Merge branch 'follower-mrf-again' into 'develop'

Follower mrf again

See merge request pleroma/pleroma!2833

config/config.exs

@@ -374,6 +374,7 @@
   federated_timeline_removal: [],
   report_removal: [],
   reject: [],
+  followers_only: [],
   accept: [],
   avatar_removal: [],
   banner_removal: [],

config/description.exs

@@ -1542,6 +1542,12 @@
         description: "List of instances to only accept activities from (except deletes)",
         suggestions: ["example.com", "*.example.com"]
       },
+      %{
+        key: :followers_only,
+        type: {:list, :string},
+        description: "Force posts from the given instances to be visible by followers only",
+        suggestions: ["example.com", "*.example.com"]
+      },
       %{
         key: :report_removal,
         type: {:list, :string},

docs/configuration/cheatsheet.md

@@ -125,6 +125,7 @@ To add configuration to your config file, you can copy it from the base config.
 * `federated_timeline_removal`: List of instances to remove from Federated (aka The Whole Known Network) Timeline.
 * `reject`: List of instances to reject any activities from.
 * `accept`: List of instances to accept any activities from.
+* `followers_only`: List of instances to decrease post visibility to only the followers, including for DM mentions.
 * `report_removal`: List of instances to reject reports from.
 * `avatar_removal`: List of instances to strip avatars from.
 * `banner_removal`: List of instances to strip banners from.

lib/pleroma/following_relationship.ex

@@ -95,7 +95,11 @@ def followers_query(%User{} = user) do
     |> where([r], r.state == ^:follow_accept)
   end
 
-  def followers_ap_ids(%User{} = user, from_ap_ids \\ nil) do
+  def followers_ap_ids(user, from_ap_ids \\ nil)
+
+  def followers_ap_ids(_, []), do: []
+
+  def followers_ap_ids(%User{} = user, from_ap_ids) do
     query =
       user
       |> followers_query()

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

@@ -7,6 +7,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.SimplePolicy do
   @behaviour Pleroma.Web.ActivityPub.MRF
 
   alias Pleroma.Config
+  alias Pleroma.FollowingRelationship
   alias Pleroma.User
   alias Pleroma.Web.ActivityPub.MRF
 
@@ -108,6 +109,35 @@ defp check_ftl_removal(%{host: actor_host} = _actor_info, object) do
     {:ok, object}
   end
 
+  defp intersection(list1, list2) do
+    list1 -- list1 -- list2
+  end
+
+  defp check_followers_only(%{host: actor_host} = _actor_info, object) do
+    followers_only =
+      Config.get([:mrf_simple, :followers_only])
+      |> MRF.subdomains_regex()
+
+    object =
+      with true <- MRF.subdomain_match?(followers_only, actor_host),
+           user <- User.get_cached_by_ap_id(object["actor"]) do
+        # Don't use Map.get/3 intentionally, these must not be nil
+        fixed_to = object["to"] || []
+        fixed_cc = object["cc"] || []
+
+        to = FollowingRelationship.followers_ap_ids(user, fixed_to)
+        cc = FollowingRelationship.followers_ap_ids(user, fixed_cc)
+
+        object
+        |> Map.put("to", intersection([user.follower_address | to], fixed_to))
+        |> Map.put("cc", intersection([user.follower_address | cc], fixed_cc))
+      else
+        _ -> object
+      end
+
+    {:ok, object}
+  end
+
   defp check_report_removal(%{host: actor_host} = _actor_info, %{"type" => "Flag"} = object) do
     report_removal =
       Config.get([:mrf_simple, :report_removal])
@@ -174,6 +204,7 @@ def filter(%{"actor" => actor} = object) do
          {:ok, object} <- check_media_removal(actor_info, object),
          {:ok, object} <- check_media_nsfw(actor_info, object),
          {:ok, object} <- check_ftl_removal(actor_info, object),
+         {:ok, object} <- check_followers_only(actor_info, object),
          {:ok, object} <- check_report_removal(actor_info, object) do
       {:ok, object}
     else

test/web/activity_pub/mrf/simple_policy_test.exs

@@ -7,6 +7,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.SimplePolicyTest do
   import Pleroma.Factory
   alias Pleroma.Config
   alias Pleroma.Web.ActivityPub.MRF.SimplePolicy
+  alias Pleroma.Web.CommonAPI
 
   setup do:
           clear_config(:mrf_simple,
@@ -15,6 +16,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.SimplePolicyTest do
             federated_timeline_removal: [],
             report_removal: [],
             reject: [],
+            followers_only: [],
             accept: [],
             avatar_removal: [],
             banner_removal: [],
@@ -261,6 +263,64 @@ test "actor has a matching host" do
     end
   end
 
+  describe "when :followers_only" do
+    test "is empty" do
+      Config.put([:mrf_simple, :followers_only], [])
+      {_, ftl_message} = build_ftl_actor_and_message()
+      local_message = build_local_message()
+
+      assert SimplePolicy.filter(ftl_message) == {:ok, ftl_message}
+      assert SimplePolicy.filter(local_message) == {:ok, local_message}
+    end
+
+    test "has a matching host" do
+      actor = insert(:user)
+      following_user = insert(:user)
+      non_following_user = insert(:user)
+
+      {:ok, _, _, _} = CommonAPI.follow(following_user, actor)
+
+      activity = %{
+        "actor" => actor.ap_id,
+        "to" => [
+          "https://www.w3.org/ns/activitystreams#Public",
+          following_user.ap_id,
+          non_following_user.ap_id
+        ],
+        "cc" => [actor.follower_address, "http://foo.bar/qux"]
+      }
+
+      dm_activity = %{
+        "actor" => actor.ap_id,
+        "to" => [
+          following_user.ap_id,
+          non_following_user.ap_id
+        ],
+        "cc" => []
+      }
+
+      actor_domain =
+        activity
+        |> Map.fetch!("actor")
+        |> URI.parse()
+        |> Map.fetch!(:host)
+
+      Config.put([:mrf_simple, :followers_only], [actor_domain])
+
+      assert {:ok, new_activity} = SimplePolicy.filter(activity)
+      assert actor.follower_address in new_activity["cc"]
+      assert following_user.ap_id in new_activity["to"]
+      refute "https://www.w3.org/ns/activitystreams#Public" in new_activity["to"]
+      refute "https://www.w3.org/ns/activitystreams#Public" in new_activity["cc"]
+      refute non_following_user.ap_id in new_activity["to"]
+      refute non_following_user.ap_id in new_activity["cc"]
+
+      assert {:ok, new_dm_activity} = SimplePolicy.filter(dm_activity)
+      assert new_dm_activity["to"] == [following_user.ap_id]
+      assert new_dm_activity["cc"] == []
+    end
+  end
+
   describe "when :accept" do
     test "is empty" do
       Config.put([:mrf_simple, :accept], [])