diff options
Diffstat (limited to 'node_modules/ws/lib/receiver.js')
| -rw-r--r-- | node_modules/ws/lib/receiver.js | 706 |
1 files changed, 706 insertions, 0 deletions
diff --git a/node_modules/ws/lib/receiver.js b/node_modules/ws/lib/receiver.js new file mode 100644 index 0000000..54d9b4f --- /dev/null +++ b/node_modules/ws/lib/receiver.js @@ -0,0 +1,706 @@ +'use strict'; + +const { Writable } = require('stream'); + +const PerMessageDeflate = require('./permessage-deflate'); +const { + BINARY_TYPES, + EMPTY_BUFFER, + kStatusCode, + kWebSocket +} = require('./constants'); +const { concat, toArrayBuffer, unmask } = require('./buffer-util'); +const { isValidStatusCode, isValidUTF8 } = require('./validation'); + +const FastBuffer = Buffer[Symbol.species]; + +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; +const DEFER_EVENT = 6; + +/** + * HyBi Receiver implementation. + * + * @extends Writable + */ +class Receiver extends Writable { + /** + * Creates a Receiver instance. + * + * @param {Object} [options] Options object + * @param {Boolean} [options.allowSynchronousEvents=true] Specifies whether + * any of the `'message'`, `'ping'`, and `'pong'` events can be emitted + * multiple times in the same tick + * @param {String} [options.binaryType=nodebuffer] The type for binary data + * @param {Object} [options.extensions] An object containing the negotiated + * extensions + * @param {Boolean} [options.isServer=false] Specifies whether to operate in + * client or server mode + * @param {Number} [options.maxPayload=0] The maximum allowed message length + * @param {Boolean} [options.skipUTF8Validation=false] Specifies whether or + * not to skip UTF-8 validation for text and close messages + */ + constructor(options = {}) { + super(); + + this._allowSynchronousEvents = + options.allowSynchronousEvents !== undefined + ? options.allowSynchronousEvents + : true; + this._binaryType = options.binaryType || BINARY_TYPES[0]; + this._extensions = options.extensions || {}; + this._isServer = !!options.isServer; + this._maxPayload = options.maxPayload | 0; + this._skipUTF8Validation = !!options.skipUTF8Validation; + this[kWebSocket] = undefined; + + 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._errored = false; + this._loop = false; + this._state = GET_INFO; + } + + /** + * 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 + * @private + */ + _write(chunk, encoding, cb) { + if (this._opcode === 0x08 && this._state == GET_INFO) 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] = new FastBuffer( + buf.buffer, + buf.byteOffset + n, + buf.length - n + ); + + return new FastBuffer(buf.buffer, buf.byteOffset, n); + } + + const dst = Buffer.allocUnsafe(n); + + do { + const buf = this._buffers[0]; + const offset = dst.length - n; + + if (n >= buf.length) { + dst.set(this._buffers.shift(), offset); + } else { + dst.set(new Uint8Array(buf.buffer, buf.byteOffset, n), offset); + this._buffers[0] = new FastBuffer( + buf.buffer, + buf.byteOffset + n, + buf.length - n + ); + } + + n -= buf.length; + } while (n > 0); + + return dst; + } + + /** + * Starts the parsing loop. + * + * @param {Function} cb Callback + * @private + */ + startLoop(cb) { + this._loop = true; + + do { + switch (this._state) { + case GET_INFO: + this.getInfo(cb); + break; + case GET_PAYLOAD_LENGTH_16: + this.getPayloadLength16(cb); + break; + case GET_PAYLOAD_LENGTH_64: + this.getPayloadLength64(cb); + break; + case GET_MASK: + this.getMask(); + break; + case GET_DATA: + this.getData(cb); + break; + case INFLATING: + case DEFER_EVENT: + this._loop = false; + return; + } + } while (this._loop); + + if (!this._errored) cb(); + } + + /** + * Reads the first two bytes of a frame. + * + * @param {Function} cb Callback + * @private + */ + getInfo(cb) { + if (this._bufferedBytes < 2) { + this._loop = false; + return; + } + + const buf = this.consume(2); + + if ((buf[0] & 0x30) !