Source: recognize-blob.js

/**
 * Copyright 2015 IBM Corp. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use strict';
var BlobStream = require('readable-blob-stream');
var RecognizeStream = require('./recognize-stream.js');
var FilePlayer = require('./file-player.js');
var FormatStream = require('./format-stream.js');
var TimingStream = require('./timing-stream.js');

/**
 * Create and return a RecognizeStream from a File or Blob
 * (e.g. from a file <input>, a dtagdrop targe, or an ajax request)
 *
 * @param {Object} options - Also passed to {MediaElementAudioStream} and to {RecognizeStream}
 * @param {String} options.token - Auth Token - see https://github.com/watson-developer-cloud/node-sdk#authorization
 * @param {Blob|File} options.data - the raw audio data as a Blob or File instance
 * @param {Boolean} [options.play=false] - If a file is set, play it locally as it's being uploaded
 * @param {Boolena} [options.format=true] - pipe the text through a {FormatStream} which performs light formatting
 * @param {Boolena} [options.realtime=options.play] - pipe the text through a {TimingStream} which slows the output down to real-time to match the audio playback.
 *
 * @returns {RecognizeStream}
 */
module.exports = function recognizeBlob(options) {
  if (!options || !options.token) {
    throw new Error("WatsonSpeechToText: missing required parameter: opts.token");
  }

  var recognizeStream = new RecognizeStream(options);
  var stream = new BlobStream(options.data).pipe(recognizeStream);

  if (options.format !== false) {
    stream = stream.pipe(new FormatStream(options));
  }
  if (options.realtime || typeof options.realtime === 'undefined' && options.play) {
    stream = stream.pipe(new TimingStream(options));
    start = Date.now();
  }

  if (options.play) {
    FilePlayer.playFile(options.data).then(function (player) {
      recognizeStream.on('stop', player.stop.bind(player));
    }).catch(function (err) {
      recognizeStream.emit('playback-error', err);
    });
  }

  return stream;
};