Haha-Yes/node_modules/ws/lib/receiver.js
2018-09-06 15:02:53 +02:00

589 lines
13 KiB
JavaScript

'use strict';
const safeBuffer = require('safe-buffer');
const PerMessageDeflate = require('./permessage-deflate');
const bufferUtil = require('./buffer-util');
const validation = require('./validation');
const constants = require('./constants');
const Buffer = safeBuffer.Buffer;
const GET_INFO = 0;
const GET_PAYLOAD_LENGTH_16 = 1;
const GET_PAYLOAD_LENGTH_64 = 2;
const GET_MASK = 3;
const GET_DATA = 4;
const INFLATING = 5;
/**
* HyBi Receiver implementation.
*/
class Receiver {
/**
* Creates a Receiver instance.
*
* @param {Object} extensions An object containing the negotiated extensions
* @param {Number} maxPayload The maximum allowed message length
* @param {String} binaryType The type for binary data
*/
constructor (extensions, maxPayload, binaryType) {
this._binaryType = binaryType || constants.BINARY_TYPES[0];
this._extensions = extensions || {};
this._maxPayload = maxPayload | 0;
this._bufferedBytes = 0;
this._buffers = [];
this._compressed = false;
this._payloadLength = 0;
this._fragmented = 0;
this._masked = false;
this._fin = false;
this._mask = null;
this._opcode = 0;
this._totalPayloadLength = 0;
this._messageLength = 0;
this._fragments = [];
this._cleanupCallback = null;
this._isCleaningUp = false;
this._hadError = false;
this._loop = false;
this.add = this.add.bind(this);
this.onmessage = null;
this.onclose = null;
this.onerror = null;
this.onping = null;
this.onpong = null;
this._state = GET_INFO;
}
/**
* Consumes `n` bytes from the buffered data, calls `cleanup` if necessary.
*
* @param {Number} n The number of bytes to consume
* @return {(Buffer|null)} The consumed bytes or `null` if `n` bytes are not
* available
* @private
*/
consume (n) {
if (this._bufferedBytes < n) {
this._loop = false;
if (this._isCleaningUp) this.cleanup(this._cleanupCallback);
return null;
}
this._bufferedBytes -= n;
if (n === this._buffers[0].length) return this._buffers.shift();
if (n < this._buffers[0].length) {
const buf = this._buffers[0];
this._buffers[0] = buf.slice(n);
return buf.slice(0, n);
}
const dst = Buffer.allocUnsafe(n);
do {
const buf = this._buffers[0];
if (n >= buf.length) {
this._buffers.shift().copy(dst, dst.length - n);
} else {
buf.copy(dst, dst.length - n, 0, n);
this._buffers[0] = buf.slice(n);
}
n -= buf.length;
} while (n > 0);
return dst;
}
/**
* Adds new data to the parser.
*
* @param {Buffer} chunk A chunk of data
* @public
*/
add (chunk) {
this._bufferedBytes += chunk.length;
this._buffers.push(chunk);
this.startLoop();
}
/**
* Starts the parsing loop.
*
* @private
*/
startLoop () {
this._loop = true;
do {
switch (this._state) {
case GET_INFO:
this.getInfo();
break;
case GET_PAYLOAD_LENGTH_16:
this.getPayloadLength16();
break;
case GET_PAYLOAD_LENGTH_64:
this.getPayloadLength64();
break;
case GET_MASK:
this.getMask();
break;
case GET_DATA:
this.getData();
break;
default: // `INFLATING`
this._loop = false;
}
} while (this._loop);
}
/**
* Reads the first two bytes of a frame.
