(:reply_filtering_user, user)
+        |> Map.put(:instance, params[:instance])
         |> ActivityPub.fetch_public_activities()
 
       conn
diff --git a/lib/pleroma/web/streamer.ex b/lib/pleroma/web/streamer.ex
index d618dfe54..71fe27c89 100644
--- a/lib/pleroma/web/streamer.ex
+++ b/lib/pleroma/web/streamer.ex
@@ -57,6 +57,15 @@ defmodule Pleroma.Web.Streamer do
     {:ok, "hashtag:" <> tag}
   end
 
+  # Allow remote instance streams.
+  def get_topic("public:remote", _user, _oauth_token, %{"instance" => instance} = _params) do
+    {:ok, "public:remote:" <> instance}
+  end
+
+  def get_topic("public:remote:media", _user, _oauth_token, %{"instance" => instance} = _params) do
+    {:ok, "public:remote:media:" <> instance}
+  end
+
   # Expand user streams.
   def get_topic(
         stream,