5 files changed, 78 insertions, 11 deletions
diff --git a/lib/pleroma/web/activity_pub/activity_pub.ex b/lib/pleroma/web/activity_pub/activity_pub.ex
index c0e3d1478..55315d66e 100644
--- a/lib/pleroma/web/activity_pub/activity_pub.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub.ex
@@ -189,6 +189,22 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     end)
   end
 
+  def stream_out_participations(%Object{data: %{"context" => context}}, user) do
+    with %Conversation{} = conversation <- Conversation.get_for_ap_id(context),
+         conversation = Repo.preload(conversation, :participations),
+         last_activity_id =
+           fetch_latest_activity_id_for_context(conversation.ap_id, %{
+             "user" => user,
+             "blocking_user" => user
+           }) do
+      if last_activity_id do
+        stream_out_participations(conversation.participations)
+      end
+    end
+  end
+
+  def stream_out_participations(_, _), do: :noop
+
   def stream_out(activity) do
     public = "https://www.w3.org/ns/activitystreams#Public"
 
@@ -401,7 +417,8 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
            "to" => to,
            "deleted_activity_id" => activity && activity.id
          },
-         {:ok, activity} <- insert(data, local),
+         {:ok, activity} <- insert(data, local, false),
+         stream_out_participations(object, user),
          _ <- decrease_replies_count_if_reply(object),
          # Changing note count prior to enqueuing federation task in order to avoid
          # race conditions on updating user.info
diff --git a/lib/pleroma/web/activity_pub/mrf/anti_link_spam_policy.ex b/lib/pleroma/web/activity_pub/mrf/anti_link_spam_policy.ex
new file mode 100644
index 000000000..2da3eac2f
--- /dev/null
+++ b/lib/pleroma/web/activity_pub/mrf/anti_link_spam_policy.ex
@@ -0,0 +1,48 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.AntiLinkSpamPolicy do
+  alias Pleroma.User
+
+  require Logger
+
+  # has the user successfully posted before?
+  defp old_user?(%User{} = u) do
+    u.info.note_count > 0 || u.info.follower_count > 0
+  end
+
+  # does the post contain links?
+  defp contains_links?(%{"content" => content} = _object) do
+    content
+    |> Floki.filter_out("a.mention,a.hashtag,a[rel~=\"tag\"],a.zrl")
+    |> Floki.attribute("a", "href")
+    |> length() > 0
+  end
+
+  defp contains_links?(_), do: false
+
+  def filter(%{"type" => "Create", "actor" => actor, "object" => object} = message) do
+    with {:ok, %User{} = u} <- User.get_or_fetch_by_ap_id(actor),
+         {:contains_links, true} <- {:contains_links, contains_links?(object)},
+         {:old_user, true} <- {:old_user, old_user?(u)} do
+      {:ok, message}
+    else
+      {:contains_links, false} ->
+        {:ok, message}
+
+      {:old_user, false} ->
+        {:reject, nil}
+
+      {:error, _} ->
+        {:reject, nil}
+
+      e ->
+        Logger.warn("[MRF anti-link-spam] WTF: unhandled error #{inspect(e)}")
+        {:reject, nil}
+    end
+  end
+
+  # in all other cases, pass through
+  def filter(message), do: {:ok, message}
+end
diff --git a/lib/pleroma/web/activity_pub/publisher.ex b/lib/pleroma/web/activity_pub/publisher.ex
index 8f1399ce6..a05e03263 100644
--- a/lib/pleroma/web/activity_pub/publisher.ex
+++ b/lib/pleroma/web/activity_pub/publisher.ex
@@ -88,7 +88,7 @@ defmodule Pleroma.Web.ActivityPub.Publisher do
       true
     else
       inbox_info = URI.parse(inbox)
-      !Enum.member?(Pleroma.Config.get([:instance, :quarantined_instances], []), inbox_info.host)
+      !Enum.member?(Config.get([:instance, :quarantined_instances], []), inbox_info.host)
     end
   end
 
diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index ff031a16e..3bb8b40b5 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -339,7 +339,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   def fix_type(%{"inReplyTo" => reply_id} = object) when is_binary(reply_id) do
     reply = Object.normalize(reply_id)
 
-    if reply.data["type"] == "Question" and object["name"] do
+    if reply && (reply.data["type"] == "Question" and object["name"]) do
       Map.put(object, "type", "Answer")
     else
       object
diff --git a/lib/pleroma/web/activity_pub/utils.ex b/lib/pleroma/web/activity_pub/utils.ex
index 10ff572a2..514266cee 100644
--- a/lib/pleroma/web/activity_pub/utils.ex
+++ b/lib/pleroma/web/activity_pub/utils.ex
@@ -151,16 +151,18 @@ defmodule Pleroma.Web.ActivityPub.Utils do
 
   def create_context(context) do
     context = context || generate_id("contexts")
-    changeset = Object.context_mapping(context)
 
-    case Repo.insert(changeset) do
-      {:ok, object} ->
-        object
+    # Ecto has problems accessing the constraint inside the jsonb,
+    # so we explicitly check for the existed object before insert
+    object = Object.get_cached_by_ap_id(context)
 
-      # This should be solved by an upsert, but it seems ecto
-      # has problems accessing the constraint inside the jsonb.
-      {:error, _} ->
-        Object.get_cached_by_ap_id(context)
+    with true <- is_nil(object),
+         changeset <- Object.context_mapping(context),
+         {:ok, inserted_object} <- Repo.insert(changeset) do
+      inserted_object
+    else
+      _ ->
+        object
     end
   end