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setup-python/node_modules/ws/lib/receiver.js
Danny McCormick 39c08a0eaa Initial pass
2019-06-26 21:12:00 -04:00

513 lines
12 KiB
JavaScript

'use strict';
const stream = require('stream');
const PerMessageDeflate = require('./permessage-deflate');
const bufferUtil = require('./buffer-util');
const validation = require('./validation');
const constants = require('./constants');
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.
*
* @extends stream.Writable
*/
class Receiver extends stream.Writable {
/**
* Creates a Receiver instance.
*
* @param {String} binaryType The type for binary data
* @param {Object} extensions An object containing the negotiated extensions
* @param {Number} maxPayload The maximum allowed message length
*/
constructor (binaryType, extensions, maxPayload) {
super();
this._binaryType = binaryType || constants.BINARY_TYPES[0];
this[constants.kWebSocket] = undefined;
this._extensions = extensions || {};
this._maxPayload = maxPayload | 0;
this._bufferedBytes = 0;
this._buffers = [];
this._compressed = false;
this._payloadLength = 0;
this._mask = undefined;
this._fragmented = 0;
this._masked = false;
this._fin = false;
this._opcode = 0;
this._totalPayloadLength = 0;
this._messageLength = 0;
this._fragments = [];
this._state = GET_INFO;
this._loop = false;
}
/**
* Implements `Writable.prototype._write()`.
*
* @param {Buffer} chunk The chunk of data to write
* @param {String} encoding The character encoding of `chunk`
* @param {Function} cb Callback
*/
_write (chunk, encoding, cb) {
if (this._opcode === 0x08) return cb();
this._bufferedBytes += chunk.length;
this._buffers.push(chunk);
this.startLoop(cb);
}
/**
* Consumes `n` bytes from the buffered data.
*
* @param {Number} n The number of bytes to consume
* @return {Buffer} The consumed bytes
* @private
*/
consume (n) {
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;
}
/**
* Starts the parsing loop.
*
* @param {Function} cb Callback
* @private
*/
startLoop (cb) {
var err;
this._loop = true;
do {
switch (this._state) {
case GET_INFO:
err = this.getInfo();
break;
case GET_PAYLOAD_LENGTH_16:
err = this.getPayloadLength16();
break;
case GET_PAYLOAD_LENGTH_64:
err = this.getPayloadLength64();
break;
case GET_MASK:
this.getMask();
break;
case GET_DATA:
err = this.getData(cb);
break;
default: // `INFLATING`
this._loop = false;
return;
}
} while (this._loop);
cb(err);
}
/**
* Reads the first two bytes of a frame.
*
* @return {(RangeError|undefined)} A possible error
* @private
*/
getInfo () {
if (this._bufferedBytes < 2) {
this._loop = false;
return;
}
const buf = this.consume(2);
if ((buf[0] & 0x30) !== 0x00) {
this._loop = false;
return error(RangeError, 'RSV2 and RSV3 must be clear', true, 1002);
}
const compressed = (buf[0] & 0x40) === 0x40;
if (compressed && !this._extensions[PerMessageDeflate.extensionName]) {
this._loop = false;
return error(RangeError, 'RSV1 must be clear', true, 1002);
}
this._fin = (buf[0] & 0x80) === 0x80;
this._opcode = buf[0] & 0x0f;
this._payloadLength = buf[1] & 0x7f;
if (this._opcode === 0x00) {
if (compressed) {
this._loop = false;
return error(RangeError, 'RSV1 must be clear', true, 1002);
}
if (!this._fragmented) {
this._loop = false;
return error(RangeError, 'invalid opcode 0', true, 1002);
}
this._opcode = this._fragmented;
} else if (this._opcode === 0x01 || this._opcode === 0x02) {
if (this._fragmented) {
this._loop = false;
return error(RangeError, `invalid opcode ${this._opcode}`, true, 1002);
}
this._compressed = compressed;
} else if (this._opcode > 0x07 && this._opcode < 0x0b) {
if (!this._fin) {
this._loop = false;
return error(RangeError, 'FIN must be set', true, 1002);
}
if (compressed) {
this._loop = false;
return error(RangeError, 'RSV1 must be clear', true, 1002);
}
if (this._payloadLength > 0x7d) {
this._loop = false;
return error(
RangeError,
`invalid payload length ${this._payloadLength}`,
true,
1002
);
}
} else {
this._loop = false;
return error(RangeError, `invalid opcode ${this._opcode}`, true, 1002);
}
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 return this.haveLength();
}
/**
* Gets extended payload length (7+16).
*
* @return {(RangeError|undefined)} A possible error
* @private
*/
getPayloadLength16 () {
if (this._bufferedBytes < 2) {
this._loop = false;
return;
}
this._payloadLength = this.consume(2).readUInt16BE(0);
return this.haveLength();
}
/**
* Gets extended payload length (7+64).
