git.squeep.com Git - akkoma/blob - lib/pleroma/helpers/media_helper.ex

   1 # Pleroma: A lightweight social networking server
   2 # Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
   3 # SPDX-License-Identifier: AGPL-3.0-only
   4
   5 defmodule Pleroma.Helpers.MediaHelper do
   6   @moduledoc """
   7   Handles common media-related operations.
   8   """
   9
  10   alias Pleroma.HTTP
  11
  12   require Logger
  13
  14   def missing_dependencies do
  15     Enum.reduce([imagemagick: "convert", ffmpeg: "ffmpeg"], [], fn {sym, executable}, acc ->
  16       if Pleroma.Utils.command_available?(executable) do
  17         acc
  18       else
  19         [sym | acc]
  20       end
  21     end)
  22   end
  23
  24   def image_resize(url, options) do
  25     with executable when is_binary(executable) <- System.find_executable("convert"),
  26          {:ok, args} <- prepare_image_resize_args(options),
  27          {:ok, env} <- HTTP.get(url, [], []),
  28          {:ok, fifo_path} <- mkfifo() do
  29       args = List.flatten([fifo_path, args])
  30       run_fifo(fifo_path, env, executable, args)
  31     else
  32       nil -> {:error, {:convert, :command_not_found}}
  33       {:error, _} = error -> error
  34     end
  35   end
  36
  37   defp prepare_image_resize_args(
  38          %{max_width: max_width, max_height: max_height, format: "png"} = options
  39        ) do
  40     quality = options[:quality] || 85
  41     resize = Enum.join([max_width, "x", max_height, ">"])
  42
  43     args = [
  44       "-resize",
  45       resize,
  46       "-quality",
  47       to_string(quality),
  48       "png:-"
  49     ]
  50
  51     {:ok, args}
  52   end
  53
  54   defp prepare_image_resize_args(%{max_width: max_width, max_height: max_height} = options) do
  55     quality = options[:quality] || 85
  56     resize = Enum.join([max_width, "x", max_height, ">"])
  57
  58     args = [
  59       "-interlace",
  60       "Plane",
  61       "-resize",
  62       resize,
  63       "-quality",
  64       to_string(quality),
  65       "jpg:-"
  66     ]
  67
  68     {:ok, args}
  69   end
  70
  71   defp prepare_image_resize_args(_), do: {:error, :missing_options}
  72
  73   # Note: video thumbnail is intentionally not resized (always has original dimensions)
  74   def video_framegrab(url) do
  75     with executable when is_binary(executable) <- System.find_executable("ffmpeg"),
  76          {:ok, env} <- HTTP.get(url, [], []),
  77          {:ok, fifo_path} <- mkfifo(),
  78          args = [
  79            "-y",
  80            "-i",
  81            fifo_path,
  82            "-vframes",
  83            "1",
  84            "-f",
  85            "mjpeg",
  86            "-loglevel",
  87            "error",
  88            "-"
  89          ] do
  90       run_fifo(fifo_path, env, executable, args)
  91     else
  92       nil -> {:error, {:ffmpeg, :command_not_found}}
  93       {:error, _} = error -> error
  94     end
  95   end
  96
  97   defp run_fifo(fifo_path, env, executable, args) do
  98     pid =
  99       Port.open({:spawn_executable, executable}, [
 100         :use_stdio,
 101         :stream,
 102         :exit_status,
 103         :binary,
 104         args: args
 105       ])
 106
 107     fifo = File.open!(fifo_path, [:append, :binary])
 108     fix = Pleroma.Helpers.QtFastStart.fix(env.body)
 109     IO.binwrite(fifo, fix)
 110     File.close(fifo)
 111     loop_recv(pid)
 112   after
 113     File.rm(fifo_path)
 114   end
 115
 116   defp mkfifo do
 117     path = Path.join(System.tmp_dir!(), "pleroma-media-preview-pipe-#{Ecto.UUID.generate()}")
 118
 119     case System.cmd("mkfifo", [path]) do
 120       {_, 0} ->
 121         spawn(fifo_guard(path))
 122         {:ok, path}
 123
 124       {_, err} ->
 125         {:error, {:fifo_failed, err}}
 126     end
 127   end
 128
 129   defp fifo_guard(path) do
 130     pid = self()
 131
 132     fn ->
 133       ref = Process.monitor(pid)
 134
 135       receive do
 136         {:DOWN, ^ref, :process, ^pid, _} ->
 137           File.rm(path)
 138       end
 139     end
 140   end
 141
 142   defp loop_recv(pid) do
 143     loop_recv(pid, <<>>)
 144   end
 145
 146   defp loop_recv(pid, acc) do
 147     receive do
 148       {^pid, {:data, data}} ->
 149         loop_recv(pid, acc <> data)
 150
 151       {^pid, {:exit_status, 0}} ->
 152         {:ok, acc}
 153
 154       {^pid, {:exit_status, status}} ->
 155         {:error, status}
 156     after
 157       5000 ->
 158         :erlang.port_close(pid)
 159         {:error, :timeout}
 160     end
 161   end
 162 end