--- /dev/null
+'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);
+}
projects / VSoRC / .git / blobdiff