media_type_of

Finds the media type of an image from its first bytes (its magic number), whatever its name says: PNG, JPEG, GIF, WebP, AVIF and SVG. SVG has no magic number, so it is recognized as text whose first element is <svg, possibly after a byte order mark, whitespace, an XML declaration, comments or a doctype.

Import

use helpers4::bytes::media_type_of;

Cargo feature bytes (enabled by default). To compile only this module:

cargo add helpers4 --no-default-features --features bytes

or in Cargo.toml:

[dependencies]
helpers4 = { version = "0.0.11", default-features = false, features = ["bytes"] }

Signature

pub fn media_type_of(bytes: &[u8]) -> Option<&'static str>

Parameters

Parameter	Type	Description
bytes	&[u8]	The start of the file: 512 bytes are enough for every type but a long SVG prolog.

Returns

Option<&'static str> — The media type ("image/png", …), or None when it is none of these.

Examples

use helpers4::bytes::media_type_of;

assert_eq!(media_type_of(&[0x89, b'P', b'N', b'G', 0x0d, 0x0a, 0x1a, 0x0a]), Some("image/png"));
assert_eq!(media_type_of(b"<svg xmlns='http://www.w3.org/2000/svg'/>"), Some("image/svg+xml"));
assert_eq!(media_type_of(b"hello"), None);

Source

src/bytes/media_type_of.rs