# Pleroma: A lightweight social networking server # Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/> # SPDX-License-Identifier: AGPL-3.0-only defmodule Pleroma.MIME do @moduledoc """ Returns the mime-type of a binary and optionally a normalized file-name. """ @default "application/octet-stream" @read_bytes 35 @spec file_mime_type(String.t(), String.t()) :: {:ok, content_type :: String.t(), filename :: String.t()} | {:error, any()} | :error def file_mime_type(path, filename) do with {:ok, content_type} <- file_mime_type(path), filename <- fix_extension(filename, content_type) do {:ok, content_type, filename} end end @spec file_mime_type(String.t()) :: {:ok, String.t()} | {:error, any()} | :error def file_mime_type(filename) do File.open(filename, [:read], fn f -> check_mime_type(IO.binread(f, @read_bytes)) end) end def bin_mime_type(binary, filename) do with {:ok, content_type} <- bin_mime_type(binary), filename <- fix_extension(filename, content_type) do {:ok, content_type, filename} end end @spec bin_mime_type(binary()) :: {:ok, String.t()} | :error def bin_mime_type(<<head::binary-size(@read_bytes), _::binary>>) do {:ok, check_mime_type(head)} end def bin_mime_type(_), do: :error def mime_type(<<_::binary>>), do: {:ok, @default} defp fix_extension(filename, content_type) do parts = String.split(filename, ".") new_filename = if length(parts) > 1 do Enum.drop(parts, -1) |> Enum.join(".") else Enum.join(parts) end cond do content_type == "application/octet-stream" -> filename ext = List.first(MIME.extensions(content_type)) -> new_filename <> "." <> ext true -> Enum.join([new_filename, String.split(content_type, "/") |> List.last()], ".") end end defp check_mime_type(<<0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, _::binary>>) do "image/png" end defp check_mime_type(<<0x47, 0x49, 0x46, 0x38, _, 0x61, _::binary>>) do "image/gif" end defp check_mime_type(<<0xFF, 0xD8, 0xFF, _::binary>>) do "image/jpeg" end defp check_mime_type(<<0x1A, 0x45, 0xDF, 0xA3, _::binary>>) do "video/webm" end defp check_mime_type(<<0x00, 0x00, 0x00, _, 0x66, 0x74, 0x79, 0x70, _::binary>>) do "video/mp4" end defp check_mime_type(<<0x49, 0x44, 0x33, _::binary>>) do "audio/mpeg" end defp check_mime_type(<<255, 251, _, 68, 0, 0, 0, 0, _::binary>>) do "audio/mpeg" end defp check_mime_type( <<0x4F, 0x67, 0x67, 0x53, 0x00, 0x02, 0x00, 0x00, _::size(160), 0x80, 0x74, 0x68, 0x65, 0x6F, 0x72, 0x61, _::binary>> ) do "video/ogg" end defp check_mime_type(<<0x4F, 0x67, 0x67, 0x53, 0x00, 0x02, 0x00, 0x00, _::binary>>) do "audio/ogg" end defp check_mime_type(<<"RIFF", _::binary-size(4), "WAVE", _::binary>>) do "audio/wav" end defp check_mime_type(<<"RIFF", _::binary-size(4), "WEBP", _::binary>>) do "image/webp" end defp check_mime_type(<<"RIFF", _::binary-size(4), "AVI.", _::binary>>) do "video/avi" end defp check_mime_type(_) do @default end end