/*!
* ws: a node.js websocket client
* Copyright(c) 2011 Einar Otto Stangvik <einaros@gmail.com>
* MIT Licensed
*/
var util = require('util')
, Validation = require('./Validation').Validation
, ErrorCodes = require('./ErrorCodes')
, BufferPool = require('./BufferPool')
, bufferUtil = require('./BufferUtil').BufferUtil
, PerMessageDeflate = require('./PerMessageDeflate');
/**
* HyBi Receiver implementation
*/
function Receiver (extensions,maxPayload) {
if (this instanceof Receiver === false) {
throw new TypeError("Classes can't be function-called");
}
if(typeof extensions==='number'){
maxPayload=extensions;
extensions={};
}
// memory pool for fragmented messages
var fragmentedPoolPrevUsed = -1;
this.fragmentedBufferPool = new BufferPool(1024, function(db, length) {
return db.used + length;
}, function(db) {
return fragmentedPoolPrevUsed = fragmentedPoolPrevUsed >= 0 ?
Math.ceil((fragmentedPoolPrevUsed + db.used) / 2) :
db.used;
});
// memory pool for unfragmented messages
var unfragmentedPoolPrevUsed = -1;
this.unfragmentedBufferPool = new BufferPool(1024, function(db, length) {
return db.used + length;
}, function(db) {
return unfragmentedPoolPrevUsed = unfragmentedPoolPrevUsed >= 0 ?
Math.ceil((unfragmentedPoolPrevUsed + db.used) / 2) :
db.used;
});
this.extensions = extensions || {};
this.maxPayload = maxPayload || 0;
this.currentPayloadLength = 0;
this.state = {
activeFragmentedOperation: null,
lastFragment: false,
masked: false,
opcode: 0,
fragmentedOperation: false
};
this.overflow = [];
this.headerBuffer = new Buffer(10);
this.expectOffset = 0;
this.expectBuffer = null;
this.expectHandler = null;
this.currentMessage = [];
this.currentMessageLength = 0;
this.messageHandlers = [];
this.expectHeader(2, this.processPacket);
this.dead = false;
this.processing = false;
this.onerror = function() {};
this.ontext = function() {};
this.onbinary = function() {};
this.onclose = function() {};
this.onping = function() {};
this.onpong = function() {};
}
module.exports = Receiver;
/**
* Add new data to the parser.
*
* @api public
*/
Receiver.prototype.add = function(data) {
if (this.dead) return;
var dataLength = data.length;
if (dataLength == 0) return;
if (this.expectBuffer == null) {
this.overflow.push(data);
return;
}
var toRead = Math.min(dataLength, this.expectBuffer.length - this.expectOffset);
fastCopy(toRead, data, this.expectBuffer, this.expectOffset);
this.expectOffset += toRead;
if (toRead < dataLength) {
this.overflow.push(data.slice(toRead));
}
while (this.expectBuffer && this.expectOffset == this.expectBuffer.length) {
var bufferForHandler = this.expectBuffer;
this.expectBuffer = null;
this.expectOffset = 0;
this.expectHandler.call(this, bufferForHandler);
}
};
/**
* Releases all resources used by the receiver.
*
* @api public
*/
Receiver.prototype.cleanup = function() {
this.dead = true;
this.overflow = null;
this.headerBuffer = null;
this.expectBuffer = null;
this.expectHandler = null;
this.unfragmentedBufferPool = null;
this.fragmentedBufferPool = null;
this.state = null;
this.currentMessage = null;
this.onerror = null;
this.ontext = null;
this.onbinary = null;
this.onclose = null;
this.onping = null;
this.onpong = null;
};
/**
* Waits for a certain amount of header bytes to be available, then fires a callback.
*
* @api private
*/
Receiver.prototype.expectHeader = function(length, handler) {
if (length == 0) {
handler(null);
return;
}
this.expectBuffer = this.headerBuffer.slice(this.expectOffset, this.expectOffset + length);
this.expectHandler = handler;
var toRead = length;
while (toRead > 0 && this.overflow.length > 0) {
var fromOverflow = this.overflow.pop();
if (toRead < fromOverflow.length) this.overflow.push(fromOverflow.slice(toRead));
var read = Math.min(fromOverflow.length, toRead);
fastCopy(read, fromOverflow, this.expectBuffer, this.expectOffset);
this.expectOffset += read;
toRead -= read;
}
};
/**
* Waits for a certain amount of data bytes to be available, then fires a callback.
