Is there a way in go to convert a []byte slice to an io.Reader?

Question

I have just started with go and was wondering, if it is possible to convert an []byte slice to an io.Reader. The Otherway around is possible as shown in ioutil.ReadAll.
If not is it possible to use code.google.com/p/go.net/html.Tokenizer somehow with a byte slice?

score 12 · Accepted Answer · answered Aug 26 '14 at 01:42

12

Yes: bytes.NewBuffer

io.Reader Example:

http://play.golang.org/p/P0VbE8UFpC

package main

import (
    "bytes"
    "encoding/base64"
    "io"
    "os"
)

func main() {
    // A Buffer can turn a string or a []byte into an io.Reader.
    buf := bytes.NewBuffer([]byte("R29waGVycyBydWxlIQ=="))
    dec := base64.NewDecoder(base64.StdEncoding, buf)
    io.Copy(os.Stdout, dec)
}

answered Aug 26 '14 at 01:42

fabrizioM

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2

What's different from `bytes.NewReader`? – Fred Hors Jul 03 '20 at 08:46
2

@FredHors I know it's been a while but I was also curious about this, so I looked into the source code. [Taken from a comment in the source code](https://github.com/golang/go/blob/master/src/bytes/reader.go#L16) `// Unlike a Buffer, a Reader is read-only and supports seeking.`. I suppose the question should be "what's your use case?" – Matt Oestreich Sep 27 '20 at 23:11

score 8 · Answer 2 · edited Nov 16 '18 at 18:53

8

You can use the NewReader in the bytes package:

in := bytes.NewReader(b []byte)

https://golang.org/pkg/bytes/#NewReader

edited Nov 16 '18 at 18:53

Fox32

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answered Jul 06 '17 at 09:38

Eurospoofer

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1

What's different from `bytes.NewBuffer`? – Fred Hors Jul 03 '20 at 08:46
1

(putting this here, too) I know it's been a while but I was also curious about this, so I looked into the source code. [Taken from a comment in the source code](https://github.com/golang/go/blob/master/src/bytes/reader.go#L16) // Unlike a Buffer, a Reader is read-only and supports seeking.. I suppose the question should be "what's your use case?" – Matt Oestreich Sep 27 '20 at 23:12

Is there a way in go to convert a []byte slice to an io.Reader?

2 Answers2