ws_server.js

const WebSocket = require('ws');
const fs = require('fs');
const argv = require('minimist')(process.argv.slice(2));
const recordingPath = argv._.length ? argv._[0] : '/tmp/audio.raw';
const port = argv.port && parseInt(argv.port) ? parseInt(argv.port) : 3001
let wstream;

console.log(`listening on port ${port}, writing incoming raw audio to file ${recordingPath}`);

const wss = new WebSocket.Server({
    port,
    handleProtocols: (protocols, req) => {
        return 'audio.drachtio.org';
    }
});

wss.on('connection', (ws, req) => {
    console.log(`received connection from ${req.connection.remoteAddress}`);
    wstream = fs.createWriteStream(recordingPath);

    ws.on('message', (message) => {
        if (typeof message === 'string') {
            console.log(`received message: ${message}`);
        } else if (message instanceof Buffer) {
            wstream.write(message);
        }
    });

    ws.on('close', (code, reason) => {
        console.log(`socket closed ${code}:${reason}`);
        wstream.end();
    });
});