Mark Felder
0ac010ba3f
This is for streaming media to ffmpeg thumbnailer. The existing implementation relies on undocumented behavior.
Erlang open_port/2 does not officially support passing a string of a file path for opening. The specs clearly state you are to provide one of the following for open_port/2:
{spawn, Command :: string() | binary()} |
{spawn_driver, Command :: string() | binary()} |
{spawn_executable, FileName :: file:name_all()} |
{fd, In :: integer() >= 0, Out :: integer() >= 0}
Our method technically works but is strongly discouraged as it can block the scheduler and dialyzer throws errors as it recognizes we're breaking the contract and some of the functions we wrote may never return.
This is indirectly covered by the Erlang FAQ section "9.12 Why can't I open devices (e.g. a serial port) like normal files?"
https://www.erlang.org/faq/problems#idm1127
71 lines
1.8 KiB
Elixir
71 lines
1.8 KiB
Elixir
# Pleroma: A lightweight social networking server
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# Copyright © 2017-2022 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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alias Pleroma.HTTP
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alias Vix.Vips.Operation
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require Logger
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def missing_dependencies do
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Enum.reduce([ffmpeg: "ffmpeg"], [], fn {sym, executable}, acc ->
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if Pleroma.Utils.command_available?(executable) do
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acc
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else
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[sym | acc]
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end
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end)
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end
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def image_resize(url, options) do
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with {:ok, env} <- HTTP.get(url, [], pool: :media),
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{:ok, resized} <-
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Operation.thumbnail_buffer(env.body, options.max_width,
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height: options.max_height,
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size: :VIPS_SIZE_DOWN
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) do
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if options[:format] == "png" do
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Operation.pngsave_buffer(resized, Q: options[:quality])
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else
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Operation.jpegsave_buffer(resized, Q: options[:quality], interlace: true)
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end
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else
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{:error, _} = error -> error
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end
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end
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# Note: video thumbnail is intentionally not resized (always has original dimensions)
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def video_framegrab(url) do
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with executable when is_binary(executable) <- System.find_executable("ffmpeg"),
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{:ok, env} <- HTTP.get(url, [], pool: :media),
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{:ok, pid} <- StringIO.open(env.body) do
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body_stream = IO.binstream(pid, 1)
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Exile.stream!(
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[
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executable,
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"-i",
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"pipe:0",
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"-vframes",
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"1",
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"-f",
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"mjpeg",
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"pipe:1"
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],
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input: body_stream,
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ignore_epipe: true,
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stderr: :disable
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)
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|> Enum.into(<<>>)
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else
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nil -> {:error, {:ffmpeg, :command_not_found}}
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{:error, _} = error -> error
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end
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end
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end
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