GeezerVison

Go provides built-in support for base64 encoding/decoding.

package main

This syntax imports the encoding/base64 package with the b64 name instead of the default base64. It’ll save us some space below.

import (
    b64 "encoding/base64"
    "fmt"
)

func main() {

Here’s the string we’ll encode/decode.

    data := "abc123!?$*&()'-=@~"

Go supports both standard and URL-compatible base64. Here’s how to encode using the standard encoder. The encoder requires a []byte so we convert our string to that type.

    sEnc := b64.StdEncoding.EncodeToString([]byte(data))
    fmt.Println(sEnc)

Decoding may return an error, which you can check if you don’t already know the input to be well-formed.

    sDec, _ := b64.StdEncoding.DecodeString(sEnc)
    fmt.Println(string(sDec))
    fmt.Println()

This encodes/decodes using a URL-compatible base64 format.

    uEnc := b64.URLEncoding.EncodeToString([]byte(data))
    fmt.Println(uEnc)
    uDec, _ := b64.URLEncoding.DecodeString(uEnc)
    fmt.Println(string(uDec))
}

The string encodes to slightly different values with the standard and URL base64 encoders (trailing + vs -) but they both decode to the original string as desired.

$ go run base64-encoding.go
YWJjMTIzIT8kKiYoKSctPUB+
abc123!?$*&()'-=@~

YWJjMTIzIT8kKiYoKSctPUB-
abc123!?$*&()'-=@~