*
* @private
*/
getInfo () {
const buf = this.consume(2);
if (buf === null) return;
if ((buf[0] & 0x30) !== 0x00) {
this.error(
new RangeError('Invalid WebSocket frame: RSV2 and RSV3 must be clear'),
1002
);
return;
}
const compressed = (buf[0] & 0x40) === 0x40;
if (compressed && !this._extensions[PerMessageDeflate.extensionName]) {
this.error(
new RangeError('Invalid WebSocket frame: RSV1 must be clear'),
1002
);
return;
}
this._fin = (buf[0] & 0x80) === 0x80;
this._opcode = buf[0] & 0x0f;
this._payloadLength = buf[1] & 0x7f;
if (this._opcode === 0x00) {
if (compressed) {
this.error(
new RangeError('Invalid WebSocket frame: RSV1 must be clear'),
1002
);
return;
}
if (!this._fragmented) {
this.error(
new RangeError('Invalid WebSocket frame: invalid opcode 0'),
1002
);
return;
} else {
this._opcode = this._fragmented;
}
} else if (this._opcode === 0x01 || this._opcode === 0x02) {
if (this._fragmented) {
this.error(
new RangeError(
`Invalid WebSocket frame: invalid opcode ${this._opcode}`
),
1002
);
return;
}
this._compressed = compressed;
} else if (this._opcode > 0x07 && this._opcode < 0x0b) {
if (!this._fin) {
this.error(
new RangeError('Invalid WebSocket frame: FIN must be set'),
1002
);
return;
}
if (compressed) {
this.error(
new RangeError('Invalid WebSocket frame: RSV1 must be clear'),
1002
);
return;
}
if (this._payloadLength > 0x7d) {
this.error(
new RangeError(
`Invalid WebSocket frame: invalid payload length ` +
`${this._payloadLength}`
),
1002
);
return;
}
} else {
this.error(
new RangeError(
`Invalid WebSocket frame: invalid opcode ${this._opcode}`
),
1002
);
return;
}
if (!this._fin && !this._fragmented) this._fragmented = this._opcode;
this._masked = (buf[1] & 0x80) === 0x80;
if (this._payloadLength === 126) this._state = GET_PAYLOAD_LENGTH_16;
else if (this._payloadLength === 127) this._state = GET_PAYLOAD_LENGTH_64;
else this.haveLength();
}
/**
* Gets extended payload length (7+16).
*
* @private
*/
getPayloadLength16 () {
const buf = this.consume(2);
if (buf === null) return;
this._payloadLength = buf.readUInt16BE(0, true);
this.haveLength();
}
/**
* Gets extended payload length (7+64).
*
* @private
*/
getPayloadLength64 () {
const buf = this.consume(8);
if (buf === null) return;
const num = buf.readUInt32BE(0, true);
//
// The maximum safe integer in JavaScript is 2^53 - 1. An error is returned
// if payload length is greater than this number.
//
if (num > Math.pow(2, 53 - 32) - 1) {
this.error(
new RangeError(
'Unsupported WebSocket frame: payload length > 2^53 - 1'
),
1009
);
return;
}
this._payloadLength = num * Math.pow(2, 32) + buf.readUInt32BE(4, true);
this.haveLength();
}
/**
* Payload length has been read.
*
* @private
*/
haveLength () {
if (this._opcode < 0x08 && this.maxPayloadExceeded(this._payloadLength)) {
return;
}
if (this._masked) this._state = GET_MASK;
else this._state = GET_DATA;
}
/**
* Reads mask bytes.
*
* @private
*/
getMask () {
this._mask = this.consume(4);
if (this._mask === null) return;
this._state = GET_DATA;
}
/**
* Reads data bytes.
*
* @private
*/
getData () {
var data = constants.EMPTY_BUFFER;
if (this._payloadLength) {
data = this.consume(this._payloadLength);
if (data === null) return;
if (this._masked) bufferUtil.unmask(data, this._mask);
}
if (this._opcode > 0x07) {
this.controlMessage(data);
} else if (this._compressed) {
this._state = INFLATING;
this.decompress(data);
} else if (this.pushFragment(data)) {
this.dataMessage();
}
}
/**
* Decompresses data.
*
* @param {Buffer} data Compressed data
* @private
*/
decompress (data) {
const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
perMessageDeflate.decompress(data, this._fin, (err, buf) => {
if (err) {
this.error(err, err.closeCode === 1009 ? 1009 : 1007);
return;
}
if (this.pushFragment(buf)) this.dataMessage();
this.startLoop();
});
}
/**
* Handles a data message.
