Base64 Encoding

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