Espruino + Bluetooth Slack Bookmarklet!

Ever wanted to control your Espruinos from Slack? Now you can :)

• In Chrome, open 'Bookmrk manager'
  
• Go to 'Bookmarks bar', right-click and add bookmark
  

• Type 'slack-espruino' as the name, then paste the code below into the URL and save:

  javascript:(function() {
  var knownMessages = [];
  
  function write(str) {
  var u = new Uint8Array(str.length);
  for (var i=0;i<str.length;i++)
    u[i] = str.charCodeAt(i);
  console.log("Writing ",JSON.stringify(str));
  bluetoothTX.writeValue(u.buffer).then(function() {
    console.log("Written!");
  })
  }
  function poll() {
  var m = document.querySelectorAll(".c-message__message_blocks");
  for (var i=0;i<m.length;i++) {
    if (knownMessages.includes(m[i])) continue;
    knownMessages.push(m[i]);
    var msg = m[i].innerText.trim();
    console.log("New message:",msg);
    if (msg.startsWith("Espruino:"))
      write(msg.substr(9).trim()+"\n");      
  }
  }
  
  var bluetoothDevice, bluetoothServer, bluetoothTX;
  navigator.bluetooth.requestDevice({ filters: [{services: ["6e400001-b5a3-f393-e0a9-e50e24dcca9e"]},{namePrefix: "Puck"}]}).then(device => {
  console.log('Connecting to GATT Server...');
  bluetoothDevice = device;
  return device.gatt.connect();
  }).then(function(server) {
  console.log("Connected");
  bluetoothServer = server;
  return server.getPrimaryService("6e400001-b5a3-f393-e0a9-e50e24dcca9e");
  }).then(function(service) {
  return service.getCharacteristic("6e400002-b5a3-f393-e0a9-e50e24dcca9e");
  }).then(function(char) {
  bluetoothTX = char;
  console.log("Completed!");
  setInterval(poll,1000);
  });
  })();
  

• Now open Slack for the web browser. This can be a pain on Android if you have the app installed, requiring you to view the sign-in page 'as desktop browser'

• Go to the specific chat you care about

• Open the slack-espruino bookmark you just made (or copy/paste the code above into the address bar)

• Choose an Espruino device in the bluetooth popup that appears

• Any message that anyone writes in the conversation that starts with Espruino: (has to be the same capitalisation) will be sent to Espruino. For example: Espruino:LED.set() will turn the LED on!