508 lines
14 KiB
JavaScript
508 lines
14 KiB
JavaScript
'use strict';
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const safeBuffer = require('safe-buffer');
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const Limiter = require('async-limiter');
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const zlib = require('zlib');
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const bufferUtil = require('./BufferUtil');
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const Buffer = safeBuffer.Buffer;
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const TRAILER = Buffer.from([0x00, 0x00, 0xff, 0xff]);
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const EMPTY_BLOCK = Buffer.from([0x00]);
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const kWriteInProgress = Symbol('write-in-progress');
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const kPendingClose = Symbol('pending-close');
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const kTotalLength = Symbol('total-length');
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const kCallback = Symbol('callback');
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const kBuffers = Symbol('buffers');
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const kError = Symbol('error');
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const kOwner = Symbol('owner');
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//
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// We limit zlib concurrency, which prevents severe memory fragmentation
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// as documented in https://github.com/nodejs/node/issues/8871#issuecomment-250915913
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// and https://github.com/websockets/ws/issues/1202
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//
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// Intentionally global; it's the global thread pool that's an issue.
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//
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let zlibLimiter;
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/**
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* permessage-deflate implementation.
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*/
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class PerMessageDeflate {
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/**
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* Creates a PerMessageDeflate instance.
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*
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* @param {Object} options Configuration options
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* @param {Boolean} options.serverNoContextTakeover Request/accept disabling
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* of server context takeover
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* @param {Boolean} options.clientNoContextTakeover Advertise/acknowledge
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* disabling of client context takeover
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* @param {(Boolean|Number)} options.serverMaxWindowBits Request/confirm the
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* use of a custom server window size
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* @param {(Boolean|Number)} options.clientMaxWindowBits Advertise support
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* for, or request, a custom client window size
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* @param {Number} options.level The value of zlib's `level` param
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* @param {Number} options.memLevel The value of zlib's `memLevel` param
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* @param {Number} options.threshold Size (in bytes) below which messages
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* should not be compressed
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* @param {Number} options.concurrencyLimit The number of concurrent calls to
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* zlib
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* @param {Boolean} isServer Create the instance in either server or client
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* mode
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* @param {Number} maxPayload The maximum allowed message length
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*/
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constructor (options, isServer, maxPayload) {
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this._maxPayload = maxPayload | 0;
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this._options = options || {};
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this._threshold = this._options.threshold !== undefined
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? this._options.threshold
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: 1024;
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this._isServer = !!isServer;
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this._deflate = null;
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this._inflate = null;
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this.params = null;
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if (!zlibLimiter) {
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const concurrency = this._options.concurrencyLimit !== undefined
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? this._options.concurrencyLimit
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: 10;
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zlibLimiter = new Limiter({ concurrency });
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}
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}
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/**
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* @type {String}
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*/
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static get extensionName () {
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return 'permessage-deflate';
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}
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/**
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* Create extension parameters offer.
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*
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* @return {Object} Extension parameters
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* @public
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*/
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offer () {
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const params = {};
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if (this._options.serverNoContextTakeover) {
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params.server_no_context_takeover = true;
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}
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if (this._options.clientNoContextTakeover) {
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params.client_no_context_takeover = true;
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}
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if (this._options.serverMaxWindowBits) {
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params.server_max_window_bits = this._options.serverMaxWindowBits;
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}
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if (this._options.clientMaxWindowBits) {
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params.client_max_window_bits = this._options.clientMaxWindowBits;
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} else if (this._options.clientMaxWindowBits == null) {
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params.client_max_window_bits = true;
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}
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return params;
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}
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/**
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* Accept extension offer.
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*
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* @param {Array} paramsList Extension parameters
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* @return {Object} Accepted configuration
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* @public
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*/
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accept (paramsList) {
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paramsList = this.normalizeParams(paramsList);
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var params;
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if (this._isServer) {
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params = this.acceptAsServer(paramsList);
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} else {
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params = this.acceptAsClient(paramsList);
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}
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this.params = params;
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return params;
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}
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/**
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* Releases all resources used by the extension.
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*
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* @public
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*/
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cleanup () {
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if (this._inflate) {
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if (this._inflate[kWriteInProgress]) {
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this._inflate[kPendingClose] = true;
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} else {
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this._inflate.close();
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this._inflate = null;
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}
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}
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if (this._deflate) {
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if (this._deflate[kWriteInProgress]) {
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this._deflate[kPendingClose] = true;
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} else {
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this._deflate.close();
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this._deflate = null;
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}
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}
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}
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/**
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* Accept extension offer from client.
