browser-serialport/index.js

Robots in the browser. Just like node-serialport but for browser/chrome apps.

'use strict';

var EE = require('events').EventEmitter;
var util = require('util');

var DATABITS = [7, 8];
var STOPBITS = [1, 2];
var PARITY = ['none', 'even', 'mark', 'odd', 'space'];
var FLOWCONTROLS = ['RTSCTS'];

var _options = {
  baudrate: 9600,
  parity: 'none',
  rtscts: false,
  databits: 8,
  stopbits: 1,
  buffersize: 256
};

function convertOptions(options){
  switch (options.dataBits) {
    case 7:
      options.dataBits = 'seven';
      break;
    case 8:
      options.dataBits = 'eight';
      break;
  }

  switch (options.stopBits) {
    case 1:
      options.stopBits = 'one';
      break;
    case 2:
      options.stopBits = 'two';
      break;
  }

  switch (options.parity) {
    case 'none':
      options.parity = 'no';
      break;
  }

  return options;
}

function SerialPort(path, options, openImmediately, callback) {

  EE.call(this);

  var self = this;

  var args = Array.prototype.slice.call(arguments);
  callback = args.pop();
  if (typeof(callback) !== 'function') {
    callback = null;
  }

  options = (typeof options !== 'function') && options || {};

  openImmediately = (openImmediately === undefined || openImmediately === null) ? true : openImmediately;

  callback = callback || function (err) {
    if (err) {
      self.emit('error', err);
    }
  };

  var err;

  options.baudRate = options.baudRate || options.baudrate || _options.baudrate;

  options.dataBits = options.dataBits || options.databits || _options.databits;
  if (DATABITS.indexOf(options.dataBits) === -1) {
    err = new Error('Invalid "databits": ' + options.dataBits);
    callback(err);
    return;
  }

  options.stopBits = options.stopBits || options.stopbits || _options.stopbits;
  if (STOPBITS.indexOf(options.stopBits) === -1) {
    err = new Error('Invalid "stopbits": ' + options.stopbits);
    callback(err);
    return;
  }

  options.parity = options.parity || _options.parity;
  if (PARITY.indexOf(options.parity) === -1) {
    err = new Error('Invalid "parity": ' + options.parity);
    callback(err);
    return;
  }

  if (!path) {
    err = new Error('Invalid port specified: ' + path);
    callback(err);
    return;
  }

  options.rtscts = _options.rtscts;

  if (options.flowControl || options.flowcontrol) {
    var fc = options.flowControl || options.flowcontrol;

    if (typeof fc === 'boolean') {
      options.rtscts = true;
    } else {
      var clean = fc.every(function (flowControl) {
        var fcup = flowControl.toUpperCase();
        var idx = FLOWCONTROLS.indexOf(fcup);
        if (idx < 0) {
          var err = new Error('Invalid "flowControl": ' + fcup + '. Valid options: ' + FLOWCONTROLS.join(', '));
          callback(err);
          return false;
        } else {

          // "XON", "XOFF", "XANY", "DTRDTS", "RTSCTS"
          switch (idx) {
            case 0: options.rtscts = true; break;
          }
          return true;
        }
      });
      if(!clean){
        return;
      }
    }
  }

  options.bufferSize = options.bufferSize || options.buffersize || _options.buffersize;

  // defaults to chrome.serial if no options.serial passed
  // inlined instead of on _options to allow mocking global chrome.serial for optional options test
  options.serial = options.serial || (typeof chrome !== 'undefined' && chrome.serial);

  if (!options.serial) {
    throw new Error('No access to serial ports. Try loading as a Chrome Application.');
  }

  this.options = convertOptions(options);

  this.options.serial.onReceiveError.addListener(function(info){

    switch (info.error) {

      case 'disconnected':
      case 'device_lost':
      case 'system_error':
        err = new Error('Disconnected');
        // send notification of disconnect
        if (self.options.disconnectedCallback) {
          self.options.disconnectedCallback(err);
        } else {
          self.emit('disconnect', err);
        }
        if(self.connectionId >= 0){
          self.close();
        }
        break;
      case 'timeout':
        break;
    }

  });

  this.path = path;

  if (openImmediately) {
    process.nextTick(function () {
      self.open(callback);
    });
  }
}

util.inherits(SerialPort, EE);

SerialPort.prototype.connectionId = -1;

SerialPort.prototype.open = function (callback) {
  var options = {
    bitrate: parseInt(this.options.baudRate, 10),
    dataBits: this.options.dataBits,
    parityBit: this.options.parity,
    stopBits: this.options.stopBits,
    ctsFlowControl: this.options.rtscts
  };

  this.options.serial.connect(this.path, options, this.proxy('onOpen', callback));
};

SerialPort.prototype.onOpen = function (callback, openInfo) {
  if(chrome.runtime.lastError){
    if(typeof callback === 'function'){
      callback(chrome.runtime.lastError);
    }else{
      this.emit('error', chrome.runtime.lastError);
    }
    return;
  }

  this.connectionId = openInfo.connectionId;

  if (this.connectionId === -1) {
    this.emit('error', new Error('Could not open port.'));
    return;
  }

  this.emit('open', openInfo);

  this._reader = this.proxy('onRead');

  this.options.serial.onReceive.addListener(this._reader);

  if(typeof callback === 'function'){
    callback(chrome.runtime.lastError, openInfo);
  }
};

