source: trip-planner-front/node_modules/ws/lib/permessage-deflate.js@ 59329aa

Last change on this file since 59329aa was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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1'use strict';
2
3const zlib = require('zlib');
4
5const bufferUtil = require('./buffer-util');
6const Limiter = require('./limiter');
7const { kStatusCode, NOOP } = require('./constants');
8
9const TRAILER = Buffer.from([0x00, 0x00, 0xff, 0xff]);
10const kPerMessageDeflate = Symbol('permessage-deflate');
11const kTotalLength = Symbol('total-length');
12const kCallback = Symbol('callback');
13const kBuffers = Symbol('buffers');
14const kError = Symbol('error');
15
16//
17// We limit zlib concurrency, which prevents severe memory fragmentation
18// as documented in https://github.com/nodejs/node/issues/8871#issuecomment-250915913
19// and https://github.com/websockets/ws/issues/1202
20//
21// Intentionally global; it's the global thread pool that's an issue.
22//
23let zlibLimiter;
24
25/**
26 * permessage-deflate implementation.
27 */
28class PerMessageDeflate {
29 /**
30 * Creates a PerMessageDeflate instance.
31 *
32 * @param {Object} [options] Configuration options
33 * @param {Boolean} [options.serverNoContextTakeover=false] Request/accept
34 * disabling of server context takeover
35 * @param {Boolean} [options.clientNoContextTakeover=false] Advertise/
36 * acknowledge disabling of client context takeover
37 * @param {(Boolean|Number)} [options.serverMaxWindowBits] Request/confirm the
38 * use of a custom server window size
39 * @param {(Boolean|Number)} [options.clientMaxWindowBits] Advertise support
40 * for, or request, a custom client window size
41 * @param {Object} [options.zlibDeflateOptions] Options to pass to zlib on
42 * deflate
43 * @param {Object} [options.zlibInflateOptions] Options to pass to zlib on
44 * inflate
45 * @param {Number} [options.threshold=1024] Size (in bytes) below which
46 * messages should not be compressed
47 * @param {Number} [options.concurrencyLimit=10] The number of concurrent
48 * calls to zlib
49 * @param {Boolean} [isServer=false] Create the instance in either server or
50 * client mode
51 * @param {Number} [maxPayload=0] The maximum allowed message length
52 */
53 constructor(options, isServer, maxPayload) {
54 this._maxPayload = maxPayload | 0;
55 this._options = options || {};
56 this._threshold =
57 this._options.threshold !== undefined ? this._options.threshold : 1024;
58 this._isServer = !!isServer;
59 this._deflate = null;
60 this._inflate = null;
61
62 this.params = null;
63
64 if (!zlibLimiter) {
65 const concurrency =
66 this._options.concurrencyLimit !== undefined
67 ? this._options.concurrencyLimit
68 : 10;
69 zlibLimiter = new Limiter(concurrency);
70 }
71 }
72
73 /**
74 * @type {String}
75 */
76 static get extensionName() {
77 return 'permessage-deflate';
78 }
79
80 /**
81 * Create an extension negotiation offer.
82 *
83 * @return {Object} Extension parameters
84 * @public
85 */
86 offer() {
87 const params = {};
88
89 if (this._options.serverNoContextTakeover) {
90 params.server_no_context_takeover = true;
91 }
92 if (this._options.clientNoContextTakeover) {
93 params.client_no_context_takeover = true;
94 }
95 if (this._options.serverMaxWindowBits) {
96 params.server_max_window_bits = this._options.serverMaxWindowBits;
97 }
98 if (this._options.clientMaxWindowBits) {
99 params.client_max_window_bits = this._options.clientMaxWindowBits;
100 } else if (this._options.clientMaxWindowBits == null) {
101 params.client_max_window_bits = true;
102 }
103
104 return params;
105 }
106
107 /**
108 * Accept an extension negotiation offer/response.
