Node.js TCP server to transmit messages to connected clients when GPIO events happen. Can be used to mute and unmute a Zoom call with a physical button.

client.js

const net = require("net");
const { spawn } = require("child_process");

const client = new net.Socket();

client.connect(9000, "192.168.1.26", function () {
  console.log("Connected to button server");
});

const unmuteScript = `
  tell application "System Events"
    tell process "zoom.us"
      click menu item "Unmute audio" of menu "Meeting" of menu bar 1
    end tell
  end tell
`;

const muteScript = `
  tell application "System Events"
    tell process "zoom.us"
      click menu item "Mute audio" of menu "Meeting" of menu bar 1
    end tell
  end tell
`;

client.on("data", function (data) {
  console.log("Received: " + data);

  const convertedData = Buffer.from(data).toString();

  if (convertedData === "RED\n") {
    console.log("yo");
    const newProcess = spawn("osascript", ["-e", muteScript]);

    newProcess.stdout.on("data", (data) => {
      console.log(`stdout: ${data}`);
    });

    newProcess.stderr.on("data", (data) => {
      console.error(`stderr: ${data}`);
    });

    newProcess.on("close", (code) => {
      console.log(`child process exited with code ${code}`);
    });
  }

  if (convertedData === "GREEN\n") {
    const newProcess = spawn("osascript", ["-e", unmuteScript]);

    newProcess.stdout.on("data", (data) => {
      console.log(`stdout: ${data}`);
    });

    newProcess.stderr.on("data", (data) => {
      console.error(`stderr: ${data}`);
    });

    newProcess.on("close", (code) => {
      console.log(`child process exited with code ${code}`);
    });
  }
});

client.on("close", function () {
  console.log("Connection closed");
});

server.js

const net = require('net');
const Gpio = require('onoff').Gpio;

const buttonRed = new Gpio(27, 'in', 'both', { debounceTimeout: 10 });
const buttonGreen = new Gpio(17, 'in', 'both', { debounceTimeout: 10 });

buttonRed.watch((err, value) => {
  if (err) {
    throw err;
  }

  if (value) {
    currentClients.forEach((client) => client.write("RED\n"));

    console.log("Red button press!");
  }
});

buttonGreen.watch((err, value) => {
  if (err) {
    throw err;
  }

  if (value) {
    currentClients.forEach((client) => client.write("GREEN\n"));

    console.log("Green button press!");
  }
});

const server = net.createServer();

let currentClients = [];
let connectionId = 0;

server.on('connection', handleConnection);

server.listen(9000, function () {
  console.log(`Buttons server listening on port 9000`);
});

function handleConnection(conn) {
  const remoteAddress = conn.remoteAddress + ':' + conn.remotePort;

  conn.connectionId = connectionId++;

  currentClients = [...currentClients, conn];

  console.log(`[${conn.connectionId}] New client connection from ${remoteAddress}`);

  conn.on('data', onConnectionData);
  conn.once('close', onConnectionClose);
  conn.on('error', onConnectionError);

  function onConnectionData(data) {
    console.log(`[${conn.connectionId}] Message from ${remoteAddress}: ${data}`);

    conn.write("ACK");
  }

  function onConnectionClose() {
    currentClients = currentClients.filter(({ connectionId }) => connectionId !== conn.connectionId);

    console.log(`[${conn.connectionId}] Connection from ${remoteAddress} closed`);
  }

  function onConnectionError(error) {
    console.log(`[${conn.connectionId}] Connection ${remoteAddress} error: ${error.message}`);
  }
}

process.on('SIGINT', _ => {
  buttonRed.unexport();
  buttonGreen.unexport();

  process.exit();
});