/*!
* ws: a node.js websocket client
* Copyright(c) 2011 Einar Otto Stangvik <einaros@gmail.com>
* MIT Licensed
*/
var events = require('events')
, util = require('util')
, EventEmitter = events.EventEmitter
, ErrorCodes = require('./ErrorCodes')
, bufferUtil = require('./BufferUtil').BufferUtil
, PerMessageDeflate = require('./PerMessageDeflate');
/**
* HyBi Sender implementation
*/
function Sender(socket, extensions) {
if (this instanceof Sender === false) {
throw new TypeError("Classes can't be function-called");
}
events.EventEmitter.call(this);
this._socket = socket;
this.extensions = extensions || {};
this.firstFragment = true;
this.compress = false;
this.messageHandlers = [];
this.processing = false;
}
/**
* Inherits from EventEmitter.
*/
util.inherits(Sender, events.EventEmitter);
/**
* Sends a close instruction to the remote party.
*
* @api public
*/
Sender.prototype.close = function(code, data, mask, cb) {
if (typeof code !== 'undefined') {
if (typeof code !== 'number' ||
!ErrorCodes.isValidErrorCode(code)) throw new Error('first argument must be a valid error code number');
}
code = code || 1000;
var dataBuffer = new Buffer(2 + (data ? Buffer.byteLength(data) : 0));
writeUInt16BE.call(dataBuffer, code, 0);
if (dataBuffer.length > 2) dataBuffer.write(data, 2);
var self = this;
this.messageHandlers.push(function(callback) {
self.frameAndSend(0x8, dataBuffer, true, mask);
callback();
if (typeof cb == 'function') cb();
});
this.flush();
};
/**
* Sends a ping message to the remote party.
*
* @api public
*/
Sender.prototype.ping = function(data, options) {
var mask = options && options.mask;
var self = this;
this.messageHandlers.push(function(callback) {
self.frameAndSend(0x9, data || '', true, mask);
callback();
});
this.flush();
};
/**
* Sends a pong message to the remote party.
*
* @api public
*/
Sender.prototype.pong = function(data, options) {
var mask = options && options.mask;
var self = this;
this.messageHandlers.push(function(callback) {
self.frameAndSend(0xa, data || '', true, mask);
callback();
});
this.flush();
};
/**
* Sends text or binary data to the remote party.
*
* @api public
*/
Sender.prototype.send = function(data, options, cb) {
var finalFragment = options && options.fin === false ? false : true;
var mask = options && options.mask;
var compress = options && options.compress;
var opcode = options && options.binary ? 2 : 1;
if (this.firstFragment === false) {
opcode = 0;
compress = false;
} else {
this.firstFragment = false;
this.compress = compress;
}
if (finalFragment) this.firstFragment = true
var compressFragment = this.compress;
var self = this;
this.messageHandlers.push(function(callback) {
self.applyExtensions(data, finalFragment, compressFragment, function(err, data) {
if (err) {
if (typeof cb == 'function') cb(err);
else self.emit('error', err);
return;
}
self.frameAndSend(opcode, data, finalFragment, mask, compress, cb);
callback();
});
});
this.flush();
};
/**
* Frames and sends a piece of data according to the HyBi WebSocket protocol.
*
* @api private
*/
Sender.prototype.frameAndSend = function(opcode, data, finalFragment, maskData, compressed, cb) {
var canModifyData = false;
if (!data) {
try {
this._socket.write(new Buffer([opcode | (finalFragment ? 0x80 : 0), 0 | (maskData ? 0x80 : 0)].concat(maskData ? [0, 0, 0, 0] : [])), 'binary', cb);
}
catch (e) {
if (typeof cb == 'function') cb(e);
else this.emit('error', e);
}
return;
}
if (!Buffer.isBuffer(data)) {
canModifyData = true;
if (data && (typeof data.byteLength !== 'undefined' || typeof data.buffer !== 'undefined')) {
data = getArrayBuffer(data);
} else {
//
// If people want to send a number, this would allocate the number in
// bytes as memory size instead of storing the number as buffer value. So
// we need to transform it to string in order to prevent possible
// vulnerabilities / memory attacks.
