'use strict';
var Buffer = require('safe-buffer').Buffer,
crypto = require('crypto'),
util = require('util'),
Extensions = require('websocket-extensions'),
Base = require('./base'),
Frame = require('./hybi/frame'),
Message = require('./hybi/message');
var Hybi = function(request, url, options) {
Base.apply(this, arguments);
this._extensions = new Extensions();
this._stage = 0;
this._masking = this._options.masking;
this._protocols = this._options.protocols || [];
this._requireMasking = this._options.requireMasking;
this._pingCallbacks = {};
if (typeof this._protocols === 'string')
this._protocols = this._protocols.split(/ *, */);
if (!this._request) return;
var protos = this._request.headers['sec-websocket-protocol'],
supported = this._protocols;
if (protos !== undefined) {
if (typeof protos === 'string') protos = protos.split(/ *, */);
this.protocol = protos.filter(function(p) { return supported.indexOf(p) >= 0 })[0];
}
this.version = 'hybi-' + Hybi.VERSION;
};
util.inherits(Hybi, Base);
Hybi.VERSION = '13';
Hybi.mask = function(payload, mask, offset) {
if (!mask || mask.length === 0) return payload;
offset = offset || 0;
for (var i = 0, n = payload.length - offset; i < n; i++) {
payload[offset + i] = payload[offset + i] ^ mask[i % 4];
}
return payload;
};
Hybi.generateAccept = function(key) {
var sha1 = crypto.createHash('sha1');
sha1.update(key + Hybi.GUID);
return sha1.digest('base64');
};
Hybi.GUID = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11';
var instance = {
FIN: 0x80,
MASK: 0x80,
RSV1: 0x40,
RSV2: 0x20,
RSV3: 0x10,
OPCODE: 0x0F,
LENGTH: 0x7F,
OPCODES: {
continuation: 0,
text: 1,
binary: 2,
close: 8,
ping: 9,
pong: 10
},
OPCODE_CODES: [0, 1, 2, 8, 9, 10],
MESSAGE_OPCODES: [0, 1, 2],
OPENING_OPCODES: [1, 2],
ERRORS: {
normal_closure: 1000,
going_away: 1001,
protocol_error: 1002,
unacceptable: 1003,
encoding_error: 1007,
policy_violation: 1008,
too_large: 1009,
extension_error: 1010,
unexpected_condition: 1011
},
ERROR_CODES: [1000, 1001, 1002, 1003, 1007, 1008, 1009, 1010, 1011],
DEFAULT_ERROR_CODE: 1000,
MIN_RESERVED_ERROR: 3000,
MAX_RESERVED_ERROR: 4999,
// http://www.w3.org/International/questions/qa-forms-utf-8.en.php
UTF8_MATCH: /^([\x00-\x7F]|[\xC2-\xDF][\x80-\xBF]|\xE0[\xA0-\xBF][\x80-\xBF]|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}|\xED[\x80-\x9F][\x80-\xBF]|\xF0[\x90-\xBF][\x80-\xBF]{2}|[\xF1-\xF3][\x80-\xBF]{3}|\xF4[\x80-\x8F][\x80-\xBF]{2})*$/,
addExtension: function(extension) {
this._extensions.add(extension);
return true;
},
parse: function(chunk) {
this._reader.put(chunk);
var buffer = true;
while (buffer) {
switch (this._stage) {
case 0:
buffer = this._reader.read(1);
if (buffer) this._parseOpcode(buffer[0]);
break;
case 1:
buffer = this._reader.read(1);
if (buffer) this._parseLength(buffer[0]);
break;
case 2:
buffer = this._reader.read(this._frame.lengthBytes);
if (buffer) this._parseExtendedLength(buffer);
break;
case 3:
buffer = this._reader.read(4);
if (buffer) {
this._stage = 4;
this._frame.maskingKey = buffer;
}
break;
case 4:
buffer = this._reader.read(this._frame.length);
if (buffer) {
this._stage = 0;
this._emitFrame(buffer);
}
break;
default:
buffer = null;
}
}
},
text: function(message) {
if (this.readyState > 1) return false;
return this.frame(message, 'text');
},
binary: function(message) {
if (this.readyState > 1) return false;
return this.frame(message, 'binary');
},
ping: function(message, callback) {
if (this.readyState > 1) return false;
message = message || '';
if (callback) this._pingCallbacks[message] = callback;
return this.frame(message, 'ping');
},
pong: function(message) {
if (this.readyState > 1) return false;
message = message ||'';
return this.frame(message, 'pong');
},
close: function(reason, code) {
reason = reason || '';
code = code || this.ERRORS.normal_closure;
if (this.readyState <= 0) {
this.readyState = 3;
this.emit('close', new Base.CloseEvent(code, reason));
return true;
} else if (this.readyState === 1) {
this.readyState = 2;
this._extensions.close(function() { this.frame(reason, 'close', code) }, this);
return true;
} else {
return false;
}
},
