Golang：处理二进制数据

Question

I have application client(javascript)-server(golang) and the connection between them are all over websocket. I'm planing using binary messages and i want to create my own protocol for messaging like in this page protocol .

I'm already figure it out in javascript by using DataView but not in golang. Event the primitive data type are similar like they have int8, uint8, int16, uint16 etc, i can't figure it out.

This is the message frame:

1      Uint8      opcode
2      Uint16     msg

This is the example of javascript code handling the incoming message form websocket with message frame above:

websocket.onmessage = function(evt) {
    var data = new DataView(evt.data);
    var opcode = data.getUint8(0);
    var msg = data.getUint16(1);
}

Can you show me how to do it in golang? i'm using gorilla websocket . I know that read message are in []byte , but i don't know how to slice it like javascript does with DataView.

Thanks

Answer 1

For the uint16 you'll need the binary package. Double-check if LittleEndian is what you want.

package main

import (
    "encoding/binary"
)

func main() {
    a := []byte("yak")

    /* opcode  */ _ = uint8(a[0])
    /* message */ _ = binary.LittleEndian.Uint16(a[1:3])
}

https://play.golang.org/p/HRu7C5h2a5