SerialPort.prototype.onRead = function (readInfo) {
  if (readInfo && this.connectionId === readInfo.connectionId) {

    if (this.options.dataCallback) {
      this.options.dataCallback(toBuffer(readInfo.data));
    } else {
      this.emit('data', toBuffer(readInfo.data));
    }

  }
};

SerialPort.prototype.write = function (buffer, callback) {
  if (this.connectionId < 0) {
    var err = new Error('Serialport not open.');
    if(typeof callback === 'function'){
      callback(err);
    }else{
      this.emit('error', err);
    }
    return;
  }

  if (typeof buffer === 'string') {
    buffer = str2ab(buffer);
  }

  //Make sure its not a browserify faux Buffer.
  if (buffer instanceof ArrayBuffer === false) {
    buffer = buffer2ArrayBuffer(buffer);
  }

  this.options.serial.send(this.connectionId, buffer, function(info) {
    if (typeof callback === 'function') {
      callback(chrome.runtime.lastError, info);
    }
  });
};


SerialPort.prototype.close = function (callback) {
  if (this.connectionId < 0) {
    var err = new Error('Serialport not open.');
    if(typeof callback === 'function'){
      callback(err);
    }else{
      this.emit('error', err);
    }
    return;
  }

  this.options.serial.disconnect(this.connectionId, this.proxy('onClose', callback));
};

SerialPort.prototype.onClose = function (callback, result) {
  this.connectionId = -1;
  this.emit('close');

  this.removeAllListeners();
  if(this._reader){
    this.options.serial.onReceive.removeListener(this._reader);
    this._reader = null;
  }

  if (typeof callback === 'function') {
    callback(chrome.runtime.lastError, result);
  }
};

SerialPort.prototype.flush = function (callback) {
  if (this.connectionId < 0) {
    var err = new Error('Serialport not open.');
    if(typeof callback === 'function'){
      callback(err);
    }else{
      this.emit('error', err);
    }
    return;
  }

  var self = this;

  this.options.serial.flush(this.connectionId, function(result) {
    if (chrome.runtime.lastError) {
      if (typeof callback === 'function') {
        callback(chrome.runtime.lastError, result);
      } else {
        self.emit('error', chrome.runtime.lastError);
      }
      return;
    } else {
      callback(null, result);
    }
  });
};

SerialPort.prototype.drain = function (callback) {
  if (this.connectionId < 0) {
    var err = new Error('Serialport not open.');
    if(typeof callback === 'function'){
      callback(err);
    }else{
      this.emit('error', err);
    }
    return;
  }

  if (typeof callback === 'function') {
    callback();
  }
};


SerialPort.prototype.proxy = function () {
  var self = this;
  var proxyArgs = [];

  //arguments isnt actually an array.
  for (var i = 0; i < arguments.length; i++) {
      proxyArgs[i] = arguments[i];
  }

  var functionName = proxyArgs.splice(0, 1)[0];

  var func = function() {
    var funcArgs = [];
    for (var i = 0; i < arguments.length; i++) {
        funcArgs[i] = arguments[i];
    }
    var allArgs = proxyArgs.concat(funcArgs);

    self[functionName].apply(self, allArgs);
  };

  return func;
};

SerialPort.prototype.set = function (options, callback) {
  this.options.serial.setControlSignals(this.connectionId, options, function(result){
    callback(chrome.runtime.lastError, result);
  });
};

SerialPort.prototype.isOpen = function () {
  return this.connectionId > -1;
};

function SerialPortList(callback) {
  if (typeof chrome != 'undefined' && chrome.serial) {
    chrome.serial.getDevices(function(ports) {
      var portObjects = new Array(ports.length);
      for (var i = 0; i < ports.length; i++) {
        portObjects[i] = {
          comName: ports[i].path,
          manufacturer: ports[i].displayName,
          serialNumber: '',
          pnpId: '',
          locationId:'',
          vendorId: '0x' + (ports[i].vendorId||0).toString(16),
          productId: '0x' + (ports[i].productId||0).toString(16)
        };
      }
      callback(chrome.runtime.lastError, portObjects);
    });
  } else {
    callback(new Error('No access to serial ports. Try loading as a Chrome Application.'), null);
  }
}

// Convert string to ArrayBuffer
function str2ab(str) {
  var buf = new ArrayBuffer(str.length);
  var bufView = new Uint8Array(buf);
  for (var i = 0; i < str.length; i++) {
    bufView[i] = str.charCodeAt(i);
  }
  return buf;
}

// Convert buffer to ArrayBuffer
function buffer2ArrayBuffer(buffer) {
  var buf = new ArrayBuffer(buffer.length);
  var bufView = new Uint8Array(buf);
  for (var i = 0; i < buffer.length; i++) {
    bufView[i] = buffer[i];
  }
  return buf;
}

function toBuffer(ab) {
  var buffer = new Buffer(ab.byteLength);
  var view = new Uint8Array(ab);
  for (var i = 0; i < buffer.length; ++i) {
      buffer[i] = view[i];
  }
  return buffer;
}

module.exports = {
  SerialPort: SerialPort,
  list: SerialPortList,
  buffer2ArrayBuffer: buffer2ArrayBuffer,
  used: [] //TODO: Populate this somewhere.
};