*
* @api private
*/
Receiver.prototype.expectData = function(length, handler) {
if (length == 0) {
handler(null);
return;
}
this.expectBuffer = this.allocateFromPool(length, this.state.fragmentedOperation);
this.expectHandler = handler;
var toRead = length;
while (toRead > 0 && this.overflow.length > 0) {
var fromOverflow = this.overflow.pop();
if (toRead < fromOverflow.length) this.overflow.push(fromOverflow.slice(toRead));
var read = Math.min(fromOverflow.length, toRead);
fastCopy(read, fromOverflow, this.expectBuffer, this.expectOffset);
this.expectOffset += read;
toRead -= read;
}
};
/**
* Allocates memory from the buffer pool.
*
* @api private
*/
Receiver.prototype.allocateFromPool = function(length, isFragmented) {
return (isFragmented ? this.fragmentedBufferPool : this.unfragmentedBufferPool).get(length);
};
/**
* Start processing a new packet.
*
* @api private
*/
Receiver.prototype.processPacket = function (data) {
if (this.extensions[PerMessageDeflate.extensionName]) {
if ((data[0] & 0x30) != 0) {
this.error('reserved fields (2, 3) must be empty', 1002);
return;
}
} else {
if ((data[0] & 0x70) != 0) {
this.error('reserved fields must be empty', 1002);
return;
}
}
this.state.lastFragment = (data[0] & 0x80) == 0x80;
this.state.masked = (data[1] & 0x80) == 0x80;
var compressed = (data[0] & 0x40) == 0x40;
var opcode = data[0] & 0xf;
if (opcode === 0) {
if (compressed) {
this.error('continuation frame cannot have the Per-message Compressed bits', 1002);
return;
}
// continuation frame
this.state.fragmentedOperation = true;
this.state.opcode = this.state.activeFragmentedOperation;
if (!(this.state.opcode == 1 || this.state.opcode == 2)) {
this.error('continuation frame cannot follow current opcode', 1002);
return;
}
}
else {
if (opcode < 3 && this.state.activeFragmentedOperation != null) {
this.error('data frames after the initial data frame must have opcode 0', 1002);
return;
}
if (opcode >= 8 && compressed) {
this.error('control frames cannot have the Per-message Compressed bits', 1002);
return;
}
this.state.compressed = compressed;
this.state.opcode = opcode;
if (this.state.lastFragment === false) {
this.state.fragmentedOperation = true;
this.state.activeFragmentedOperation = opcode;
}
else this.state.fragmentedOperation = false;
}
var handler = opcodes[this.state.opcode];
if (typeof handler == 'undefined') this.error('no handler for opcode ' + this.state.opcode, 1002);
else {
handler.start.call(this, data);
}
};
/**
* Endprocessing a packet.
*
* @api private
*/
Receiver.prototype.endPacket = function() {
if (this.dead) return;
if (!this.state.fragmentedOperation) this.unfragmentedBufferPool.reset(true);
else if (this.state.lastFragment) this.fragmentedBufferPool.reset(true);
this.expectOffset = 0;
this.expectBuffer = null;
this.expectHandler = null;
if (this.state.lastFragment && this.state.opcode === this.state.activeFragmentedOperation) {
// end current fragmented operation
this.state.activeFragmentedOperation = null;
}
this.currentPayloadLength = 0;
this.state.lastFragment = false;
this.state.opcode = this.state.activeFragmentedOperation != null ? this.state.activeFragmentedOperation : 0;
this.state.masked = false;
this.expectHeader(2, this.processPacket);
};
/**
* Reset the parser state.
*
* @api private
*/
Receiver.prototype.reset = function() {
if (this.dead) return;
this.state = {
activeFragmentedOperation: null,
lastFragment: false,
masked: false,
opcode: 0,
fragmentedOperation: false
};
this.fragmentedBufferPool.reset(true);
this.unfragmentedBufferPool.reset(true);
this.expectOffset = 0;
this.expectBuffer = null;
this.expectHandler = null;
this.overflow = [];
this.currentMessage = [];
this.currentMessageLength = 0;
this.messageHandlers = [];
this.currentPayloadLength = 0;
};
/**
* Unmask received data.