== 0x00) { + const error = this.createError( + RangeError, + 'RSV2 and RSV3 must be clear', + true, + 1002, + 'WS_ERR_UNEXPECTED_RSV_2_3' + ); + + cb(error); + return; + } + + const compressed = (buf[0] & 0x40) === 0x40; + + if (compressed && !this._extensions[PerMessageDeflate.extensionName]) { + const error = this.createError( + RangeError, + 'RSV1 must be clear', + true, + 1002, + 'WS_ERR_UNEXPECTED_RSV_1' + ); + + cb(error); + return; + } + + this._fin = (buf[0] & 0x80) === 0x80; + this._opcode = buf[0] & 0x0f; + this._payloadLength = buf[1] & 0x7f; + + if (this._opcode === 0x00) { + if (compressed) { + const error = this.createError( + RangeError, + 'RSV1 must be clear', + true, + 1002, + 'WS_ERR_UNEXPECTED_RSV_1' + ); + + cb(error); + return; + } + + if (!this._fragmented) { + const error = this.createError( + RangeError, + 'invalid opcode 0', + true, + 1002, + 'WS_ERR_INVALID_OPCODE' + ); + + cb(error); + return; + } + + this._opcode = this._fragmented; + } else if (this._opcode === 0x01 || this._opcode === 0x02) { + if (this._fragmented) { + const error = this.createError( + RangeError, + `invalid opcode ${this._opcode}`, + true, + 1002, + 'WS_ERR_INVALID_OPCODE' + ); + + cb(error); + return; + } + + this._compressed = compressed; + } else if (this._opcode > 0x07 && this._opcode < 0x0b) { + if (!this._fin) { + const error = this.createError( + RangeError, + 'FIN must be set', + true, + 1002, + 'WS_ERR_EXPECTED_FIN' + ); + + cb(error); + return; + } + + if (compressed) { + const error = this.createError( + RangeError, + 'RSV1 must be clear', + true, + 1002, + 'WS_ERR_UNEXPECTED_RSV_1' + ); + + cb(error); + return; + } + + if ( + this._payloadLength > 0x7d || + (this._opcode === 0x08 && this._payloadLength === 1) + ) { + const error = this.createError( + RangeError, + `invalid payload length ${this._payloadLength}`, + true, + 1002, + 'WS_ERR_INVALID_CONTROL_PAYLOAD_LENGTH' + ); + + cb(error); + return; + } + } else { + const error = this.createError( + RangeError, + `invalid opcode ${this._opcode}`, + true, + 1002, + 'WS_ERR_INVALID_OPCODE' + ); + + cb(error); + return; + } + + if (!this._fin && !this._fragmented) this._fragmented = this._opcode; + this._masked = (buf[1] & 0x80) === 0x80; + + if (this._isServer) { + if (!this._masked) { + const error = this.createError( + RangeError, + 'MASK must be set', + true, + 1002, + 'WS_ERR_EXPECTED_MASK' + ); + + cb(error); + return; + } + } else if (this._masked) { + const error = this.createError( + RangeError, + 'MASK must be clear', + true, + 1002, + 'WS_ERR_UNEXPECTED_MASK' + ); + + cb(error); + return; + } + + if (this._payloadLength === 126) this._state = GET_PAYLOAD_LENGTH_16; + else if (this._payloadLength === 127) this._state = GET_PAYLOAD_LENGTH_64; + else this.haveLength(cb); + } + + /** + * Gets extended payload length (7+16). + * + * @param {Function} cb Callback + * @private + */ + getPayloadLength16(cb) { + if (this._bufferedBytes < 2) { + this._loop = false; + return; + } + + this._payloadLength = this.consume(2).readUInt16BE(0); + this.haveLength(cb); + } + + /** + * Gets extended payload length (7+64). + * + * @param {Function} cb Callback + * @private + */ + getPayloadLength64(cb) { + 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) { + const error = this.createError( + RangeError, + 'Unsupported WebSocket frame: payload length > 2^53 - 1', + false, + 1009, + 'WS_ERR_UNSUPPORTED_DATA_PAYLOAD_LENGTH' + ); + + cb(error); + return; + } + + this._payloadLength = num * Math.pow(2, 32) + buf.readUInt32BE(4); + this.haveLength(cb); + } + + /** + * Payload length has been read. + * + * @param {Function} cb Callback + * @private + */ + haveLength(cb) { + if (this._payloadLength && this._opcode < 0x08) { + this._totalPayloadLength += this._payloadLength; + if (this._totalPayloadLength > this._maxPayload && this._maxPayload > 0) { + const error = this.createError( + RangeError, + 'Max payload size exceeded', + false, + 1009, + 'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH' + ); + + cb(error); + return; + } + } + + 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 + * @private + */ + getData(cb) { + let data = EMPTY_BUFFER; + + if (this._payloadLength) { + if (this._bufferedBytes < this._payloadLength) { + this._loop = false; + return; + } + + data = this.consume(this._payloadLength); + + if ( + this._masked && + (this._mask[0] | this._mask[1] | this._mask[2] | this._mask[3]) !