Text-to-speech Bookmarklet

bookmarklet.js

(function() {
  var script = document.createElement('script');
  script.setAttribute('src', 'https://bit.ly/426oCvn');
  script.onload = function() {
    textToSpeech('YOURKEYHERE', getRandomVoice());
  };
  document.body.appendChild(script);
})();

text-to-speech.js

const readabilityLibraryUrl = "https://tinyurl.com/yfdzwf96"
const speechLibraryUrl = 'https://tinyurl.com/44vzwvdc';
const loginUrl = 'https://uksouth.api.cognitive.microsoft.com/sts/v1.0/issuetoken';
const batchSize = 5;

function addScript(src) {
  return new Promise(function(resolve, reject) {
    var script = document.createElement('script');
    script.setAttribute('src', src);
    script.onload = resolve;
    script.onerror = reject;
    document.body.appendChild(script);
  });
}

function getRandomVoice() {
  const voices = [
    'en-GB-AbbiNeural',
    'en-GB-AlfieNeural',
    'en-GB-BellaNeura',
    'en-GB-ElliotNeural',
    'en-GB-EthanNeural',
    'en-GB-HollieNeural',
    'en-GB-LibbyNeural',
    'en-GB-MaisieNeural',
    'en-GB-NoahNeural',
    'en-GB-OliverNeural',
    'en-GB-OliviaNeural',
    'en-GB-RyanNeural1',
    'en-GB-SoniaNeural1',
    'en-GB-ThomasNeural'
  ];

  const randomIndex = Math.floor(Math.random() * voices.length);
  return voices[randomIndex];
}

function getAuthorizationToken(apiKey) {
  return new Promise(function(resolve, reject) {
    const request = new XMLHttpRequest();
    request.open('POST', loginUrl);
    request.setRequestHeader('Content-Type', 'application/json');
    request.setRequestHeader('Ocp-Apim-Subscription-Key', apiKey)
    request.onload = () => {
      if (request.status == 200) {
        resolve(request.responseText);
      } else {
        reject("File not Found");
      }
    }
    request.send();
  });
}


async function textToSpeech(apiKey, voiceName, text) {
  const allResults = await Promise.all([
    getAuthorizationToken(apiKey),
    addScript(speechLibraryUrl),
    addScript(readabilityLibraryUrl)
  ]);

  class AudioCallback extends SpeechSDK.PushAudioOutputStreamCallback {
    constructor(sourceBuffer) {
      super();
      this.buffersReceived = 0;
      this.pendingBuffers = [];
      this.sourceBuffer = sourceBuffer;
      this.timer = null;

      var that = this;
      this.sourceBuffer.addEventListener('updateend', function (_) {
        that.processPendingData();
      });
    }

    write(dataBuffer) {
      console.log('Received data');
      this.pendingBuffers.push(dataBuffer);
      this.processPendingData();
    }

    processPendingData() {
      if (this.pendingBuffers.length && !this.sourceBuffer.updating) {
        try {
          this.sourceBuffer.appendBuffer(this.pendingBuffers[0]);
          this.pendingBuffers.shift();
        } catch (error) {
          if (error instanceof DOMException && error.name === 'QuotaExceededError') {
            //console.log('Buffers full: delaying processing');
            if (!this.timer) {
              this.timer = window.setTimeout(() => {
                this.processPendingData();
                this.timer = null;
              }, 1000);
            }
          } else {
            throw error;
          }
        }
      }
    }
  }
  const authorizationToken = allResults[0];

  var text = text || readability.grabArticle().innerText.replace(/\.([A-Za-z])/g, ".\n\n$1");
  const body = document.querySelector('body');
  body.innerHTML = '';

  var mediaSource = new MediaSource();
  const objectURL = URL.createObjectURL(mediaSource);

  var audioPlayer = document.createElement('audio');
  audioPlayer.controls = true;
  audioPlayer.src = objectURL;
  body.appendChild(audioPlayer);

  await new Promise(function(resolve, reject) {
    function _sourceOpened() {
      mediaSource.removeEventListener('sourceopen', _sourceOpened);
      resolve();
    }
    mediaSource.addEventListener('sourceopen', _sourceOpened);
  });

  var sourceBuffer = mediaSource.addSourceBuffer('audio/mpeg');
  var audioCallback = new AudioCallback(sourceBuffer);
  var audioConfig = SpeechSDK.AudioConfig.fromStreamOutput(audioCallback);
  var serviceRegion = "uksouth";
  var speechConfig = SpeechSDK.SpeechConfig.fromAuthorizationToken(authorizationToken, serviceRegion);

  speechConfig.speechSynthesisOutputFormat = SpeechSDK.SpeechSynthesisOutputFormat.Audio48Khz192KBitRateMonoMp3;
  speechConfig.speechSynthesisVoiceName = voiceName;

  var synthesizer = new SpeechSDK.SpeechSynthesizer(speechConfig, audioConfig);
  //console.log(text);

  audioPlayer.play();

  paragraphs = text.split('\n').filter(e => e);
  while (paragraphs.length) {
    var text = "";
    var noParas = Math.min(batchSize, paragraphs.length);
    for (var i = 0; i < noParas; i++) {
      text += paragraphs.shift() + '\n';
    }
    console.log(text);
    await new Promise(function(resolve, reject) {
      synthesizer.speakTextAsync(text, resolve, reject);
    });
  }

  console.log('Synthesis finished');
  mediaSource.endOfStream();
  synthesizer.close();
}

A quick and dirty bookmarklet that translates article content into an mp3 file using the Microsoft Azure text-to-speech APIs