92 lines
2.4 KiB
Elixir
92 lines
2.4 KiB
Elixir
# Pleroma: A lightweight social networking server
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# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
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# SPDX-License-Identifier: AGPL-3.0-only
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defmodule Pleroma.Helpers.MediaHelper do
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@moduledoc """
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Handles common media-related operations.
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"""
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@tmp_base "/tmp/pleroma-media_preview-pipe"
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def image_resize(url, options) do
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with executable when is_binary(executable) <- System.find_executable("convert"),
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{:ok, args} <- prepare_image_resize_args(options),
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url = Pleroma.Web.MediaProxy.url(url),
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{:ok, env} <- Pleroma.HTTP.get(url),
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{:ok, fifo_path} <- mkfifo()
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do
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run_fifo(fifo_path, env, executable, args)
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else
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nil -> {:error, {:convert, :command_not_found}}
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{:error, _} = error -> error
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end
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end
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defp prepare_image_resize_args(%{max_width: max_width, max_height: max_height} = options) do
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quality = options[:quality] || 85
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resize = Enum.join([max_width, "x", max_height, ">"])
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args = [
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"-interlace", "Plane",
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"-resize", resize,
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"-quality", to_string(quality),
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"jpg:-"
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]
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{:ok, args}
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end
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defp prepare_image_resize_args(_), do: {:error, :missing_options}
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defp run_fifo(fifo_path, env, executable, args) do
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args = List.flatten([fifo_path, args])
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pid = Port.open({:spawn_executable, executable}, [:use_stdio, :stream, :exit_status, :binary, args: args])
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fifo = Port.open(to_charlist(fifo_path), [:eof, :binary, :stream, :out])
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true = Port.command(fifo, env.body)
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:erlang.port_close(fifo)
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loop_recv(pid)
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after
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File.rm(fifo_path)
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end
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defp mkfifo() do
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path = "#{@tmp_base}#{to_charlist(:erlang.phash2(self()))}"
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case System.cmd("mkfifo", [path]) do
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{_, 0} ->
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spawn(fifo_guard(path))
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{:ok, path}
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{_, err} ->
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{:error, {:fifo_failed, err}}
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end
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end
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defp fifo_guard(path) do
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pid = self()
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fn() ->
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ref = Process.monitor(pid)
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receive do
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{:DOWN, ^ref, :process, ^pid, _} ->
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File.rm(path)
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end
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end
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end
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defp loop_recv(pid) do
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loop_recv(pid, <<>>)
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end
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defp loop_recv(pid, acc) do
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receive do
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{^pid, {:data, data}} ->
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loop_recv(pid, acc <> data)
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{^pid, {:exit_status, 0}} ->
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{:ok, acc}
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{^pid, {:exit_status, status}} ->
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{:error, status}
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after
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5000 ->
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:erlang.port_close(pid)
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{:error, :timeout}
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end
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end
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end
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