109 *
110 * @param {Array} configurations The extension negotiation offers/reponse
111 * @return {Object} Accepted configuration
112 * @public
113 */
114 accept(configurations) {
115 configurations = this.normalizeParams(configurations);
116
117 this.params = this._isServer
118 ? this.acceptAsServer(configurations)
119 : this.acceptAsClient(configurations);
120
121 return this.params;
122 }
123
124 /**
125 * Releases all resources used by the extension.
126 *
127 * @public
128 */
129 cleanup() {
130 if (this._inflate) {
131 this._inflate.close();
132 this._inflate = null;
133 }
134
135 if (this._deflate) {
136 const callback = this._deflate[kCallback];
137
138 this._deflate.close();
139 this._deflate = null;
140
141 if (callback) {
142 callback(
143 new Error(
144 'The deflate stream was closed while data was being processed'
145 )
146 );
147 }
148 }
149 }
150
151 /**
152 * Accept an extension negotiation offer.
153 *
154 * @param {Array} offers The extension negotiation offers
155 * @return {Object} Accepted configuration
156 * @private
157 */
158 acceptAsServer(offers) {
159 const opts = this._options;
160 const accepted = offers.find((params) => {
161 if (
162 (opts.serverNoContextTakeover === false &&
163 params.server_no_context_takeover) ||
164 (params.server_max_window_bits &&
165 (opts.serverMaxWindowBits === false ||
166 (typeof opts.serverMaxWindowBits === 'number' &&
167 opts.serverMaxWindowBits > params.server_max_window_bits))) ||
168 (typeof opts.clientMaxWindowBits === 'number' &&
169 !params.client_max_window_bits)
170 ) {
171 return false;
172 }
173
174 return true;
175 });
176
177 if (!accepted) {
178 throw new Error('None of the extension offers can be accepted');
179 }
180
181 if (opts.serverNoContextTakeover) {
182 accepted.server_no_context_takeover = true;
183 }
184 if (opts.clientNoContextTakeover) {
185 accepted.client_no_context_takeover = true;
186 }
187 if (typeof opts.serverMaxWindowBits === 'number') {
188 accepted.server_max_window_bits = opts.serverMaxWindowBits;
189 }
190 if (typeof opts.clientMaxWindowBits === 'number') {
191 accepted.client_max_window_bits = opts.clientMaxWindowBits;
192 } else if (
193 accepted.client_max_window_bits === true ||
194 opts.clientMaxWindowBits === false
195 ) {
196 delete accepted.client_max_window_bits;
197 }
198
199 return accepted;
200 }
201
202 /**
203 * Accept the extension negotiation response.
204 *
205 * @param {Array} response The extension negotiation response
206 * @return {Object} Accepted configuration
207 * @private
208 */
209 acceptAsClient(response) {
210 const params = response[0];
211
212 if (
213 this._options.clientNoContextTakeover === false &&
214 params.client_no_context_takeover
215 ) {
216 throw new Error('Unexpected parameter "client_no_context_takeover"');
217 }
218
219 if (!params.client_max_window_bits) {
220 if (typeof this._options.clientMaxWindowBits === 'number') {
221 params.client_max_window_bits = this._options.clientMaxWindowBits;
222 }
223 } else if (
224 this._options.clientMaxWindowBits === false ||
225 (typeof this._options.clientMaxWindowBits === 'number' &&
226 params.client_max_window_bits > this._options.clientMaxWindowBits)
227 ) {
228 throw new Error(
229 'Unexpected or invalid parameter "client_max_window_bits"'
230 );
231 }
232
233 return params;
234 }
235
236 /**
237 * Normalize parameters.