*
* @api private
*/
Receiver.prototype.unmask = function (mask, buf, binary) {
if (mask != null && buf != null) bufferUtil.unmask(buf, mask);
if (binary) return buf;
return buf != null ? buf.toString('utf8') : '';
};
/**
* Handles an error
*
* @api private
*/
Receiver.prototype.error = function (reason, protocolErrorCode) {
if (this.dead) return;
this.reset();
if(typeof reason == 'string'){
this.onerror(new Error(reason), protocolErrorCode);
}
else if(reason.constructor == Error){
this.onerror(reason, protocolErrorCode);
}
else{
this.onerror(new Error("An error occured"),protocolErrorCode);
}
return this;
};
/**
* Execute message handler buffers
*
* @api private
*/
Receiver.prototype.flush = function() {
if (this.processing || this.dead) 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
*/
Receiver.prototype.applyExtensions = function(messageBuffer, fin, compressed, callback) {
var self = this;
if (compressed) {
this.extensions[PerMessageDeflate.extensionName].decompress(messageBuffer, fin, function(err, buffer) {
if (self.dead) return;
if (err) {
callback(new Error('invalid compressed data'));
return;
}
callback(null, buffer);
});
} else {
callback(null, messageBuffer);
}
};
/**
* Checks payload size, disconnects socket when it exceeds maxPayload
*
* @api private
*/
Receiver.prototype.maxPayloadExceeded = function(length) {
if (this.maxPayload=== undefined || this.maxPayload === null || this.maxPayload < 1) {
return false;
}
var fullLength = this.currentPayloadLength + length;
if (fullLength < this.maxPayload) {
this.currentPayloadLength = fullLength;
return false;
}
this.error('payload cannot exceed ' + this.maxPayload + ' bytes', 1009);
this.messageBuffer=[];
this.cleanup();
return true;
};
/**
* Buffer utilities
*/
function readUInt16BE(start) {
return (this[start]<<8) +
this[start+1];
}
function readUInt32BE(start) {
return (this[start]<<24) +
(this[start+1]<<16) +
(this[start+2]<<8) +
this[start+3];
}
function fastCopy(length, srcBuffer, dstBuffer, dstOffset) {
switch (length) {
default: srcBuffer.copy(dstBuffer, dstOffset, 0, length); break;
case 16: dstBuffer[dstOffset+15] = srcBuffer[15];
case 15: dstBuffer[dstOffset+14] = srcBuffer[14];
case 14: dstBuffer[dstOffset+13] = srcBuffer[13];
case 13: dstBuffer[dstOffset+12] = srcBuffer[12];
case 12: dstBuffer[dstOffset+11] = srcBuffer[11];
case 11: dstBuffer[dstOffset+10] = srcBuffer[10];
case 10: dstBuffer[dstOffset+9] = srcBuffer[9];
case 9: dstBuffer[dstOffset+8] = srcBuffer[8];
case 8: dstBuffer[dstOffset+7] = srcBuffer[7];
case 7: dstBuffer[dstOffset+6] = srcBuffer[6];
case 6: dstBuffer[dstOffset+5] = srcBuffer[5];
case 5: dstBuffer[dstOffset+4] = srcBuffer[4];
case 4: dstBuffer[dstOffset+3] = srcBuffer[3];
case 3: dstBuffer[dstOffset+2] = srcBuffer[2];
case 2: dstBuffer[dstOffset+1] = srcBuffer[1];
case 1: dstBuffer[dstOffset] = srcBuffer[0];
}
}
function clone(obj) {
var cloned = {};
for (var k in obj) {
if (obj.hasOwnProperty(k)) {
cloned[k] = obj[k];
}
}
return cloned;
}
/**
* Opcode handlers
*/
var opcodes = {
// text
'1': {
start: function(data) {
var self = this;
// decode length
var firstLength = data[1] & 0x7f;
if (firstLength < 126) {
if (self.maxPayloadExceeded(firstLength)){
self.error('Maximumpayload exceeded in compressed text message. Aborting...', 1009);
return;
}
opcodes['1'].getData.call(self, firstLength);
}
else if (firstLength == 126) {
self.expectHeader(2, function(data) {
var length = readUInt16BE.call(data, 0);
if (self.maxPayloadExceeded(length)){
self.error('Maximumpayload exceeded in compressed text message. Aborting...', 1009);
return;
}
opcodes['1'].getData.call(self, length);
});
}
else if (firstLength == 127) {
self.expectHeader(8, function(data) {
if (readUInt32BE.call(data, 0) != 0) {
self.error('packets with length spanning more than 32 bit is currently not supported', 1008);
