Writing a primitive PC volume control over LAN using NodeJS

What adds to the frustration is that even many developers rightly consider Seven to be an antiquity and are too lazy to support it, so installing the right environment is increasingly a freezing search for the right versions (more and more often I’m thinking about finally switching to Linux, but that’s not about that now). Situations especially set fire to the chair when the developers of some popular package suddenly decide that they I really need a new function for determining the system version in the installer, which is not in the seven, so they will no longer support it (the reason why it is impossible to install NodeJS older than version 14 without crutches). By the way, the time has come for eight fans to rejoice.

#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <Windows.h>
#include <mmsystem.h>
#include <initguid.h>
#include <mmdeviceapi.h>
#include <endpointvolume.h>
#include <functiondiscoverykeys_devpkey.h> // Need to use PKEY_Device_FriendlyName
static const char VOLUME_RANGE_ERR[] = "Volume must be a fractional number ranging from 0 to 1";
static const char NO_ENDPOINTS_ERR[] = "No endpoints found.";
static const char OK_MSG[] = "Ok";

extern "C" int setVolume(double newVolume) {
  if (newVolume < 0 || newVolume > 1) {
    std::cout<<VOLUME_RANGE_ERR<< std::endl;
    return 1;
  }
  HRESULT hr = S_OK;
  UINT count = 0;
  IMMDeviceEnumerator *pEnumerator = NULL;
  IMMDeviceCollection *pCollection = NULL;
  IMMDevice *pEndpoint = NULL;
  IPropertyStore *pProps = NULL;
  LPWSTR pwszID = NULL;
  CoInitialize(NULL);
  hr = CoCreateInstance(CLSID_MMDeviceEnumerator, NULL,CLSCTX_ALL, IID_IMMDeviceEnumerator, (void**)&pEnumerator);
  hr = pEnumerator->EnumAudioEndpoints(eRender, DEVICE_STATE_ACTIVE,&pCollection);
  // ** use "eCapture" for microphones and "eRender" for speakers.
  hr = pCollection->GetCount(&count);
  if (count == 0) {
    std::cout << NO_ENDPOINTS_ERR << std::endl;
    return 2;
  }
  for (UINT i = 0; i < count; i++) {
    hr = pCollection->Item(i, &pEndpoint);
    hr = pEndpoint->GetId(&pwszID);
    IAudioEndpointVolume *endpointVolume = NULL;
    pEnumerator->GetDevice(pwszID, &pEndpoint);
    pEndpoint->Activate(__uuidof(IAudioEndpointVolume),CLSCTX_INPROC_SERVER, NULL, (LPVOID *)&endpointVolume);
    endpointVolume->SetMasterVolumeLevelScalar((float)newVolume, NULL);
    endpointVolume->Release();
  }
  return 0;
}

extern "C" void showDevices() {
  UINT numDevices = waveInGetNumDevs();
  std::cout << "Number of input devices: " << numDevices << std::endl;
  for (UINT i = 0; i < numDevices; i++) {
    WAVEINCAPS deviceInfo;
    if (waveInGetDevCaps(i, &deviceInfo, sizeof(deviceInfo)) == MMSYSERR_NOERROR) {
      std::cout << "Input device " << i << ": " << deviceInfo.szPname << std::endl;
      std::cout << "Channels: " << deviceInfo.wChannels << std::endl;
      std::cout << std::endl;
    }
  }
  numDevices = waveOutGetNumDevs();
  std::cout << "Number of output devices: " << numDevices << std::endl;
  for (UINT i = 0; i < numDevices; i++) {
    WAVEOUTCAPS deviceInfo;
    if (waveOutGetDevCaps(i, &deviceInfo, sizeof(deviceInfo)) == MMSYSERR_NOERROR) {
      std::cout << "Output device " << i << ": " << deviceInfo.szPname << std::endl;
      std::cout << "Channels: " << deviceInfo.wChannels << std::endl;
      std::cout << std::endl;
    }
  }
}

I used the showDevices function only for debugging, but if desired, it would not be difficult to add support for multiple devices.

const express = require('express');
const server = express();
const { load, RetType, ParamsType } = require('ffi-rs');
const EventLogger = require('node-windows').EventLogger;

const SERVER_PORT = 12345;
const logger = new EventLogger('New windows-event logger');

const messageCodes = {
  0: "Ok",
  1: "Volume must be a fractional number ranging from 0 to 1",
  2: "No endpoints found.",
  3: "Volume is not specified",
  5: "NodeJS AudioManager server start at port " + SERVER_PORT,
  42: "Something went wrong when tried using extern DLL (unknown error)",
};

