Remote Timeline: add Streaming support

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

lib/pleroma/web/streamer/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,