return;
}
var length = readUInt32BE.call(data, 4);
if (self.maxPayloadExceeded(length)){
self.error('Maximumpayload exceeded in compressed text message. Aborting...', 1009);
return;
}
opcodes['1'].getData.call(self, readUInt32BE.call(data, 4));
});
}
},
getData: function(length) {
var self = this;
if (self.state.masked) {
self.expectHeader(4, function(data) {
var mask = data;
self.expectData(length, function(data) {
opcodes['1'].finish.call(self, mask, data);
});
});
}
else {
self.expectData(length, function(data) {
opcodes['1'].finish.call(self, null, data);
});
}
},
finish: function(mask, data) {
var self = this;
var packet = this.unmask(mask, data, true) || new Buffer(0);
var state = clone(this.state);
this.messageHandlers.push(function(callback) {
self.applyExtensions(packet, state.lastFragment, state.compressed, function(err, buffer) {
if (err) {
if(err.type===1009){
return self.error('Maximumpayload exceeded in compressed text message. Aborting...', 1009);
}
return self.error(err.message, 1007);
}
if (buffer != null) {
if( self.maxPayload==0 || (self.maxPayload > 0 && (self.currentMessageLength + buffer.length) < self.maxPayload) ){
self.currentMessage.push(buffer);
}
else{
self.currentMessage=null;
self.currentMessage = [];
self.currentMessageLength = 0;
self.error(new Error('Maximum payload exceeded. maxPayload: '+self.maxPayload), 1009);
return;
}
self.currentMessageLength += buffer.length;
}
if (state.lastFragment) {
var messageBuffer = Buffer.concat(self.currentMessage);
self.currentMessage = [];
self.currentMessageLength = 0;
if (!Validation.isValidUTF8(messageBuffer)) {
self.error('invalid utf8 sequence', 1007);
return;
}
self.ontext(messageBuffer.toString('utf8'), {masked: state.masked, buffer: messageBuffer});
}
callback();
});
});
this.flush();
this.endPacket();
}
},
// binary
'2': {
start: function(data) {
var self = this;
// decode length
var firstLength = data[1] & 0x7f;
if (firstLength < 126) {
if (self.maxPayloadExceeded(firstLength)){
self.error('Max payload exceeded in compressed text message. Aborting...', 1009);
return;
}
opcodes['2'].getData.call(self, firstLength);
}
else if (firstLength == 126) {
self.expectHeader(2, function(data) {
var length = readUInt16BE.call(data, 0);
if (self.maxPayloadExceeded(length)){
self.error('Max payload exceeded in compressed text message. Aborting...', 1009);
return;
}
opcodes['2'].getData.call(self, length);
});
}
else if (firstLength == 127) {
self.expectHeader(8, function(data) {
if (readUInt32BE.call(data, 0) != 0) {
self.error('packets with length spanning more than 32 bit is currently not supported', 1008);
return;
}
var length = readUInt32BE.call(data, 4, true);
if (self.maxPayloadExceeded(length)){
self.error('Max payload exceeded in compressed text message. Aborting...', 1009);
return;
}
opcodes['2'].getData.call(self, length);
});
}
},
getData: function(length) {
var self = this;
if (self.state.masked) {
self.expectHeader(4, function(data) {
var mask = data;
self.expectData(length, function(data) {
opcodes['2'].finish.call(self, mask, data);
});
});
}
else {
self.expectData(length, function(data) {
opcodes['2'].finish.call(self, null, data);
});
}
},
finish: function(mask, data) {
var self = this;
var packet = this.unmask(mask, data, true) || new Buffer(0);
var state = clone(this.state);
this.messageHandlers.push(function(callback) {
self.applyExtensions(packet, state.lastFragment, state.compressed, function(err, buffer) {
if (err) {
if(err.type===1009){
return self.error('Max payload exceeded in compressed binary message. Aborting...', 1009);
}
return self.error(err.message, 1007);
}
if (buffer != null) {
if( self.maxPayload==0 || (self.maxPayload > 0 && (self.currentMessageLength + buffer.length) < self.maxPayload) ){
self.currentMessage.push(buffer);
}
else{
self.currentMessage=null;
