mimemagic =========

Powerful and versatile MIME sniffing package using pre-compiled glob patterns, magic number signatures, xml document namespaces, and tree magic for mounted volumes, generated from the XDG shared-mime-info database.

License

The generated code in magicsigs.go, globs.go, treemagicsigs.go, namespaces.go and mediatypes.go makes this a derivative work of shared-mime-info, and therefore falls under the GPL-2.0-or-later license. See the discussion.

For an MIT licensed branch with the generated code removed, please see this. Providing a hypothetical permissively licensed freedesktop.org.xml file for parsing is still required, to redistribute the compiled executable with that license, however.

Features

• All in native go, no outside dependencies/C library bindings
• 1003 MIME types, with a description, an acronym (where available), common aliases, extensions, icons, and

• 493 magic signature tests (comprising of 1147 individual patterns), featuring range searches and bit masks, as per

• 1099 glob patterns, for filename-based matching
• 11 Tree Magic signatures and 28 XML namespace/local name pairs, offered for completeness' sake.
• Included is the xml file parser to generate your own MIME definitions
• Also included is a CLI based on this library that is fully featured and blazing-fast, beating the native 'file'

• Cross-platform support

Installation

The library:

go get github.com/zRedShift/mimemagic/v2

go get github.com/zRedShift/mimemagic/v2/cmd/mimemagic

API

See the Godoc reference, and cmd/mimemagic for an example implementation.

Usage

The library:

package main

import ( 	"fmt" 	"github.com/zRedShift/mimemagic/v2" 	"strings" )
func main() { 	// Ignoring Read errors that might arise 	mimeType, _ := mimemagic.MatchFilePath("sample.svgz", -1)
// image/svg+xml-compressed 	fmt.Println(mimeType.MediaType())
// compressed SVG image 	fmt.Println(mimeType.Comment)
// SVG (Scalable Vector Graphics) 	fmt.Printf("%s (%s)\n", mimeType.Acronym, mimeType.ExpandedAcronym)
// application/gzip 	fmt.Println(strings.Join(mimeType.SubClassOf, ", "))
// .svgz 	fmt.Println(strings.Join(mimeType.Extensions, ", "))
// This is an image. 	switch mimeType.Media { 	case "image": 		fmt.Println("This is an image.") 	case "video": 		fmt.Println("This is a video file.") 	case "audio": 		fmt.Println("This is an audio file.") 	case "application": 		fmt.Println("This is an application.") 	default: 		fmt.Printf("This is a(n) %s.", mimeType.Media) 	}
// true 	fmt.Println(mimeType.IsExtension(".svgz")) }

Usage: mimemagic [options] <file> ... Determines the MIME type of the given file(s).

Options:   -c    Determine the MIME type of the file(s) using only its content.   -f    Determine the MIME type of the file(s) using only the file name. Does         not check for the file's existence. The -c          flag takes precedence.   -i    Output the MIME type in a human readable format.   -l int         The number of bytes from the beginning of the file mimemagic will         examine. Reads the entire file if set to a negative value. By default         mimemagic will only read the first 512 from stdin, however setting this         flag to a non-default negative value will override this. (default -1)   -t    Determine the MIME type of the directory/mounted volume using tree         magic. Can't be used in conjunction with with -c, -f or -x.   -x    Determine the MIME type of the xml file(s) using the local names and         namespaces within. Can't be used in conjunction with -c, -f or -t.
Arguments:   file         The file(s) to test. '-' to read from stdin. If '-' is set, all other         inputs will be ignored.
Examples:   $ mimemagic -c sample.svgz     	application/gzip   $ mimemagic .svg     	Olympicringswithtransparentrims.svg: image/svg+xml     	Piano.svg.png: image/png     	RAID_5.svg: image/svg+xml     	sample.svgz: image/svg+xml-compressed   $ cat /dev/urandom | mimemagic -     	application/octet-stream   $ ls software; mimemagic -i -t software/     	autorun     	UNIX software

Benchmarks

See Benchmarks. For Match(), the average across over 400 completely different files (representing a unique MIME type each) is 13 ± 7 μs/op. For MatchGlob() it's 900 ± 200 ns/op, and for 12 ± 7 μs/op MatchMagic().