magicmime

magicmime is a Go package which allows you to discover a file's mimetype by looking for magic numbers in its content. It could be used as a supplementary for Go's mime package which only interprets the file extension to detect mimetypes. Internally, it implements libmagic(3) bindings.

Tested on Linux and Mac OS X, should be working on BSD. You could be able to build and make it working with Cygwin on Windows.

Prerequisites

You might need to install devel packages for libmagic. On Debian, Ubuntu and CentOS, get libmagic-dev package from your package manager. On Mac OS X get libmagic via Homebrew: brew install libmagic. If you don't have the required dev packages, compilation will be terminated by an error saying magic.h cannot be found.

Usage

In order to start, go get this repository:

go get github.com/rakyll/magicmime

Example

package main

import (
	"fmt"

	"github.com/rakyll/magicmime"
)

func main() {
	mm, err := magicmime.New(magicmime.MAGIC_MIME_TYPE | magicmime.MAGIC_SYMLINK | magicmime.MAGIC_ERROR)
	if err != nil {
		panic(err)
	}

	filepath := "/bin/ls"

	mimetype, err := mm.TypeByFile(filepath)
	if err != nil {
		fmt.Printf("Something went wrong: %s", err)
		return
	}

	fmt.Printf("%s -> %s\n", filepath, mimetype)
}

API

https://godoc.org/github.com/rakyll/magicmime

Note for OS X (Brew) Users:

If you have installed libmagick with brew you have to edit flags in magicmime.go file:

.
.
.
// #cgo LDFLAGS: -lmagic -L/usr/local/lib
// #cgo CFLAGS: -I/usr/local/include
// #include <stdlib.h>
// #include <magic.h>
import "C"
.
.
.

License

Copyright 2013 Google Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.