Image Exchange Format

import magic
print(magic.from_file('document.ief', mime=True)) # Will typically resolve to 'image/tiff' due to the shared header

const FileType = require('file-type');
const type = await FileType.fromFile('document.ief');
console.log(type?.mime); // Parsers will likely return 'image/tiff'

import "net/http"
// HTTP detection will fall back to standard TIFF
if bytes.HasPrefix(buf, []byte{0x49, 0x49, 0x2A, 0x00}) || bytes.HasPrefix(buf, []byte{0x4D, 0x4D, 0x00, 0x2A}) {
    fmt.Println("image/tiff (or image/ief)")
}

$mime = mime_content_type('document.ief');
echo $mime; // Most likely outputs 'image/tiff'