# Pleroma: A lightweight social networking server # Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/> # SPDX-License-Identifier: AGPL-3.0-only defmodule Pleroma.Web.ActivityPub.MRF.AntiFollowbotPolicy do alias Pleroma.User @moduledoc "Prevent followbots from following with a bit of heuristic" @behaviour Pleroma.Web.ActivityPub.MRF # XXX: this should become User.normalize_by_ap_id() or similar, really. defp normalize_by_ap_id(%{"id" => id}), do: User.get_cached_by_ap_id(id) defp normalize_by_ap_id(uri) when is_binary(uri), do: User.get_cached_by_ap_id(uri) defp normalize_by_ap_id(_), do: nil defp score_nickname("followbot@" <> _), do: 1.0 defp score_nickname("federationbot@" <> _), do: 1.0 defp score_nickname("federation_bot@" <> _), do: 1.0 defp score_nickname(_), do: 0.0 defp score_displayname("federation bot"), do: 1.0 defp score_displayname("federationbot"), do: 1.0 defp score_displayname("fedibot"), do: 1.0 defp score_displayname(_), do: 0.0 defp determine_if_followbot(%User{nickname: nickname, name: displayname}) do # nickname will be a binary string except when following a relay nick_score = if is_binary(nickname) do nickname |> String.downcase() |> score_nickname() else 0.0 end # displayname will either be a binary string or nil, if a displayname isn't set. name_score = if is_binary(displayname) do displayname |> String.downcase() |> score_displayname() else 0.0 end nick_score + name_score end defp determine_if_followbot(_), do: 0.0 @impl true def filter(%{"type" => "Follow", "actor" => actor_id} = message) do %User{} = actor = normalize_by_ap_id(actor_id) score = determine_if_followbot(actor) # TODO: scan biography data for keywords and score it somehow. if score < 0.8 do {:ok, message} else {:reject, nil} end end @impl true def filter(message), do: {:ok, message} @impl true def describe, do: {:ok, %{}} end