// Add headers before the routes are defined
server.use(function (req, res, next) {
  res.setHeader('Access-Control-Allow-Origin', '*');
  // Возможно тут стоит добавить адрес компьютера на котором вы хотите запускать сервер для пущей безопасности
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST');
  // Мы используем этот же сервер для хостинга веб-интерфейса
  res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With, content-type');
  next();
});

server.use(express.json({ limit: '1mb' }));
server.use(express.static(__dirname + '/../public'));
// Возвращаем index.html из папки public при запросе http://127.0.0.1:SERVER_PORT/

server.post('/api/setvolume', function(request, response) {
  const input = request.body;
  let externalResult = 0;
  if (!input.hasOwnProperty('volume')) {
    response.status(422);
    response.send(messageCodes[3]);
    return;
  }
  const newVolume = parseFloat(input['volume']);
  if (isNaN(newVolume) || newVolume < 0 || newVolume > 1) {
    response.status(422);
    response.send(messageCodes[1]);
    return;
  }

  try {
    externalResult = load({
      library: __dirname + '/../test.dll', // path to the dynamic library file
      funcName: 'setVolume', // the name of the function to call
      retType: RetType.I32, // the return value type
      paramsType: [ParamsType.Double], // the parameter types
      paramsValue: [newVolume] // the actual parameter values
    });
  } catch(err) {
    logger.error('Something went wrong when tried using extern DLL: ' + err.name + ' ' + err.message, 42);
    console.error(err);
    response.send(err.message);
    return;
  }

  if (externalResult != 0) {
    console.error(messageCodes[externalResult]);
  }

  response.send(messageCodes[externalResult]);
});

server.listen(SERVER_PORT, () => {
  logger.info(messageCodes[5], 5); // Second param is event code, use your own
  console.log(messageCodes[5]);
  console.log('Open http://127.0.0.1:'+ SERVER_PORT +' in your browser');
});

The code seems to be elementary and does not need comments

const path = require('path');
const Service = require('node-windows').Service;

// Создаем новый объект службы
const svc = new Service({
  name:'NodeJS AudioManager',
  description: 'NodeJS AudioManager as Windows Service',
  script: path.resolve(__dirname)+'\\server.js', // путь к приложению
  maxRetries: 10, // не перезапускать службу после 10 падений (защита от цикла)
});

// Слушаем событие 'install' и запускаем службу
svc.on('install',function(){
  svc.start();
});

// Устанавливаем службу
svc.install();

For deletion, the script at the beginning is almost similar, except that the event will be different:

// Слушаем событие 'uninstall', пишем сообщение
svc.on('uninstall', function(){
  console.log('Uninstall complete.');
  console.log('The service exists: ', svc.exists);
});

// Удаляем службу
svc.uninstall();

<!DOCTYPE html>
<html>
<head>
  <title>Volume</title>
  <link rel="apple-touch-icon" sizes="180x180" href="https://habr.com/apple-touch-icon.png">
  <link rel="icon" type="image/svg+xml" href="http://habr.com/favicon.svg" sizes="any" />
  <link rel="icon" type="image/png" sizes="32x32" href="http://habr.com/favicon-small.png">
  <link rel="manifest" href="http://habr.com/manifest.json">
  <link rel="mask-icon" href="http://habr.com/safari-pinned.svg" color="#5bbad5">
  <meta name="msapplication-TileColor" content="#00aba9">
  <meta name="theme-color" content="#418598">
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />

  <style>
    html, body { margin: 0; background: #202020; color: #efefef; }
    body { overflow: hidden; }
    .container { margin: 0 auto; display: flex; flex-direction: column; max-width: 800px; height: 100vh; }
    .input-container { transform: rotate(270deg); display: flex; }
    h1 { text-align: center; }
    input { width: 400px; }

    @media (max-width: 700px) {
      .input-container { flex-grow: 1; }
    }
  </style>
</head>
<body>
  <div class="container">
    <h1>Control PC volume</h1>
    <div class="input-container">
      <input type="range" min="0" max="1" step="0.02" value="0.5" onchange="onInputChange();" id="volume-change-input"/>
    </div>
  </div>
  <script>
    function onInputChange() {
      var newValue = document.getElementById("volume-change-input").value;
      fetch("/api/setvolume", {
        method: "post",
        headers: {'Accept': 'application/json', 'Content-Type': 'application/json'},
        //make sure to serialize your JSON body
        body: JSON.stringify({ volume: newValue })
      }).then( (response) => {
        //do something awesome that makes the world a better place
      });
    }
  </script>
</body>
</html>

{
  "name": "AudioManager",
  "version": "1.0.0",
  "description": "Control your computer's sound from any device on the network, without any additional applications.",
  "main": "server.js",
  "scripts": {
    "dev": "node scripts/server.js",
    "setup": "node scripts/setup.js",
    "uninstall": "node scripts/uninstall.js"
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/Psychosynthesis/AudioManager.git"
  },
  "homepage": "https://github.com/Psychosynthesis/SimpleServer#readme",
  "author": "Nick G.",
  "license": "MIT",
  "dependencies": {
    "express": "^4.18.2",
    "ffi-rs": "^1.0.18",
    "node-windows": "^1.0.0-beta.8"
  }
}

Please note that here I still have older versions, ffi-rs has definitely become better since then.