238 *
239 * @param {Array} configurations The extension negotiation offers/reponse
240 * @return {Array} The offers/response with normalized parameters
241 * @private
242 */
243 normalizeParams(configurations) {
244 configurations.forEach((params) => {
245 Object.keys(params).forEach((key) => {
246 let value = params[key];
247
248 if (value.length > 1) {
249 throw new Error(`Parameter "${key}" must have only a single value`);
250 }
251
252 value = value[0];
253
254 if (key === 'client_max_window_bits') {
255 if (value !== true) {
256 const num = +value;
257 if (!Number.isInteger(num) || num < 8 || num > 15) {
258 throw new TypeError(
259 `Invalid value for parameter "${key}": ${value}`
260 );
261 }
262 value = num;
263 } else if (!this._isServer) {
264 throw new TypeError(
265 `Invalid value for parameter "${key}": ${value}`
266 );
267 }
268 } else if (key === 'server_max_window_bits') {
269 const num = +value;
270 if (!Number.isInteger(num) || num < 8 || num > 15) {
271 throw new TypeError(
272 `Invalid value for parameter "${key}": ${value}`
273 );
274 }
275 value = num;
276 } else if (
277 key === 'client_no_context_takeover' ||
278 key === 'server_no_context_takeover'
279 ) {
280 if (value !== true) {
281 throw new TypeError(
282 `Invalid value for parameter "${key}": ${value}`
283 );
284 }
285 } else {
286 throw new Error(`Unknown parameter "${key}"`);
287 }
288
289 params[key] = value;
290 });
291 });
292
293 return configurations;
294 }
295
296 /**
297 * Decompress data. Concurrency limited.
298 *
299 * @param {Buffer} data Compressed data
300 * @param {Boolean} fin Specifies whether or not this is the last fragment
301 * @param {Function} callback Callback
302 * @public
303 */
304 decompress(data, fin, callback) {
305 zlibLimiter.add((done) => {
306 this._decompress(data, fin, (err, result) => {
307 done();
308 callback(err, result);
309 });
310 });
311 }
312
313 /**
314 * Compress data. Concurrency limited.
315 *
316 * @param {Buffer} data Data to compress
317 * @param {Boolean} fin Specifies whether or not this is the last fragment
318 * @param {Function} callback Callback
319 * @public
320 */
321 compress(data, fin, callback) {
322 zlibLimiter.add((done) => {
323 this._compress(data, fin, (err, result) => {
324 done();
325 callback(err, result);
326 });
327 });
328 }
329
330 /**
331 * Decompress data.
332 *
333 * @param {Buffer} data Compressed data
334 * @param {Boolean} fin Specifies whether or not this is the last fragment
335 * @param {Function} callback Callback
336 * @private
337 */
338 _decompress(data, fin, callback) {
339 const endpoint = this._isServer ? 'client' : 'server';
340
341 if (!this._inflate) {
342 const key = `${endpoint}_max_window_bits`;
343 const windowBits =
344 typeof this.params[key] !== 'number'
345 ? zlib.Z_DEFAULT_WINDOWBITS
346 : this.params[key];
347
348 this._inflate = zlib.createInflateRaw({
349 ...this._options.zlibInflateOptions,
350 windowBits
351 });
352 this._inflate[kPerMessageDeflate] = this;
353 this._inflate[kTotalLength] = 0;
354 this._inflate[kBuffers] = [];
355 this._inflate.on('error', inflateOnError);
356 this._inflate.on('data', inflateOnData);
357 }
358
359 this._inflate[kCallback] = callback;
360
361 this._inflate.write(data);
362 if (fin) this._inflate.write(TRAILER);
363
364 this._inflate.flush(() => {
365 const err = this._inflate[kError];
366
367 if (err) {
368 this._inflate.close();
369 this._inflate = null;
370 callback(err);
371 return;
372 }
373
374 const data = bufferUtil.concat(
375 this._inflate[kBuffers],
376 this._inflate[kTotalLength]
377 );
378
379 if (this._inflate._readableState.endEmitted) {
380 this._inflate.close();
381 this._inflate = null;
382 } else {
383 this._inflate[kTotalLength] = 0;
384 this._inflate[kBuffers] = [];
385
386 if (fin && this.params[`${endpoint}_no_context_takeover`]) {
387 this._inflate.reset();
388 }
389 }
390
391 callback(null, data);
392 });
393 }
394
395 /**
396 * Compress data.
