Merge branch 'feature/rejectnonpublic' into 'develop'

Add MRF to drop all posts with "followers-only" or "direct" privacy settings

See merge request pleroma/pleroma!202

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

@@ -0,0 +1,29 @@
+defmodule Pleroma.Web.ActivityPub.MRF.RejectNonPublic do
+  alias Pleroma.User
+  @behaviour Pleroma.Web.ActivityPub.MRF
+
+  @impl true
+  def filter(object) do
+    if object["type"] == "Create" do
+      user = User.get_cached_by_ap_id(object["actor"])
+      public = "https://www.w3.org/ns/activitystreams#Public"
+
+      # Determine visibility
+      visibility =
+        cond do
+          public in object["to"] -> "public"
+          public in object["cc"] -> "unlisted"
+          user.follower_address in object["to"] -> "followers"
+          true -> "direct"
+        end
+
+      case visibility do
+        "public" -> {:ok, object}
+        "unlisted" -> {:ok, object}
+        _ -> {:reject, nil}
+      end
+    else
+      {:ok, object}
+    end
+  end
+end