Pleroma/lib/pleroma/web/activity_pub/mrf/anti_followbot_policy.ex

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2019-01-24 10:35:19 +01:00
# 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.AntiFollowbotPolicy do
alias Pleroma.User
@moduledoc "Prevent followbots from following with a bit of heuristic"
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@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 always be a binary string because it's generated by Pleroma.
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nick_score =
nickname
|> String.downcase()
|> score_nickname()
# displayname will either be a binary string or nil, if a displayname isn't set.
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name_score =
if is_binary(displayname) do
displayname
|> String.downcase()
|> score_displayname()
else
0.0
end
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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}
end