1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
# 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
|
