Golang中来自hex和readUInt16BE的Node.js缓冲区

Question

I have a code like this in nodejs:

// Create Buffer from hex representation
b = new Buffer('002400050200000000320000000003847209cd4450ff94ad8c0000000002c581000001d3', 'hex')

// Read with offset 0
b.readUInt16BE(0) // -> Out: 36

It reads a string which is an hex representation of data. When first two bytes are read readUInt16BE, an int (36) is obtained. That is the expected behavior.

I need to replicate this behavior using Go, but I have some troubles.

1) How to create a buffer from an string in hex format? 2) How to implement a readUInt16BE function in order to obtain (36) when first two bytes are read?

I can create a buffer with 00 24, but I need to use any string.

// Creates buffer [00 24]
v := make([]byte, 0, 2)
v = append(v, 0)
v = append(v, 24)
fmt.Println(v) // -> out: [0 24]

Finally, I am a little confused with function binary.BigEndian.Uint16, which is returning 24 instead 36.

x := binary.BigEndian.Uint16(v)
fmt.Println(x) // -> out: 24

Can you help me to understand this?

Answer 1

You are appending a decimal value of 24 to the buffer, when you should be appending the hexadecimal value 0x24:

v := make([]byte, 0, 2)
v = append(v, 0)
v = append(v, 0x24)
fmt.Println(v)

x := binary.BigEndian.Uint16(v)
fmt.Println(x)

Converting the the original Node.js code to Go would look something like the following:

import (
    "encoding/binary"
    "encoding/hex"
)

b, err := hex.DecodeString(`002400050200000000320000000003847209cd4450ff94ad8c0000000002c581000001d3`)
if err != nil {
    // TODO: handle error
}
_ = binary.BigEndian.Uint16(b[:2])