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*
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* @param {Array} paramsList Extension parameters
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* @return {Object} Accepted configuration
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* @private
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*/
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acceptAsServer (paramsList) {
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const accepted = {};
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const result = paramsList.some((params) => {
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if (
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(this._options.serverNoContextTakeover === false &&
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params.server_no_context_takeover) ||
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(this._options.serverMaxWindowBits === false &&
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params.server_max_window_bits) ||
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(typeof this._options.serverMaxWindowBits === 'number' &&
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typeof params.server_max_window_bits === 'number' &&
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this._options.serverMaxWindowBits > params.server_max_window_bits) ||
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(typeof this._options.clientMaxWindowBits === 'number' &&
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!params.client_max_window_bits)
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) {
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return;
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}
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if (
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this._options.serverNoContextTakeover ||
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params.server_no_context_takeover
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) {
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accepted.server_no_context_takeover = true;
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}
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if (
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this._options.clientNoContextTakeover ||
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(this._options.clientNoContextTakeover !== false &&
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params.client_no_context_takeover)
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) {
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accepted.client_no_context_takeover = true;
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}
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if (typeof this._options.serverMaxWindowBits === 'number') {
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accepted.server_max_window_bits = this._options.serverMaxWindowBits;
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} else if (typeof params.server_max_window_bits === 'number') {
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accepted.server_max_window_bits = params.server_max_window_bits;
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}
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if (typeof this._options.clientMaxWindowBits === 'number') {
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accepted.client_max_window_bits = this._options.clientMaxWindowBits;
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} else if (
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this._options.clientMaxWindowBits !== false &&
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typeof params.client_max_window_bits === 'number'
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) {
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accepted.client_max_window_bits = params.client_max_window_bits;
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}
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return true;
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});
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if (!result) throw new Error("Doesn't support the offered configuration");
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return accepted;
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}
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/**
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* Accept extension response from server.
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*
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* @param {Array} paramsList Extension parameters
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* @return {Object} Accepted configuration
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* @private
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*/
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acceptAsClient (paramsList) {
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const params = paramsList[0];
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if (
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this._options.clientNoContextTakeover === false &&
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params.client_no_context_takeover
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) {
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throw new Error('Invalid value for "client_no_context_takeover"');
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}
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if (
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(typeof this._options.clientMaxWindowBits === 'number' &&
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(!params.client_max_window_bits ||
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params.client_max_window_bits > this._options.clientMaxWindowBits)) ||
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(this._options.clientMaxWindowBits === false &&
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params.client_max_window_bits)
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) {
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throw new Error('Invalid value for "client_max_window_bits"');
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}
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return params;
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}
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/**
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* Normalize extensions parameters.
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*
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* @param {Array} paramsList Extension parameters
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* @return {Array} Normalized extensions parameters
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* @private
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*/
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normalizeParams (paramsList) {
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return paramsList.map((params) => {
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Object.keys(params).forEach((key) => {
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var value = params[key];
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if (value.length > 1) {
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throw new Error(`Multiple extension parameters for ${key}`);
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}
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value = value[0];
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switch (key) {
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case 'server_no_context_takeover':
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case 'client_no_context_takeover':
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if (value !== true) {
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throw new Error(`invalid extension parameter value for ${key} (${value})`);
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}
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params[key] = true;
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break;
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case 'server_max_window_bits':
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case 'client_max_window_bits':
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if (typeof value === 'string') {
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value = parseInt(value, 10);
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if (
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Number.isNaN(value) ||
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value < zlib.Z_MIN_WINDOWBITS ||
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value > zlib.Z_MAX_WINDOWBITS
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) {
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throw new Error(`invalid extension parameter value for ${key} (${value})`);
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}
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}
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if (!this._isServer && value === true) {
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throw new Error(`Missing extension parameter value for ${key}`);
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}
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params[key] = value;
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break;
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default:
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throw new Error(`Not defined extension parameter (${key})`);
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}
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});
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return params;
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});
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}
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/**
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* Decompress data. Concurrency limited by async-limiter.
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*
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* @param {Buffer} data Compressed data
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* @param {Boolean} fin Specifies whether or not this is the last fragment
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* @param {Function} callback Callback
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* @public
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*/
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decompress (data, fin, callback) {
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zlibLimiter.push((done) => {
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this._decompress(data, fin, (err, result) => {
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done();
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callback(err, result);
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});
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});
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}
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/**
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* Compress data. Concurrency limited by async-limiter.
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*
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* @param {Buffer} data Data to compress
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* @param {Boolean} fin Specifies whether or not this is the last fragment
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* @param {Function} callback Callback
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* @public
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*/
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compress (data, fin, callback) {
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zlibLimiter.push((done) => {
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this._compress(data, fin, (err, result) => {
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done();
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callback(err, result);
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});
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});
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}
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/**
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* Decompress data.
