Added MRF.QuietReply which prevents replies to public posts from being published to the timelines

changelog.d/mrf-quietreply.add

@@ -0,0 +1 @@
+Added MRF.QuietReply which prevents replies to public posts from being published to the timelines

lib/pleroma/web/activity_pub/mrf/quiet_reply.ex

@@ -0,0 +1,55 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.QuietReply do
+  require Pleroma.Constants
+
+  alias Pleroma.User
+
+  @behaviour Pleroma.Web.ActivityPub.MRF.Policy
+
+  @impl true
+  def history_awareness, do: :auto
+
+  @impl true
+  def filter(
+        %{
+          "type" => "Create",
+          "object" => %{
+            "actor" => actor,
+            "type" => "Note",
+            "to" => to,
+            "cc" => cc,
+            "inReplyTo" => in_reply_to
+          }
+        } = object
+      ) do
+    with true <- is_binary(in_reply_to),
+         false <- match?([], cc),
+         %User{follower_address: followers_collection, local: true} <-
+           User.get_by_ap_id(actor) do
+      updated_to =
+        to
+        |> Kernel.++([followers_collection])
+        |> Kernel.--([Pleroma.Constants.as_public()])
+
+      updated_cc = [Pleroma.Constants.as_public()]
+
+      updated_object =
+        object
+        |> put_in(["object", "to"], updated_to)
+        |> put_in(["object", "cc"], updated_cc)
+
+      {:ok, updated_object}
+    else
+      _ -> {:ok, object}
+    end
+  end
+
+  @impl true
+  def filter(object), do: {:ok, object}
+
+  @impl true
+  def describe, do: {:ok, %{}}
+end

test/pleroma/web/activity_pub/mrf/quiet_reply_test.exs

@@ -0,0 +1,103 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.QuietReplyTest do
+  use Pleroma.DataCase
+  import Pleroma.Factory
+
+  require Pleroma.Constants
+
+  alias Pleroma.Object
+  alias Pleroma.Web.ActivityPub.MRF.QuietReply
+  alias Pleroma.Web.CommonAPI
+
+  test "replying to public post is forced to be quiet" do
+    batman = insert(:user, nickname: "batman")
+    robin = insert(:user, nickname: "robin")
+
+    {:ok, post} = CommonAPI.post(batman, %{status: "To the Batmobile!"})
+
+    reply = %{
+      "type" => "Create",
+      "actor" => robin.ap_id,
+      "object" => %{
+        "type" => "Note",
+        "actor" => robin.ap_id,
+        "content" => "@batman Wait up, I forgot my spandex!",
+        "to" => [
+          batman.ap_id,
+          Pleroma.Constants.as_public()
+        ],
+        "cc" => [robin.follower_address],
+        "inReplyTo" => Object.normalize(post).data["id"]
+      }
+    }
+
+    expected_to = [batman.ap_id, robin.follower_address]
+    expected_cc = [Pleroma.Constants.as_public()]
+
+    assert {:ok, filtered} = QuietReply.filter(reply)
+
+    assert expected_to == filtered["object"]["to"]
+    assert expected_cc == filtered["object"]["cc"]
+  end
+
+  test "replying direct is unmodified" do
+    batman = insert(:user, nickname: "batman")
+    robin = insert(:user, nickname: "robin")
+
+    {:ok, post} = CommonAPI.post(batman, %{status: "To the Batmobile!"})
+
+    reply = %{
+      "type" => "Create",
+      "actor" => robin.ap_id,
+      "object" => %{
+        "type" => "Note",
+        "actor" => robin.ap_id,
+        "content" => "@batman Wait up, I forgot my spandex!",
+        "to" => [batman.ap_id],
+        "cc" => [],
+        "inReplyTo" => Object.normalize(post).data["id"]
+      }
+    }
+
+    assert {:ok, filtered} = QuietReply.filter(reply)
+
+    assert match?(^filtered, reply)
+  end
+
+  test "replying followers-only is unmodified" do
+    batman = insert(:user, nickname: "batman")
+    robin = insert(:user, nickname: "robin")
+
+    {:ok, post} = CommonAPI.post(batman, %{status: "To the Batmobile!"})
+
+    reply = %{
+      "type" => "Create",
+      "actor" => robin.ap_id,
+      "object" => %{
+        "type" => "Note",
+        "actor" => robin.ap_id,
+        "content" => "@batman Wait up, I forgot my spandex!",
+        "to" => [batman.ap_id, robin.follower_address],
+        "cc" => [],
+        "inReplyTo" => Object.normalize(post).data["id"]
+      }
+    }
+
+    assert {:ok, filtered} = QuietReply.filter(reply)
+
+    assert match?(^filtered, reply)
+  end
+
+  test "non-reply posts are unmodified" do
+    batman = insert(:user, nickname: "batman")
+
+    {:ok, post} = CommonAPI.post(batman, %{status: "To the Batmobile!"})
+
+    assert {:ok, filtered} = QuietReply.filter(post)
+
+    assert match?(^filtered, post)
+  end
+end

test/support/factory.ex

@@ -53,6 +53,15 @@ defmodule Pleroma.Factory do
       keys: pem
     }
 
+    attrs = Map.delete(attrs, :domain)
+
+    user
+    |> Map.put(:raw_bio, user.bio)
+    |> merge_attributes(attrs)
+    |> user_urls(attrs)
+  end
+
+  defp user_urls(user, attrs) do
     urls =
       if attrs[:local] == false do
         base_domain = attrs[:domain] || Enum.random(["domain1.com", "domain2.com", "domain3.com"])
@@ -75,12 +84,7 @@ defmodule Pleroma.Factory do
         }
       end
 
-    attrs = Map.delete(attrs, :domain)
+    Map.merge(user, urls)
-
-    user
-    |> Map.put(:raw_bio, user.bio)
-    |> Map.merge(urls)
-    |> merge_attributes(attrs)
   end
 
   def user_relationship_factory(attrs \\ %{}) do