self.currentMessage = [];
self.currentMessageLength = 0;
self.error(new Error('Maximum payload exceeded'), 1009);
return;
}
self.currentMessageLength += buffer.length;
}
if (state.lastFragment) {
var messageBuffer = Buffer.concat(self.currentMessage);
self.currentMessage = [];
self.currentMessageLength = 0;
self.onbinary(messageBuffer, {masked: state.masked, buffer: messageBuffer});
}
callback();
});
});
this.flush();
this.endPacket();
}
},
// close
'8': {
start: function(data) {
var self = this;
if (self.state.lastFragment == false) {
self.error('fragmented close is not supported', 1002);
return;
}
// decode length
var firstLength = data[1] & 0x7f;
if (firstLength < 126) {
opcodes['8'].getData.call(self, firstLength);
}
else {
self.error('control frames cannot have more than 125 bytes of data', 1002);
}
},
getData: function(length) {
var self = this;
if (self.state.masked) {
self.expectHeader(4, function(data) {
var mask = data;
self.expectData(length, function(data) {
opcodes['8'].finish.call(self, mask, data);
});
});
}
else {
self.expectData(length, function(data) {
opcodes['8'].finish.call(self, null, data);
});
}
},
finish: function(mask, data) {
var self = this;
data = self.unmask(mask, data, true);
var state = clone(this.state);
this.messageHandlers.push(function() {
if (data && data.length == 1) {
self.error('close packets with data must be at least two bytes long', 1002);
return;
}
var code = data && data.length > 1 ? readUInt16BE.call(data, 0) : 1000;
if (!ErrorCodes.isValidErrorCode(code)) {
self.error('invalid error code', 1002);
return;
}
var message = '';
if (data && data.length > 2) {
var messageBuffer = data.slice(2);
if (!Validation.isValidUTF8(messageBuffer)) {
self.error('invalid utf8 sequence', 1007);
return;
}
message = messageBuffer.toString('utf8');
}
self.onclose(code, message, {masked: state.masked});
self.reset();
});
this.flush();
},
},
// ping
'9': {
start: function(data) {
var self = this;
if (self.state.lastFragment == false) {
self.error('fragmented ping is not supported', 1002);
return;
}
// decode length
var firstLength = data[1] & 0x7f;
if (firstLength < 126) {
opcodes['9'].getData.call(self, firstLength);
}
else {
self.error('control frames cannot have more than 125 bytes of data', 1002);
}
},
getData: function(length) {
var self = this;
if (self.state.masked) {
self.expectHeader(4, function(data) {
var mask = data;
self.expectData(length, function(data) {
opcodes['9'].finish.call(self, mask, data);
});
});
}
else {
self.expectData(length, function(data) {
opcodes['9'].finish.call(self, null, data);
});
}
},
finish: function(mask, data) {
var self = this;
data = this.unmask(mask, data, true);
var state = clone(this.state);
this.messageHandlers.push(function(callback) {
self.onping(data, {masked: state.masked, binary: true});
callback();
});
this.flush();
this.endPacket();
}
},
// pong
'10': {
start: function(data) {
var self = this;
if (self.state.lastFragment == false) {
self.error('fragmented pong is not supported', 1002);
return;
}
// decode length
var firstLength = data[1] & 0x7f;
if (firstLength < 126) {
opcodes['10'].getData.call(self, firstLength);
}
else {
self.error('control frames cannot have more than 125 bytes of data', 1002);
}
},
getData: function(length) {
var self = this;
if (this.state.masked) {
this.expectHeader(4, function(data) {
var mask = data;
self.expectData(length, function(data) {
opcodes['10'].finish.call(self, mask, data);
});
});
}
else {
this.expectData(length, function(data) {
opcodes['10'].finish.call(self, null, data);
});
}
},
finish: function(mask, data) {
var self = this;
data = self.unmask(mask, data, true);
var state = clone(this.state);
this.messageHandlers.push(function(callback) {
self.onpong(data, {masked: state.masked, binary: true});
callback();
});
this.flush();
this.endPacket();
}
}
}