frame: function(buffer, type, code) {
if (this.readyState <= 0) return this._queue([buffer, type, code]);
if (this.readyState > 2) return false;
if (buffer instanceof Array) buffer = Buffer.from(buffer);
if (typeof buffer === 'number') buffer = buffer.toString();
var message = new Message(),
isText = (typeof buffer === 'string'),
payload, copy;
message.rsv1 = message.rsv2 = message.rsv3 = false;
message.opcode = this.OPCODES[type || (isText ? 'text' : 'binary')];
payload = isText ? Buffer.from(buffer, 'utf8') : buffer;
if (code) {
copy = payload;
payload = Buffer.allocUnsafe(2 + copy.length);
payload.writeUInt16BE(code, 0);
copy.copy(payload, 2);
}
message.data = payload;
var onMessageReady = function(message) {
var frame = new Frame();
frame.final = true;
frame.rsv1 = message.rsv1;
frame.rsv2 = message.rsv2;
frame.rsv3 = message.rsv3;
frame.opcode = message.opcode;
frame.masked = !!this._masking;
frame.length = message.data.length;
frame.payload = message.data;
if (frame.masked) frame.maskingKey = crypto.randomBytes(4);
this._sendFrame(frame);
};
if (this.MESSAGE_OPCODES.indexOf(message.opcode) >= 0)
this._extensions.processOutgoingMessage(message, function(error, message) {
if (error) return this._fail('extension_error', error.message);
onMessageReady.call(this, message);
}, this);
else
onMessageReady.call(this, message);
return true;
},
_sendFrame: function(frame) {
var length = frame.length,
header = (length <= 125) ? 2 : (length <= 65535 ? 4 : 10),
offset = header + (frame.masked ? 4 : 0),
buffer = Buffer.allocUnsafe(offset + length),
masked = frame.masked ? this.MASK : 0;
buffer[0] = (frame.final ? this.FIN : 0) |
(frame.rsv1 ? this.RSV1 : 0) |
(frame.rsv2 ? this.RSV2 : 0) |
(frame.rsv3 ? this.RSV3 : 0) |
frame.opcode;
if (length <= 125) {
buffer[1] = masked | length;
} else if (length <= 65535) {
buffer[1] = masked | 126;
buffer.writeUInt16BE(length, 2);
} else {
buffer[1] = masked | 127;
buffer.writeUInt32BE(Math.floor(length / 0x100000000), 2);
buffer.writeUInt32BE(length % 0x100000000, 6);
}
frame.payload.copy(buffer, offset);
if (frame.masked) {
frame.maskingKey.copy(buffer, header);
Hybi.mask(buffer, frame.maskingKey, offset);
}
this._write(buffer);
},
_handshakeResponse: function() {
var secKey = this._request.headers['sec-websocket-key'],
version = this._request.headers['sec-websocket-version'];
if (version !== Hybi.VERSION)
throw new Error('Unsupported WebSocket version: ' + version);
if (typeof secKey !== 'string')
throw new Error('Missing handshake request header: Sec-WebSocket-Key');
this._headers.set('Upgrade', 'websocket');
this._headers.set('Connection', 'Upgrade');
this._headers.set('Sec-WebSocket-Accept', Hybi.generateAccept(secKey));
if (this.protocol) this._headers.set('Sec-WebSocket-Protocol', this.protocol);
var extensions = this._extensions.generateResponse(this._request.headers['sec-websocket-extensions']);
if (extensions) this._headers.set('Sec-WebSocket-Extensions', extensions);
var start = 'HTTP/1.1 101 Switching Protocols',
headers = [start, this._headers.toString(), ''];
return Buffer.from(headers.join('\r\n'), 'utf8');
},
_shutdown: function(code, reason, error) {
delete this._frame;
delete this._message;
this._stage = 5;
var sendCloseFrame = (this.readyState === 1);
this.readyState = 2;
this._extensions.close(function() {
if (sendCloseFrame) this.frame(reason, 'close', code);
this.readyState = 3;
if (error) this.emit('error', new Error(reason));
this.emit('close', new Base.CloseEvent(code, reason));
}, this);
},
_fail: function(type, message) {
if (this.readyState > 1) return;
this._shutdown(this.ERRORS[type], message, true);
},
_parseOpcode: function(octet) {
var rsvs = [this.RSV1, this.RSV2, this.RSV3].map(function(rsv) {
return (octet & rsv) === rsv;
});
var frame = this._frame = new Frame();
frame.final = (octet & this.FIN) === this.FIN;
frame.rsv1 = rsvs[0];
frame.rsv2 = rsvs[1];
frame.rsv3 = rsvs[2];
frame.opcode = (octet & this.OPCODE);
this._stage = 1;
if (!this._extensions.validFrameRsv(frame))
return this._fail('protocol_error',
'One or more reserved bits are on: reserved1 = ' + (frame.rsv1 ? 1 : 0) +
