Send and receive hex codes over nodejs socket

Question

I am sending hex code to machine in nodejs socket application and receive hex answer from code below:

socket.on('data', function(data){
  console.log('Socket:'+Buffer.from(data).toString('hex'));
});

In console I receive this: 0104000100150104125d2befbfbdefbfbdefbfbdefbfbdefbfbdefbfbdefbfbdefbfbdefbfbdefbfbdefbfbdefbfbdefbfbd00efbfbdefbfbd

What is expected:

01 04 00 01 00 15 01 04 12 5D 2B FF FF FF FF FF FF FF FF FF FF FF FF 80 00 FF FF

I don't understand why there is additional data.

Answer 1

Seems data is string, not buffer.

just try this code

const data = Buffer.from('01 04 00 01 00 15 01 04 12 5D 2B FF FF FF FF FF FF FF FF FF FF FF FF 80 00 FF FF'.split(' ').map(x => parseInt(x, 16)));
console.log(Buffer.from(data).toString('hex'));
const str = data.toString(); // <- problem!!!
console.log(Buffer.from(str).toString('hex'));

You can't send binary buffer directly, just convert to hex string before and to buffer after for example.

Read this topic Node Buffers, from utf8 to binary