*
* @return {(RangeError|undefined)} A possible error
* @private
*/
getPayloadLength64 () {
if (this._bufferedBytes < 8) {
this._loop = false;
return;
}
const buf = this.consume(8);
const num = buf.readUInt32BE(0);
//
// 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._loop = false;
return error(
RangeError,
'Unsupported WebSocket frame: payload length > 2^53 - 1',
false,
1009
);
}
this._payloadLength = num * Math.pow(2, 32) + buf.readUInt32BE(4);
return this.haveLength();
}
/**
* Payload length has been read.
*
* @return {(RangeError|undefined)} A possible error
* @private
*/
haveLength () {
if (this._payloadLength && this._opcode < 0x08) {
this._totalPayloadLength += this._payloadLength;
if (this._totalPayloadLength > this._maxPayload && this._maxPayload > 0) {
this._loop = false;
return error(RangeError, 'Max payload size exceeded', false, 1009);
}
}
if (this._masked) this._state = GET_MASK;
else this._state = GET_DATA;
}
/**
* Reads mask bytes.
*
* @private
*/
getMask () {
if (this._bufferedBytes < 4) {
this._loop = false;
return;
}
this._mask = this.consume(4);
this._state = GET_DATA;
}
/**
* Reads data bytes.
*
* @param {Function} cb Callback
* @return {(Error|RangeError|undefined)} A possible error
* @private
*/
getData (cb) {
var data = constants.EMPTY_BUFFER;
if (this._payloadLength) {
if (this._bufferedBytes < this._payloadLength) {
this._loop = false;
return;
}
data = this.consume(this._payloadLength);
if (this._masked) bufferUtil.unmask(data, this._mask);
}
if (this._opcode > 0x07) return this.controlMessage(data);
if (this._compressed) {
this._state = INFLATING;
this.decompress(data, cb);
return;
}
if (data.length) {
//
// This message is not compressed so its lenght is the sum of the payload
// length of all fragments.
//
this._messageLength = this._totalPayloadLength;
this._fragments.push(data);
}
return this.dataMessage();
}
/**
* Decompresses data.
*
* @param {Buffer} data Compressed data
* @param {Function} cb Callback
* @private
*/
decompress (data, cb) {
const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
perMessageDeflate.decompress(data, this._fin, (err, buf) => {
if (err) return cb(err);
if (buf.length) {
this._messageLength += buf.length;
if (this._messageLength > this._maxPayload && this._maxPayload > 0) {
return cb(error(RangeError, 'Max payload size exceeded', false, 1009));
}
this._fragments.push(buf);
}
const er = this.dataMessage();
if (er) return cb(er);
this.startLoop(cb);
});
}
/**
* Handles a data message.
*
* @return {(Error|undefined)} A possible error
* @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.emit('message', data);
} else {
const buf = toBuffer(fragments, messageLength);
if (!validation.isValidUTF8(buf)) {
this._loop = false;
return error(Error, 'invalid UTF-8 sequence', true, 1007);
}
this.emit('message', buf.toString());
}
}
this._state = GET_INFO;
}
/**
* Handles a control message.
*
* @param {Buffer} data Data to handle
* @return {(Error|RangeError|undefined)} A possible error
* @private
*/
controlMessage (data) {
if (this._opcode === 0x08) {
this._loop = false;
if (data.length === 0) {
this.emit('conclude', 1005, '');
this.end();
} else if (data.length === 1) {
return error(RangeError, 'invalid payload length 1', true, 1002);
} else {
const code = data.readUInt16BE(0);
if (!validation.isValidStatusCode(code)) {
return error(RangeError, `invalid status code ${code}`, true, 1002);
}
const buf = data.slice(2);
if (!validation.isValidUTF8(buf)) {
return error(Error, 'invalid UTF-8 sequence', true, 1007);
}
this.emit('conclude', code, buf.toString());
this.end();
}
return;
}
if (this._opcode === 0x09) this.emit('ping', data);
else this.emit('pong', data);
this._state = GET_INFO;
}
}
module.exports = Receiver;
/**
* Builds an error object.
*
* @param {(Error|RangeError)} ErrorCtor The error constructor
* @param {String} message The error message
* @param {Boolean} prefix Specifies whether or not to add a default prefix to
* `message`
* @param {Number} statusCode The status code
* @return {(Error|RangeError)} The error
* @private
*/
function error (ErrorCtor, message, prefix, statusCode) {
const err = new ErrorCtor(
prefix ? `Invalid WebSocket frame: ${message}` : message
);
Error.captureStackTrace(err, error);
err[constants.kStatusCode] = statusCode;
return err;
}
/**
* 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);
}