Source: speech_detection_google/svc.js

/***
 * Copyright 2015 RAPP
 *
 * 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.
 *
 * Authors: Konstantinos Panayiotou
 * Contact: klpanagi@gmail.com
 *
 */


/**
 * @fileOverview
 *
 * [Speech-detection-google] RAPP Platform front-end web service.
 *
 *  @author Konstantinos Panayiotou
 *  @copyright Rapp Project EU 2015
 */


var path = require('path');
var Fs = require(path.join(ENV.PATHS.INCLUDE_DIR, 'common', 'fileUtils.js'));

var interfaces = require(path.join(__dirname, 'iface_obj.js'));

const rosSrvName = "/rapp/rapp_speech_detection_google/speech_to_text";


/**
 *  [Speech-Detection-Google]
 *  Handles requests to speech_detection_google RAPP Platform Service
 *
 *  Service Implementation.
 *
 */
function svcImpl(req, resp, ros) {

  if (! req.files.file) {
    let response = new interfaces.client_res();
    response.error = "No image file received";
    resp.sendJson(response);
    return;
  }

  var rosMsg = new interfaces.ros_req();
  rosMsg.filename = req.files.file[0];
  rosMsg.audio_type = req.body.audio_source;
  rosMsg.user = req.username;
  rosMsg.language = req.body.language;

  // ROS-Service response callback.
  function callback(data) {
    Fs.rmFile(req.files.file[0]);
    // Parse rosbridge message and craft client response
    var response = parseRosbridgeMsg(data);
    resp.sendJson(response);
  }

  // ROS-Service onerror callback.
  function onerror(e) {
    Fs.rmFile(req.files.file[0]);
    var response = new interfaces.client_res();
    response.error = e;
    resp.sendJson(response);
  }

  // Call ROS-Service.
  ros.callService(rosSrvName, rosMsg, {success: callback, fail: onerror});
}



/***
 * Crafts response object.
 *
 *  @param {Object} rosbridge_msg - Return message from rosbridge
 *
 *  @returns {Object} response - Response object.
 *  @returns {Array} response.words. An array of the detected-words, with
 *    higher confidence.
 *  @returns {Array} response.alternatives. Array of alternative sentences.
 *    <p> e.g. [['send', 'mail'], ['send', 'email'], ['set', 'mail']...] </p>
 *  @returns {String} response.error - Error message
 */
function parseRosbridgeMsg(rosbridge_msg) {
  const words = rosbridge_msg.words;
  const alternatives = rosbridge_msg.alternatives;
  const error = rosbridge_msg.error;

  var response = new interfaces.client_res();

  if (error) {
    response.error = error;
    return response;
  }

  response.words = words;

  for (let ii = 0; ii < alternatives.length; ii++) {
    response.alternatives.push( alternatives[ii].s );
  }

  return response;
}


module.exports = svcImpl;