== 0 + ) { + unmask(data, this._mask); + } + } + + if (this._opcode > 0x07) { + this.controlMessage(data, cb); + return; + } + + if (this._compressed) { + this._state = INFLATING; + this.decompress(data, cb); + return; + } + + if (data.length) { + // + // This message is not compressed so its length is the sum of the payload + // length of all fragments. + // + this._messageLength = this._totalPayloadLength; + this._fragments.push(data); + } + + this.dataMessage(cb); + } + + /** + * 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) { + const error = this.createError( + RangeError, + 'Max payload size exceeded', + false, + 1009, + 'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH' + ); + + cb(error); + return; + } + + this._fragments.push(buf); + } + + this.dataMessage(cb); + if (this._state === GET_INFO) this.startLoop(cb); + }); + } + + /** + * Handles a data message. + * + * @param {Function} cb Callback + * @private + */ + dataMessage(cb) { + if (!this._fin) { + this._state = GET_INFO; + return; + } + + const messageLength = this._messageLength; + const fragments = this._fragments; + + this._totalPayloadLength = 0; + this._messageLength = 0; + this._fragmented = 0; + this._fragments = []; + + if (this._opcode === 2) { + let data; + + if (this._binaryType === 'nodebuffer') { + data = concat(fragments, messageLength); + } else if (this._binaryType === 'arraybuffer') { + data = toArrayBuffer(concat(fragments, messageLength)); + } else if (this._binaryType === 'blob') { + data = new Blob(fragments); + } else { + data = fragments; + } + + if (this._allowSynchronousEvents) { + this.emit('message', data, true); + this._state = GET_INFO; + } else { + this._state = DEFER_EVENT; + setImmediate(() => { + this.emit('message', data, true); + this._state = GET_INFO; + this.startLoop(cb); + }); + } + } else { + const buf = concat(fragments, messageLength); + + if (!this._skipUTF8Validation && !isValidUTF8(buf)) { + const error = this.createError( + Error, + 'invalid UTF-8 sequence', + true, + 1007, + 'WS_ERR_INVALID_UTF8' + ); + + cb(error); + return; + } + + if (this._state === INFLATING || this._allowSynchronousEvents) { + this.emit('message', buf, false); + this._state = GET_INFO; + } else { + this._state = DEFER_EVENT; + setImmediate(() => { + this.emit('message', buf, false); + this._state = GET_INFO; + this.startLoop(cb); + }); + } + } + } + + /** + * Handles a control message. + * + * @param {Buffer} data Data to handle + * @return {(Error|RangeError|undefined)} A possible error + * @private + */ + controlMessage(data, cb) { + if (this._opcode === 0x08) { + if (data.length === 0) { + this._loop = false; + this.emit('conclude', 1005, EMPTY_BUFFER); + this.end(); + } else { + const code = data.readUInt16BE(0); + + if (!isValidStatusCode(code)) { + const error = this.createError( + RangeError, + `invalid status code ${code}`, + true, + 1002, + 'WS_ERR_INVALID_CLOSE_CODE' + ); + + cb(error); + return; + } + + const buf = new FastBuffer( + data.buffer, + data.byteOffset + 2, + data.length - 2 + ); + + if (!this._skipUTF8Validation && !isValidUTF8(buf)) { + const error = this.createError( + Error, + 'invalid UTF-8 sequence', + true, + 1007, + 'WS_ERR_INVALID_UTF8' + ); + + cb(error); + return; + } + + this._loop = false; + this.emit('conclude', code, buf); + this.end(); + } + + this._state = GET_INFO; + return; + } + + if (this._allowSynchronousEvents) { + this.emit(this._opcode === 0x09 ? 'ping' : 'pong', data); + this._state = GET_INFO; + } else { + this._state = DEFER_EVENT; + setImmediate(() => { + this.emit(this._opcode === 0x09 ? 'ping' : 'pong', data); + this._state = GET_INFO; + this.startLoop(cb); + }); + } + } + + /** + * Builds an error object. + * + * @param {function(new: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 + * @param {String} errorCode The exposed error code + * @return {(Error|RangeError)} The error + * @private + */ + createError(ErrorCtor, message, prefix, statusCode, errorCode) { + this._loop = false; + this._errored = true; + + const err = new ErrorCtor( + prefix ? `Invalid WebSocket frame: ${message}` : message + ); + + Error.captureStackTrace(err, this.createError); + err.code = errorCode; + err[kStatusCode] = statusCode; + return err; + } +} + +module.exports = Receiver; |