*
* @private
*/
dataMessage () {
if (this._fin) {
const messageLength = this._messageLength;
const fragments = this._fragments;
this._totalPayloadLength = 0;
this._messageLength = 0;
this._fragmented = 0;
this._fragments = [];
if (this._opcode === 2) {
var data;
if (this._binaryType === 'nodebuffer') {
data = toBuffer(fragments, messageLength);
} else if (this._binaryType === 'arraybuffer') {
data = toArrayBuffer(toBuffer(fragments, messageLength));
} else {
data = fragments;
}
this.onmessage(data);
} else {
const buf = toBuffer(fragments, messageLength);
if (!validation.isValidUTF8(buf)) {
this.error(
new Error('Invalid WebSocket frame: invalid UTF-8 sequence'),
1007
);
return;
}
this.onmessage(buf.toString());
}
}
this._state = GET_INFO;
}
/**
* Handles a control message.
*
* @param {Buffer} data Data to handle
* @private
*/
controlMessage (data) {
if (this._opcode === 0x08) {
if (data.length === 0) {
this._loop = false;
this.onclose(1005, '');
this.cleanup(this._cleanupCallback);
} else if (data.length === 1) {
this.error(
new RangeError('Invalid WebSocket frame: invalid payload length 1'),
1002
);
} else {
const code = data.readUInt16BE(0, true);
if (!validation.isValidStatusCode(code)) {
this.error(
new RangeError(
`Invalid WebSocket frame: invalid status code ${code}`
),
1002
);
return;
}
const buf = data.slice(2);
if (!validation.isValidUTF8(buf)) {
this.error(
new Error('Invalid WebSocket frame: invalid UTF-8 sequence'),
1007
);
return;
}
this._loop = false;
this.onclose(code, buf.toString());
this.cleanup(this._cleanupCallback);
}
return;
}
if (this._opcode === 0x09) this.onping(data);
else this.onpong(data);
this._state = GET_INFO;
}
/**
* Handles an error.
*
* @param {Error} err The error
* @param {Number} code Close code
* @private
*/
error (err, code) {
this._hadError = true;
this._loop = false;
this.onerror(err, code);
this.cleanup(this._cleanupCallback);
}
/**
* Checks payload size, disconnects socket when it exceeds `maxPayload`.
*
* @param {Number} length Payload length
* @private
*/
maxPayloadExceeded (length) {
if (length === 0 || this._maxPayload < 1) return false;
const fullLength = this._totalPayloadLength + length;
if (fullLength <= this._maxPayload) {
this._totalPayloadLength = fullLength;
return false;
}
this.error(new RangeError('Max payload size exceeded'), 1009);
return true;
}
/**
* Appends a fragment in the fragments array after checking that the sum of
* fragment lengths does not exceed `maxPayload`.
*
* @param {Buffer} fragment The fragment to add
* @return {Boolean} `true` if `maxPayload` is not exceeded, else `false`
* @private
*/
pushFragment (fragment) {
if (fragment.length === 0) return true;
const totalLength = this._messageLength + fragment.length;
if (this._maxPayload < 1 || totalLength <= this._maxPayload) {
this._messageLength = totalLength;
this._fragments.push(fragment);
return true;
}
this.error(new RangeError('Max payload size exceeded'), 1009);
return false;
}
/**
* Releases resources used by the receiver.
*
* @param {Function} cb Callback
* @public
*/
cleanup (cb) {
if (this._extensions === null) {
if (cb) cb();
return;
}
if (!this._hadError && (this._loop || this._state === INFLATING)) {
this._cleanupCallback = cb;
this._isCleaningUp = true;
return;
}
this._extensions = null;
this._fragments = null;
this._buffers = null;
this._mask = null;
this._cleanupCallback = null;
this.onmessage = null;
this.onclose = null;
this.onerror = null;
this.onping = null;
this.onpong = null;
if (cb) cb();
}
}
module.exports = Receiver;
/**
* Makes a buffer from a list of fragments.
*
* @param {Buffer[]} fragments The list of fragments composing the message
* @param {Number} messageLength The length of the message
* @return {Buffer}
* @private
*/
function toBuffer (fragments, messageLength) {
if (fragments.length === 1) return fragments[0];
if (fragments.length > 1) return bufferUtil.concat(fragments, messageLength);
return constants.EMPTY_BUFFER;
}
/**
* Converts a buffer to an `ArrayBuffer`.
*
* @param {Buffer} The buffer to convert
* @return {ArrayBuffer} Converted buffer
*/
function toArrayBuffer (buf) {
if (buf.byteOffset === 0 && buf.byteLength === buf.buffer.byteLength) {
return buf.buffer;
}
return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
}