397 *
398 * @param {Buffer} data Data to compress
399 * @param {Boolean} fin Specifies whether or not this is the last fragment
400 * @param {Function} callback Callback
401 * @private
402 */
403 _compress(data, fin, callback) {
404 const endpoint = this._isServer ? 'server' : 'client';
405
406 if (!this._deflate) {
407 const key = `${endpoint}_max_window_bits`;
408 const windowBits =
409 typeof this.params[key] !== 'number'
410 ? zlib.Z_DEFAULT_WINDOWBITS
411 : this.params[key];
412
413 this._deflate = zlib.createDeflateRaw({
414 ...this._options.zlibDeflateOptions,
415 windowBits
416 });
417
418 this._deflate[kTotalLength] = 0;
419 this._deflate[kBuffers] = [];
420
421 //
422 // An `'error'` event is emitted, only on Node.js < 10.0.0, if the
423 // `zlib.DeflateRaw` instance is closed while data is being processed.
424 // This can happen if `PerMessageDeflate#cleanup()` is called at the wrong
425 // time due to an abnormal WebSocket closure.
426 //
427 this._deflate.on('error', NOOP);
428 this._deflate.on('data', deflateOnData);
429 }
430
431 this._deflate[kCallback] = callback;
432
433 this._deflate.write(data);
434 this._deflate.flush(zlib.Z_SYNC_FLUSH, () => {
435 if (!this._deflate) {
436 //
437 // The deflate stream was closed while data was being processed.
438 //
439 return;
440 }
441
442 let data = bufferUtil.concat(
443 this._deflate[kBuffers],
444 this._deflate[kTotalLength]
445 );
446
447 if (fin) data = data.slice(0, data.length - 4);
448
449 //
450 // Ensure that the callback will not be called again in
451 // `PerMessageDeflate#cleanup()`.
452 //
453 this._deflate[kCallback] = null;
454
455 this._deflate[kTotalLength] = 0;
456 this._deflate[kBuffers] = [];
457
458 if (fin && this.params[`${endpoint}_no_context_takeover`]) {
459 this._deflate.reset();
460 }
461
462 callback(null, data);
463 });
464 }
465}
466
467module.exports = PerMessageDeflate;
468
469/**
470 * The listener of the `zlib.DeflateRaw` stream `'data'` event.
471 *
472 * @param {Buffer} chunk A chunk of data
473 * @private
474 */
475function deflateOnData(chunk) {
476 this[kBuffers].push(chunk);
477 this[kTotalLength] += chunk.length;
478}
479
480/**
481 * The listener of the `zlib.InflateRaw` stream `'data'` event.
482 *
483 * @param {Buffer} chunk A chunk of data
484 * @private
485 */
486function inflateOnData(chunk) {
487 this[kTotalLength] += chunk.length;
488
489 if (
490 this[kPerMessageDeflate]._maxPayload < 1 ||
491 this[kTotalLength] <= this[kPerMessageDeflate]._maxPayload
492 ) {
493 this[kBuffers].push(chunk);
494 return;
495 }
496
497 this[kError] = new RangeError('Max payload size exceeded');
498 this[kError][kStatusCode] = 1009;
499 this.removeListener('data', inflateOnData);
500 this.reset();
501}
502
503/**
504 * The listener of the `zlib.InflateRaw` stream `'error'` event.
505 *
506 * @param {Error} err The emitted error
507 * @private
508 */
509function inflateOnError(err) {
510 //
511 // There is no need to call `Zlib#close()` as the handle is automatically
512 // closed when an error is emitted.
513 //
514 this[kPerMessageDeflate]._inflate = null;
515 err[kStatusCode] = 1007;
516 this[kCallback](err);
517}
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