Base64 Encoding

Syntax#

func (enc *base64.Encoding) Encode(dst, src []byte)
func (enc *base64.Encoding) Decode(dst, src []byte) (n int, err error)
func (enc *base64.Encoding) EncodeToString(src []byte) string
func (enc *base64.Encoding) DecodeString(s string) ([]byte, error)

Remarks#

The encoding/base64 package contains several built in encoders. Most of the examples in this document will use base64.StdEncoding, but any encoder (URLEncoding, RawStdEncodign, your own custom encoder, etc.) may be substituted.

Encoding

const foobar = `foo bar`
encoding := base64.StdEncoding
encodedFooBar := make([]byte, encoding.EncodedLen(len(foobar)))
encoding.Encode(encodedFooBar, []byte(foobar))
fmt.Printf("%s", encodedFooBar)
// Output: Zm9vIGJhcg==

Playground

Encoding to a String

str := base64.StdEncoding.EncodeToString([]byte(`foo bar`))
fmt.Println(str)
// Output: Zm9vIGJhcg==

Playground

Decoding

encoding := base64.StdEncoding
data := []byte(`Zm9vIGJhcg==`)
decoded := make([]byte, encoding.DecodedLen(len(data)))
n, err := encoding.Decode(decoded, data)
if err != nil {
    log.Fatal(err)
}

// Because we don't know the length of the data that is encoded
// (only the max length), we need to trim the buffer to whatever
// the actual length of the decoded data was.
decoded = decoded[:n]

fmt.Printf("`%s`", decoded)
// Output: `foo bar`

Playground

Decoding a String

decoded, err := base64.StdEncoding.DecodeString(`biws`)
if err != nil {
    log.Fatal(err)
}

fmt.Printf("%s", decoded)
// Output: n,,

Playground