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-rw-r--r--lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex97
1 files changed, 97 insertions, 0 deletions
diff --git a/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex b/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex
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+++ b/lib/pleroma/web/activity_pub/mrf/steal_emoji_policy.ex
@@ -0,0 +1,97 @@
+# 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.StealEmojiPolicy do
+ require Logger
+
+ alias Pleroma.Config
+
+ @moduledoc "Detect new emojis by their shortcode and steals them"
+ @behaviour Pleroma.Web.ActivityPub.MRF
+
+ defp remote_host?(host), do: host != Config.get([Pleroma.Web.Endpoint, :url, :host])
+
+ defp accept_host?(host), do: host in Config.get([:mrf_steal_emoji, :hosts], [])
+
+ defp steal_emoji({shortcode, url}) do
+ url = Pleroma.Web.MediaProxy.url(url)
+ {:ok, response} = Pleroma.HTTP.get(url)
+ size_limit = Config.get([:mrf_steal_emoji, :size_limit], 50_000)
+
+ if byte_size(response.body) <= size_limit do
+ emoji_dir_path =
+ Config.get(
+ [:mrf_steal_emoji, :path],
+ Path.join(Config.get([:instance, :static_dir]), "emoji/stolen")
+ )
+
+ extension =
+ url
+ |> URI.parse()
+ |> Map.get(:path)
+ |> Path.basename()
+ |> Path.extname()
+
+ file_path = Path.join([emoji_dir_path, shortcode <> (extension || ".png")])
+
+ try do
+ :ok = File.write(file_path, response.body)
+
+ shortcode
+ rescue
+ e ->
+ Logger.warn("MRF.StealEmojiPolicy: Failed to write to #{file_path}: #{inspect(e)}")
+ nil
+ end
+ else
+ Logger.debug(
+ "MRF.StealEmojiPolicy: :#{shortcode}: at #{url} (#{byte_size(response.body)} B) over size limit (#{
+ size_limit
+ } B)"
+ )
+
+ nil
+ end
+ rescue
+ e ->
+ Logger.warn("MRF.StealEmojiPolicy: Failed to fetch #{url}: #{inspect(e)}")
+ nil
+ end
+
+ @impl true
+ def filter(%{"object" => %{"emoji" => foreign_emojis, "actor" => actor}} = message) do
+ host = URI.parse(actor).host
+
+ if remote_host?(host) and accept_host?(host) do
+ installed_emoji = Pleroma.Emoji.get_all() |> Enum.map(fn {k, _} -> k end)
+
+ new_emojis =
+ foreign_emojis
+ |> Enum.filter(fn {shortcode, _url} -> shortcode not in installed_emoji end)
+ |> Enum.filter(fn {shortcode, _url} ->
+ reject_emoji? =
+ Config.get([:mrf_steal_emoji, :rejected_shortcodes], [])
+ |> Enum.find(false, fn regex -> String.match?(shortcode, regex) end)
+
+ !reject_emoji?
+ end)
+ |> Enum.map(&steal_emoji(&1))
+ |> Enum.filter(& &1)
+
+ if !Enum.empty?(new_emojis) do
+ Logger.info("Stole new emojis: #{inspect(new_emojis)}")
+ Pleroma.Emoji.reload()
+ end
+ end
+
+ {:ok, message}
+ end
+
+ def filter(message), do: {:ok, message}
+
+ @impl true
+ def describe do
+ {:ok, %{}}
+ end
+end