infer2

Small crate to infer file and MIME type by checking the magic number signature.

Adaptation of filetype Go package ported to Rust.

infer2 is a maintained fork of the original infer crate. New releases use the crate name infer2, while keeping the public API compatible for common use cases, so migrating is usually limited to renaming the dependency and imports.

Does not require magic file database (i.e. /etc/magic).

Features

Supports a wide range of file types
Provides file extension and MIME type
File discovery by extension or MIME type
File discovery by class (image, video, audio...)
Supports custom new types and matchers

Installation

When using the republished crate, add infer2 to your Cargo.toml like so:

[dependencies]
infer2 = "0.21" # or the latest published version

If you are not using the custom matcher or the file type from file path functionality you can make this crate even lighter by importing it with no default features, like so:

[dependencies]
infer2 = { version = "0.21", default-features = false } # or the latest published version

no_std and no_alloc support

This crate supports no_std and no_alloc environments. std support is enabled by default, but you can disable it by importing the crate with no default features, making it depend only on the Rust core Library.

alloc has to be enabled to be able to use custom file matchers.

std has to be enabled to be able to get the file type from a file given the file path.

Examples

Most operations can be done via top level functions, but they are also available through the Infer struct, which must be used when dealing custom matchers.

Get the type of a buffer

let buf = [0xFF, 0xD8, 0xFF, 0xAA];
let kind = infer2::get(&buf).expect("file type is known");

assert_eq!(kind.mime_type(), "image/jpeg");
assert_eq!(kind.extension(), "jpg");

Check file type by path

let kind = infer2::get_from_path("testdata/sample.jpg")
    .expect("file read successfully")
    .expect("file type is known");

assert_eq!(kind.mime_type(), "image/jpeg");
assert_eq!(kind.extension(), "jpg");

Check for specific type

let buf = [0xFF, 0xD8, 0xFF, 0xAA];
assert!(infer2::image::is_jpeg(&buf));

Check for specific type class

let buf = [0xFF, 0xD8, 0xFF, 0xAA];
assert!(infer2::is_image(&buf));

Adds a custom file type matcher

fn custom_matcher(buf: &[u8]) -> bool {
    return buf.len() >= 3 && buf[0] == 0x10 && buf[1] == 0x11 && buf[2] == 0x12;
}

let mut info = infer2::Infer::new();
info.add("custom/foo", "foo", custom_matcher);

let buf = [0x10, 0x11, 0x12, 0x13];
let kind = info.get(&buf).expect("file type is known");

assert_eq!(kind.mime_type(), "custom/foo");
assert_eq!(kind.extension(), "foo");

Supported types

Image

jpg - image/jpeg
png - image/png
gif - image/gif
webp - image/webp
cr2 - image/x-canon-cr2
tif - image/tiff
bmp - image/bmp
heif - image/heif
avif - image/avif
jxr - image/vnd.ms-photo
psd - image/vnd.adobe.photoshop
ico - image/vnd.microsoft.icon
ora - image/openraster
djvu - image/vnd.djvu

Video

mp4 - video/mp4
m4v - video/x-m4v
mkv - video/x-matroska
webm - video/webm
mov - video/quicktime
avi - video/x-msvideo
wmv - video/x-ms-wmv
mpg - video/mpeg
flv - video/x-flv

Audio

mid - audio/midi
mp3 - audio/mpeg
m4a - audio/m4a
ogg - audio/ogg
flac - audio/x-flac
wav - audio/x-wav
amr - audio/amr
aac - audio/aac
aiff - audio/x-aiff
dsf - audio/x-dsf
ape - audio/x-ape

Book

epub - application/epub+zip
mobi - application/x-mobipocket-ebook

Documents

doc - application/msword
docx - application/vnd.openxmlformats-officedocument.wordprocessingml.document
xls - application/vnd.ms-excel
xlsx - application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
ppt - application/vnd.ms-powerpoint
pptx - application/vnd.openxmlformats-officedocument.presentationml.presentation
odt - application/vnd.oasis.opendocument.text
ods - application/vnd.oasis.opendocument.spreadsheet
odp - application/vnd.oasis.opendocument.presentation

Font

woff - application/font-woff
woff2 - application/font-woff
ttf - application/font-sfnt
otf - application/font-sfnt

Application

wasm - application/wasm
exe - application/vnd.microsoft.portable-executable
dll - application/vnd.microsoft.portable-executable
elf - application/x-executable
bc - application/llvm
mach - application/x-mach-binary
class - application/java
dex - application/vnd.android.dex
dey - application/vnd.android.dey
der - application/x-x509-ca-cert
obj - application/x-executable
qcow2 - application/x-qemu-disk

Known Issues

exe and dll have the same magic number so it's not possible to tell which one just based on the binary data. exe is returned for all.

License

MIT

infer2 0.21.1