', reserved2 = ' + (frame.rsv2 ? 1 : 0) +
', reserved3 = ' + (frame.rsv3 ? 1 : 0));
if (this.OPCODE_CODES.indexOf(frame.opcode) < 0)
return this._fail('protocol_error', 'Unrecognized frame opcode: ' + frame.opcode);
if (this.MESSAGE_OPCODES.indexOf(frame.opcode) < 0 && !frame.final)
return this._fail('protocol_error', 'Received fragmented control frame: opcode = ' + frame.opcode);
if (this._message && this.OPENING_OPCODES.indexOf(frame.opcode) >= 0)
return this._fail('protocol_error', 'Received new data frame but previous continuous frame is unfinished');
},
_parseLength: function(octet) {
var frame = this._frame;
frame.masked = (octet & this.MASK) === this.MASK;
frame.length = (octet & this.LENGTH);
if (frame.length >= 0 && frame.length <= 125) {
this._stage = frame.masked ? 3 : 4;
if (!this._checkFrameLength()) return;
} else {
this._stage = 2;
frame.lengthBytes = (frame.length === 126 ? 2 : 8);
}
if (this._requireMasking && !frame.masked)
return this._fail('unacceptable', 'Received unmasked frame but masking is required');
},
_parseExtendedLength: function(buffer) {
var frame = this._frame;
frame.length = this._readUInt(buffer);
this._stage = frame.masked ? 3 : 4;
if (this.MESSAGE_OPCODES.indexOf(frame.opcode) < 0 && frame.length > 125)
return this._fail('protocol_error', 'Received control frame having too long payload: ' + frame.length);
if (!this._checkFrameLength()) return;
},
_checkFrameLength: function() {
var length = this._message ? this._message.length : 0;
if (length + this._frame.length > this._maxLength) {
this._fail('too_large', 'WebSocket frame length too large');
return false;
} else {
return true;
}
},
_emitFrame: function(buffer) {
var frame = this._frame,
payload = frame.payload = Hybi.mask(buffer, frame.maskingKey),
opcode = frame.opcode,
message,
code, reason,
callbacks, callback;
delete this._frame;
if (opcode === this.OPCODES.continuation) {
if (!this._message) return this._fail('protocol_error', 'Received unexpected continuation frame');
this._message.pushFrame(frame);
}
if (opcode === this.OPCODES.text || opcode === this.OPCODES.binary) {
this._message = new Message();
this._message.pushFrame(frame);
}
if (frame.final && this.MESSAGE_OPCODES.indexOf(opcode) >= 0)
return this._emitMessage(this._message);
if (opcode === this.OPCODES.close) {
code = (payload.length >= 2) ? payload.readUInt16BE(0) : null;
reason = (payload.length > 2) ? this._encode(payload.slice(2)) : null;
if (!(payload.length === 0) &&
!(code !== null && code >= this.MIN_RESERVED_ERROR && code <= this.MAX_RESERVED_ERROR) &&
this.ERROR_CODES.indexOf(code) < 0)
code = this.ERRORS.protocol_error;
if (payload.length > 125 || (payload.length > 2 && !reason))
code = this.ERRORS.protocol_error;
this._shutdown(code || this.DEFAULT_ERROR_CODE, reason || '');
}
if (opcode === this.OPCODES.ping) {
this.frame(payload, 'pong');
this.emit('ping', new Base.PingEvent(payload.toString()))
}
if (opcode === this.OPCODES.pong) {
callbacks = this._pingCallbacks;
message = this._encode(payload);
callback = callbacks[message];
delete callbacks[message];
if (callback) callback()
this.emit('pong', new Base.PongEvent(payload.toString()))
}
},
_emitMessage: function(message) {
var message = this._message;
message.read();
delete this._message;
this._extensions.processIncomingMessage(message, function(error, message) {
if (error) return this._fail('extension_error', error.message);
var payload = message.data;
if (message.opcode === this.OPCODES.text) payload = this._encode(payload);
if (payload === null)
return this._fail('encoding_error', 'Could not decode a text frame as UTF-8');
else
this.emit('message', new Base.MessageEvent(payload));
}, this);
},
_encode: function(buffer) {
try {
var string = buffer.toString('binary', 0, buffer.length);
if (!this.UTF8_MATCH.test(string)) return null;
} catch (e) {}
return buffer.toString('utf8', 0, buffer.length);
},
_readUInt: function(buffer) {
if (buffer.length === 2) return buffer.readUInt16BE(0);
return buffer.readUInt32BE(0) * 0x100000000 +
buffer.readUInt32BE(4);
}
};
for (var key in instance)
Hybi.prototype[key] = instance[key];
module.exports = Hybi;