Connection failed: Failed to decode base64

[demienYu]

From time 2 time i see this error.
Call stack:
Error: MongoError: "Connection failed: Failed to decode base64."
at MongoClient.connect (https://deno.land/x/[email protected]/src/client.ts:46:13)

my code looks like this:

export { MongoClient } from "https://deno.land/x/[email protected]/mod.ts"
const client = new MongoClient()
const options = {
servers: [{host: MONGO_HOST, port: MONGO_PORT}],
credential: {username: MONGO_USER, password: MONGO_PWD, db: 'admin', mechanism: 'SCRAM-SHA-1'},
db: 'mydb'
}
await client.connect(options) // this line causes error

[markwylde]

I'm getting this too periodically. I wonder if it's anything to do with this:
denoland/deno#19546

The full error I get is:

error: InvalidCharacterError: Failed to decode base64
  const binString = atob(b64);
                    ^
    at atob (ext:deno_web/05_base64.js:28:16)
    at Module.decode (https://deno.land/std@0.202.0/encoding/base64.ts:138:21)
    at continueScramConversation (file:///testproject/mongo/src/auth/scram.ts:196:11)
    at eventLoopTick (ext:core/01_core.js:178:11)
    at async Cluster.authenticateToServer (file:///testproject/mongo/src/cluster.ts:86:7)
    at async Promise.all (index 0)
    at async Cluster.authenticate (file:///testproject/mongo/src/cluster.ts:55:23)
    at async MongoClient.connect (file:///testproject/mongo/src/client.ts:37:7)
    at async createDatabase (file:///testproject/lib/utils/createDatabase.ts:25:3)

[markwylde]

I've tried using a custom base64 locally and it seems to have solved the issues for me:
#406

Obviously not a long term solution, but maybe it will work until the deno issue is resolved.

[markwylde]

The script below would reliably recreate the error at the time I was looking at this last year:

import { MongoClient } from '../mod.ts';

for (let x = 0; x < 100000; x++) {
  const client = new MongoClient();

  const url = `mongodb://testadmin1:testpass1@localhost:27017?directConnection=true`
  console.log('url:', url);
  await client.connect(url);

  await client.close()
  console.log('');
}

Running it now, on the latest main, I can no longer recreate the issue.

I believe this is because we are no longer using atob and are now using the base64 std library.