Node.js Google Text-To-Speech API Hacking

google-tts-example.js

var googleTTS = require('./google-tts');

var opts = {
  text: 'hello world',
  lang: 'en',
  speed: 1,
  timeout: 10000
};

googleTTS(opts, function (err, url) {
  if (err) {
    console.error(err.stack);
    return;
  }

  console.log('     Text => ' + opts.text);
  console.log('Audio URL => ' + url)
});

google-tts.js

var https = require('https');
var url = require('url');
var host = 'translate.google.com';

function XL (a, b) {
  for (var c = 0; c < b.length - 2; c += 3) {
    var d = b.charAt(c + 2);
    d = d >= 'a' ? d.charCodeAt(0) - 87 : Number(d);
    d = b.charAt(c + 1) == '+' ? a >>> d : a << d;
    a = b.charAt(c) == '+' ? a + d & 4294967295 : a ^ d;
  }
  return a;
}

/**
 * Generate API Token
 *
 * @param   {String} text
 * @param   {String} key
 * @return  {String} token
 */
function getGoogleApiToken (text, key) {
  var a = text, b = key, d = b.split('.');
  b = Number(d[0]) || 0;
  for (var e = [], f = 0, g = 0; g < a.length; g++) {
    var m = a.charCodeAt(g);
    128 > m ? e[f++] = m : (2048 > m ? e[f++] = m >> 6 | 192 : (55296 == (m & 64512) && g + 1 < a.length && 56320 == (a.charCodeAt(g + 1) & 64512) ? (m = 65536 + ((m & 1023) << 10) + (a.charCodeAt(++g) & 1023),
    e[f++] = m >> 18 | 240,
    e[f++] = m >> 12 & 63 | 128) : e[f++] = m >> 12 | 224,
    e[f++] = m >> 6 & 63 | 128),
    e[f++] = m & 63 | 128);
  }
  a = b;
  for (f = 0; f < e.length; f++) {
    a += e[f];
    a = XL(a, '+-a^+6');
  }
  a = XL(a, '+-3^+b+-f');
  a ^= Number(d[1]) || 0;
  0 > a && (a = (a & 2147483647) + 2147483648);
  a = a % 1E6;
  return a.toString() + '.' + (a ^ b);
};

/**
 * Get Key from https://translate.google.com
 *
 * @param   {Function}  callback(err: Error, key: String)
 * @param   {Number!}   timeout  default is 10000ms
 */
function getGoogleApiKey (callback, timeout) {
  var cb = typeof callback === 'function' ? callback : function () {};
  var timeout = timeout || 10 * 1000;

  var options = {
    hostname: host,
    port: 443,
    path: '/',
    method: 'GET'
  };

  var req = https.request(options, function (res) {
    if (res.statusCode !== 200) {
      cb(new Error('request to ' + options.hostname + ' failed, status code = ' + res.statusCode + ' (' + res.statusMessage + ')'));
      return;
    }

    var buffer = [];
    res.on('data', function (chunk) {
      buffer.push(chunk.toString());
    });
    res.on('end', function(){
      var TKK = null;

      try {
        var html = buffer.join();
        eval(html.match(/TKK=eval\(\'\(.*\)\'\);/g)[0]);  // TKK = '405291.1334555331'
        if (TKK === null) throw null;
      } catch (e) {
        cb(new Error('get key failed from google'), null);
        return;
      }

      cb(null, TKK);
      return;
    });
    res.on('error', function (err) {
      cb(err, null);
      return;
    });
  });

  req.setTimeout(timeout, function () {
    req.abort();
    cb(new Error('request to ' + options.hostname + ' timeout'), null);
    return;
  });

  req.on('error', function(err) {
    cb(err, null);
    return;
  });

  req.end();
}

/**
 * Generate "Google TTS" audio link
 *
 * @param   {String}  text
 * @param   {String}  key
 * @param   {String!} lang   default is 'en'
 * @param   {Number!} speed  show = 0.24, default is 1
 * @return  {String}  url
 */
function getSpeechUrl (text, key, lang, speed) {
  if (typeof text !== 'string' || text.length === 0) {
    throw new TypeError('text should be a string');
  }

  if (typeof key !== 'string' || key.length === 0) {
    throw new TypeError('key should be a string');
  }

  if (typeof lang !== 'undefined' && (typeof lang !== 'string' || lang.length === 0)) {
    throw new TypeError('lang should be a string');
  }

  if (typeof speed !== 'undefined' && typeof speed !== 'number') {
    throw new TypeError('speed should be a number');
  }

  return 'https://' + host + '/translate_tts' + url.format({
    query: {
      ie: 'UTF-8',
      q: text,
      tl: lang || 'en',
      total: 1,
      idx: 0,
      textlen: text.length,
      tk: getGoogleApiToken(text, key),
      client: 't',
      prev: 'input',
      ttsspeed: speed || 1
    }
  });
};

/**
 * get "Google TTS" audio URL
 *
 * @param   {Object}   options
 *          {String}   options.text
 *          {String!}  options.lang     default is 'en'
 *          {Number!}  options.speed    show = 0.24, default is 1
 *          {Number!}  options.timeout  default is 10000ms
 *
 * @param   {Function} callback(err: Error, url: String)
 */
module.exports = function (options, callback) {
  var cb = typeof callback === 'function' ? callback : function () {};

  if (typeof options !== 'object') {
    cb(new TypeError('options should be an object'), null);
    return;
  }

  getGoogleApiKey(function (err, apiKey) {
    if (err) {
      cb(err, null);
      return;
    }

    // get API
    try {
      var url = getSpeechUrl(options.text, apiKey, options.lang, options.speed);
      cb(null, url);
    } catch (err) {
     cb(err, null);
    }
  }, options.timeout);
};