basic_auth.go

package main

import (
	"encoding/base64"
	"fmt"
)

type User struct {
	name, pass string
}

func (u User) Base64() string {
	return encode64(u.name + ":" + u.pass)
}

func encode64(s string) string {
	return base64.StdEncoding.EncodeToString([]byte(s))
}

func decode64(s string) (string, error) {
	data, err := base64.StdEncoding.DecodeString(s)

	// Check for error
	if err != nil {
		return "", err
	}

	return string(data), nil
}

func main() {
	var s string

	fmt.Println(User{name: "test_name"}.Base64())
	s, _ = decode64("dGVzdF9uYW1lOg==")
	fmt.Printf("%q\n", s)

	fmt.Println(User{name: "Aladdin", pass: "open sesame"}.Base64())
	s, _ = decode64("QWxhZGRpbjpvcGVuIHNlc2FtZQ==")
	fmt.Printf("%q\n", s)
}

Live code - http://play.golang.org/p/UD2TUfDgl6