//
if (typeof data === 'number') data = data.toString();
data = new Buffer(data);
}
}
var dataLength = data.length
, dataOffset = maskData ? 6 : 2
, secondByte = dataLength;
if (dataLength >= 65536) {
dataOffset += 8;
secondByte = 127;
}
else if (dataLength > 125) {
dataOffset += 2;
secondByte = 126;
}
var mergeBuffers = dataLength < 32768 || (maskData && !canModifyData);
var totalLength = mergeBuffers ? dataLength + dataOffset : dataOffset;
var outputBuffer = new Buffer(totalLength);
outputBuffer[0] = finalFragment ? opcode | 0x80 : opcode;
if (compressed) outputBuffer[0] |= 0x40;
switch (secondByte) {
case 126:
writeUInt16BE.call(outputBuffer, dataLength, 2);
break;
case 127:
writeUInt32BE.call(outputBuffer, 0, 2);
writeUInt32BE.call(outputBuffer, dataLength, 6);
}
if (maskData) {
outputBuffer[1] = secondByte | 0x80;
var mask = getRandomMask();
outputBuffer[dataOffset - 4] = mask[0];
outputBuffer[dataOffset - 3] = mask[1];
outputBuffer[dataOffset - 2] = mask[2];
outputBuffer[dataOffset - 1] = mask[3];
if (mergeBuffers) {
bufferUtil.mask(data, mask, outputBuffer, dataOffset, dataLength);
try {
this._socket.write(outputBuffer, 'binary', cb);
}
catch (e) {
if (typeof cb == 'function') cb(e);
else this.emit('error', e);
}
}
else {
bufferUtil.mask(data, mask, data, 0, dataLength);
try {
this._socket.write(outputBuffer, 'binary');
this._socket.write(data, 'binary', cb);
}
catch (e) {
if (typeof cb == 'function') cb(e);
else this.emit('error', e);
}
}
}
else {
outputBuffer[1] = secondByte;
if (mergeBuffers) {
data.copy(outputBuffer, dataOffset);
try {
this._socket.write(outputBuffer, 'binary', cb);
}
catch (e) {
if (typeof cb == 'function') cb(e);
else this.emit('error', e);
}
}
else {
try {
this._socket.write(outputBuffer, 'binary');
this._socket.write(data, 'binary', cb);
}
catch (e) {
if (typeof cb == 'function') cb(e);
else this.emit('error', e);
}
}
}
};
/**
* Execute message handler buffers
*
* @api private
*/
Sender.prototype.flush = function() {
if (this.processing) return;
var handler = this.messageHandlers.shift();
if (!handler) return;
this.processing = true;
var self = this;
handler(function() {
self.processing = false;
self.flush();
});
};
/**
* Apply extensions to message
*
* @api private
*/
Sender.prototype.applyExtensions = function(data, fin, compress, callback) {
if (compress && data) {
if ((data.buffer || data) instanceof ArrayBuffer) {
data = getArrayBuffer(data);
}
this.extensions[PerMessageDeflate.extensionName].compress(data, fin, callback);
} else {
callback(null, data);
}
};
module.exports = Sender;
function writeUInt16BE(value, offset) {
this[offset] = (value & 0xff00)>>8;
this[offset+1] = value & 0xff;
}
function writeUInt32BE(value, offset) {
this[offset] = (value & 0xff000000)>>24;
this[offset+1] = (value & 0xff0000)>>16;
this[offset+2] = (value & 0xff00)>>8;
this[offset+3] = value & 0xff;
}
function getArrayBuffer(data) {
// data is either an ArrayBuffer or ArrayBufferView.
var array = new Uint8Array(data.buffer || data)
, l = data.byteLength || data.length
, o = data.byteOffset || 0
, buffer = new Buffer(l);
for (var i = 0; i < l; ++i) {
buffer[i] = array[o+i];
}
return buffer;
}
function getRandomMask() {
return new Buffer([
~~(Math.random() * 255),
~~(Math.random() * 255),
~~(Math.random() * 255),
~~(Math.random() * 255)
]);
}