emoji-stealer-mrf/steal_emoji_policy.ex

# SPDX-License-Identifier: AGPL-3.0-only

defmodule Pleroma.Web.ActivityPub.MRF.StealEmojiPolicy do
  require Logger
  @moduledoc "Detect new emoji and steal them"
  @behaviour Pleroma.Web.ActivityPub.MRF

  defp has_emojo(installed_emoji, str) do
    result = for emojo <- installed_emoji, elem(emojo, 0) == str, do: true
    length(result) == 1
  end

  defp is_remote(host) do
    my_host = Pleroma.Config.get([Pleroma.Web.Endpoint, :url, :host])
    my_host != host
  end

  # if whitelist is not defined, everything is "whitelisted"
  defp is_whitelisted(domain) do
    whitelist = Pleroma.Config.get([:emoji_stealer, :whitelist])

    whitelist == nil || Enum.member?(whitelist, domain)
  end

  @impl true
  def filter(%{"object" => %{"emoji" => foreign_emoji, "actor" => actor}} = object) do
    host = URI.parse(actor).host

    if is_remote(host) && is_whitelisted(host) do
      num_foreign_emoji = Kernel.map_size(foreign_emoji)

      if num_foreign_emoji > 0 do
        Logger.debug("#{num_foreign_emoji} EMOJI TO PROCESS")
        installed_emoji = Pleroma.Emoji.get_all()

        new_files =
          for {emojo_shortcode, emojo_url} <- foreign_emoji,
              !has_emojo(installed_emoji, emojo_shortcode) do
            Logger.debug("HANDLING EMOJO #{emojo_shortcode} #{emojo_url}")

            cond do
              !String.match?(emojo_shortcode, ~r/^[[:word:]]+$/) ->
                Logger.error("BAD EMOJO SHORTCODE: #{emojo_shortcode}")

              String.starts_with?(emojo_url, "https://") ->
                try do
                  remote_emojo = HTTPoison.get!(emojo_url)

                  if remote_emojo.status_code == 200 do
                    Logger.debug("got remote emoji")
                    emoji_dir_path = Path.join(Pleroma.Config.get!([:instance, :static_dir]), "emoji/stolen")

                    emojo_uri = URI.parse(emojo_url)
                    extension = Path.extname(Path.basename(emojo_uri.path))
                    filename = emojo_shortcode <> extension

                    new_file = Path.join([emoji_dir_path, filename])

                    {:ok, file} = File.open(new_file, [:write])
                    IO.binwrite(file, remote_emojo.body)
                    File.close(file)
                    Logger.debug("SAVED EMOJO")
                    new_file
                  end
                rescue
                  e in RuntimeError -> Logger.error("FAILED TO QUERY REMOTE EMOJO #{emojo_url} #{e}")
                end

              true ->
                Logger.error("EMOJO COND FAIL #{emojo_shortcode} #{emojo_url}")
            end
            

          end

        Logger.debug("EMOJI FILES: #{inspect(new_files)}")

        if length(new_files) > 0 do
          Logger.debug("RELOADING EMOJI")
          Pleroma.Emoji.reload()
        else
          Logger.debug("NO EMOJI TO LOAD")
        end
      end
    end

    {:ok, object}
  end

  @impl true
  def filter(object) do
    {:ok, object}
  end

  @impl true
  def describe, do: {:ok, %{}}
end