53 lines
1.8 KiB
Elixir
53 lines
1.8 KiB
Elixir
# Pleroma: A lightweight social networking server
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# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
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# SPDX-License-Identifier: AGPL-3.0-only
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defmodule Pleroma.Upload.Filter.Exiftool.ReadDescription do
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@moduledoc """
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Gets a valid description from the related EXIF tags and provides them in the response if no description is provided yet.
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It will first check ImageDescription, when that doesn't probide a valid description, it will check iptc:Caption-Abstract.
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A valid description means the fields are filled in and not too long (see `:instance, :description_limit`).
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"""
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@behaviour Pleroma.Upload.Filter
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@spec filter(Pleroma.Upload.t()) :: {:ok, any()} | {:error, String.t()}
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def filter(%Pleroma.Upload{description: description})
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when is_binary(description),
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do: {:ok, :noop}
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def filter(%Pleroma.Upload{tempfile: file} = upload),
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do: {:ok, :filtered, upload |> Map.put(:description, read_description_from_exif_data(file))}
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def filter(_, _), do: {:ok, :noop}
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defp read_description_from_exif_data(file) do
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nil
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|> read_when_empty(file, "-ImageDescription")
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|> read_when_empty(file, "-iptc:Caption-Abstract")
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end
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defp read_when_empty(current_description, _, _) when is_binary(current_description),
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do: current_description
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defp read_when_empty(_, file, tag) do
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try do
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{tag_content, 0} =
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System.cmd("exiftool", ["-b", "-s3", tag, file],
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stderr_to_stdout: false,
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parallelism: true
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)
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tag_content = String.trim(tag_content)
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if tag_content != "" and
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String.length(tag_content) <=
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Pleroma.Config.get([:instance, :description_limit]),
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do: tag_content,
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else: nil
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rescue
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_ in ErlangError -> nil
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end
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end
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end
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