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   1 # Pleroma: A lightweight social networking server
   2 # Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
   3 # SPDX-License-Identifier: AGPL-3.0-only
   4
   5 defmodule Pleroma.Upload.Filter.Exiftool do
   6   @moduledoc """
   7   Strips GPS related EXIF tags and overwrites the file in place.
   8   Also strips or replaces filesystem metadata e.g., timestamps.
   9   """
  10   @behaviour Pleroma.Upload.Filter
  11
  12   @spec filter(Pleroma.Upload.t()) :: {:ok, any()} | {:error, String.t()}
  13   def filter(%Pleroma.Upload{name: file, tempfile: path, content_type: "image" <> _}) do
  14     # webp is not compatible with exiftool at this time
  15     if Regex.match?(~r/\.(webp)$/i, file) do
  16       {:ok, :noop}
  17     else
  18       strip_exif(path)
  19     end
  20   end
  21
  22   def filter(_), do: {:ok, :noop}
  23
  24   defp strip_exif(path) do
  25     try do
  26       case System.cmd("exiftool", ["-overwrite_original", "-gps:all=", path], parallelism: true) do
  27         {_response, 0} -> {:ok, :filtered}
  28         {error, 1} -> {:error, error}
  29       end
  30     rescue
  31       _e in ErlangError ->
  32         {:error, "exiftool command not found"}
  33     end
  34   end
  35 end