bufferutil

Install bufferutil as an optional dependency using npm. This is recommended because bufferutil provides performance optimizations for WebSocket operations, but the application can still function without it if the native build fails.

npm install bufferutil --save-optional

The bufferUtil.mask() function masks a buffer using a provided masking-key according to the WebSocket protocol.

Note: To maximize performance, parameters are not validated. You must ensure all arguments are correct before calling the function.

Arguments:

• source: The buffer to mask.
• mask: A buffer representing the 4-byte masking-key.
• output: The buffer where the masked result will be stored.
• offset: The byte offset at which to start writing in the output buffer.
• length: The number of bytes to mask.

'use strict';

const bufferUtil = require('bufferutil');
const crypto = require('crypto');

const source = crypto.randomBytes(10);
const mask = crypto.randomBytes(4);

// Masks the source in-place by using source as the output buffer
bufferUtil.mask(source, mask, source, 0, source.length);

The bufferUtil.unmask() function unmasks a buffer using a provided masking-key according to the WebSocket protocol.

Note: To maximize performance, parameters are not validated. You must ensure all arguments are correct before calling the function.

Arguments:

• buffer: The buffer to unmask.
• mask: A buffer representing the 4-byte masking-key.

'use strict';

const bufferUtil = require('bufferutil');
const crypto = require('crypto');

const buffer = crypto.randomBytes(10);
const mask = crypto.randomBytes(4);

bufferUtil.unmask(buffer, mask);