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*
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* @param {Buffer} data Compressed data
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* @param {Boolean} fin Specifies whether or not this is the last fragment
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* @param {Function} callback Callback
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* @private
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*/
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_decompress (data, fin, callback) {
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const endpoint = this._isServer ? 'client' : 'server';
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if (!this._inflate) {
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const key = `${endpoint}_max_window_bits`;
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const windowBits = typeof this.params[key] !== 'number'
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? zlib.Z_DEFAULT_WINDOWBITS
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: this.params[key];
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this._inflate = zlib.createInflateRaw({ windowBits });
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this._inflate[kTotalLength] = 0;
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this._inflate[kBuffers] = [];
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this._inflate[kOwner] = this;
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this._inflate.on('error', inflateOnError);
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this._inflate.on('data', inflateOnData);
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}
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this._inflate[kCallback] = callback;
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this._inflate[kWriteInProgress] = true;
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this._inflate.write(data);
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if (fin) this._inflate.write(TRAILER);
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this._inflate.flush(() => {
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const err = this._inflate[kError];
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if (err) {
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this._inflate.close();
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this._inflate = null;
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callback(err);
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return;
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}
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const data = bufferUtil.concat(
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this._inflate[kBuffers],
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this._inflate[kTotalLength]
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);
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if (
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(fin && this.params[`${endpoint}_no_context_takeover`]) ||
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this._inflate[kPendingClose]
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) {
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this._inflate.close();
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this._inflate = null;
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} else {
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this._inflate[kWriteInProgress] = false;
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this._inflate[kTotalLength] = 0;
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this._inflate[kBuffers] = [];
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}
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callback(null, data);
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});
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}
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/**
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* Compress data.
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*
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* @param {Buffer} data Data to compress
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* @param {Boolean} fin Specifies whether or not this is the last fragment
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* @param {Function} callback Callback
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* @private
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*/
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_compress (data, fin, callback) {
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if (!data || data.length === 0) {
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process.nextTick(callback, null, EMPTY_BLOCK);
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return;
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}
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const endpoint = this._isServer ? 'server' : 'client';
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if (!this._deflate) {
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const key = `${endpoint}_max_window_bits`;
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const windowBits = typeof this.params[key] !== 'number'
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? zlib.Z_DEFAULT_WINDOWBITS
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: this.params[key];
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this._deflate = zlib.createDeflateRaw({
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memLevel: this._options.memLevel,
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level: this._options.level,
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flush: zlib.Z_SYNC_FLUSH,
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windowBits
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});
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this._deflate[kTotalLength] = 0;
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this._deflate[kBuffers] = [];
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//
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// `zlib.DeflateRaw` emits an `'error'` event only when an attempt to use
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// it is made after it has already been closed. This cannot happen here,
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// so we only add a listener for the `'data'` event.
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//
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this._deflate.on('data', deflateOnData);
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}
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this._deflate[kWriteInProgress] = true;
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this._deflate.write(data);
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this._deflate.flush(zlib.Z_SYNC_FLUSH, () => {
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var data = bufferUtil.concat(
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this._deflate[kBuffers],
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this._deflate[kTotalLength]
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);
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if (fin) data = data.slice(0, data.length - 4);
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if (
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(fin && this.params[`${endpoint}_no_context_takeover`]) ||
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this._deflate[kPendingClose]
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) {
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this._deflate.close();
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this._deflate = null;
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} else {
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this._deflate[kWriteInProgress] = false;
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this._deflate[kTotalLength] = 0;
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this._deflate[kBuffers] = [];
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}
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callback(null, data);
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});
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}
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}
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module.exports = PerMessageDeflate;
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/**
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* The listener of the `zlib.DeflateRaw` stream `'data'` event.
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*
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* @param {Buffer} chunk A chunk of data
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* @private
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*/
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function deflateOnData (chunk) {
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this[kBuffers].push(chunk);
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this[kTotalLength] += chunk.length;
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}
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/**
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* The listener of the `zlib.InflateRaw` stream `'data'` event.
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*
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* @param {Buffer} chunk A chunk of data
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* @private
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*/
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function inflateOnData (chunk) {
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this[kTotalLength] += chunk.length;
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if (
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this[kOwner]._maxPayload < 1 ||
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this[kTotalLength] <= this[kOwner]._maxPayload
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) {
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this[kBuffers].push(chunk);
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return;
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}
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this[kError] = new Error('max payload size exceeded');
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this[kError].closeCode = 1009;
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this.removeListener('data', inflateOnData);
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this.reset();
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}
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/**
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* The listener of the `zlib.InflateRaw` stream `'error'` event.
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*
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* @param {Error} err The emitted error
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* @private
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*/
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function inflateOnError (err) {
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//
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// There is no need to call `Zlib#close()` as the handle is automatically
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// closed when an error is emitted.
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//
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this[kOwner]._inflate = null;
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this[kCallback](err);
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}
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