refactor(NODE-5953): move promisifying of randomBytes to utils (#3999)

Author: alenakhineika

Diff for: src/cmap/auth/mongodb_aws.ts

@@ -1,6 +1,4 @@
-import * as crypto from 'crypto';
 import * as process from 'process';
-import { promisify } from 'util';
 
 import type { Binary, BSONSerializeOptions } from '../../bson';
 import * as BSON from '../../bson';
@@ -11,7 +9,7 @@ import {
   MongoMissingCredentialsError,
   MongoRuntimeError
 } from '../../error';
-import { ByteUtils, maxWireVersion, ns, request } from '../../utils';
+import { ByteUtils, maxWireVersion, ns, randomBytes, request } from '../../utils';
 import { type AuthContext, AuthProvider } from './auth_provider';
 import { MongoCredentials } from './mongo_credentials';
 import { AuthMechanism } from './providers';
@@ -59,11 +57,9 @@ interface AWSSaslContinuePayload {
 export class MongoDBAWS extends AuthProvider {
   static credentialProvider: ReturnType<typeof getAwsCredentialProvider>;
   provider?: () => Promise<AWSCredentials>;
-  randomBytesAsync: (size: number) => Promise<Buffer>;
 
   constructor() {
     super();
-    this.randomBytesAsync = promisify(crypto.randomBytes);
     MongoDBAWS.credentialProvider ??= getAwsCredentialProvider();
 
     let { AWS_STS_REGIONAL_ENDPOINTS = '', AWS_REGION = '' } = process.env;
@@ -131,7 +127,7 @@ export class MongoDBAWS extends AuthProvider {
         : undefined;
 
     const db = credentials.source;
-    const nonce = await this.randomBytesAsync(32);
+    const nonce = await randomBytes(32);
 
     const saslStart = {
       saslStart: 1,

Diff for: src/cmap/auth/scram.ts

@@ -1,14 +1,13 @@
 import { saslprep } from '@mongodb-js/saslprep';
 import * as crypto from 'crypto';
-import { promisify } from 'util';
 
 import { Binary, type Document } from '../../bson';
 import {
   MongoInvalidArgumentError,
   MongoMissingCredentialsError,
   MongoRuntimeError
 } from '../../error';
-import { ns } from '../../utils';
+import { ns, randomBytes } from '../../utils';
 import type { HandshakeDocument } from '../connect';
 import { type AuthContext, AuthProvider } from './auth_provider';
 import type { MongoCredentials } from './mongo_credentials';
@@ -18,11 +17,10 @@ type CryptoMethod = 'sha1' | 'sha256';
 
 class ScramSHA extends AuthProvider {
   cryptoMethod: CryptoMethod;
-  randomBytesAsync: (size: number) => Promise<Buffer>;
+
   constructor(cryptoMethod: CryptoMethod) {
     super();
     this.cryptoMethod = cryptoMethod || 'sha1';
-    this.randomBytesAsync = promisify(crypto.randomBytes);
   }
 
   override async prepare(
@@ -35,7 +33,7 @@ class ScramSHA extends AuthProvider {
       throw new MongoMissingCredentialsError('AuthContext must provide credentials.');
     }
 
-    const nonce = await this.randomBytesAsync(24);
+    const nonce = await randomBytes(24);
     // store the nonce for later use
     authContext.nonce = nonce;
 

Diff for: src/utils.ts

@@ -4,6 +4,7 @@ import * as http from 'http';
 import { clearTimeout, setTimeout } from 'timers';
 import * as url from 'url';
 import { URL } from 'url';
+import { promisify } from 'util';
 
 import { type Document, ObjectId, resolveBSONOptions } from './bson';
 import type { Connection } from './cmap/connection';
@@ -1292,3 +1293,5 @@ export function promiseWithResolvers<T>() {
   });
   return { promise, resolve, reject } as const;
 }
+
+export const randomBytes = promisify(crypto.randomBytes);