Deprecation warning for listening on Db class events

[Moumouls]

New Issue Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.
• I can reproduce the issue with the latest version of Parse Server.

Issue Description

Lot of warning from mongodb package after upgrade from #7322

Steps to reproduce

Install parse from master
Run parse server

At each server start parse server log.

(node:13319) DeprecationWarning: Listening to events on the Db class has been deprecated and will be removed in the next major version.

Actual Outcome

Too many logs from mongodb pkg

(node:13319) DeprecationWarning: Listening to events on the Db class has been deprecated and will be removed in the next major version.

Expected Outcome

No logs

Failing Test Case / Pull Request

• 🤩 I submitted a PR with a fix and a test case.
• 🧐 I submitted a PR with a failing test case.

Environment

Server

• Parse Server version: current master
• Operating system: macOS
• Local or remote host (AWS, Azure, Google Cloud, Heroku, Digital Ocean, etc): local

Database

• System (MongoDB or Postgres): Mongo
• Database version: 4.4.X
• Local or remote host (MongoDB Atlas, mLab, AWS, Azure, Google Cloud, etc): local

Client

• SDK (iOS, Android, JavaScript, PHP, Unity, etc): none
• SDK version: node

Logs

[Moumouls]

downgrade to mongo 3.6.3 fix the issue, but it's just a temporary fix. I do not know which Parse Server code use DB listening events. @dplewis @mtrezza if you have an idea 🙂

[mtrezza]

Thanks for reporting!

Can you please fill out the versions in the template so we know in what environment (Node / MongoDB driver) you are experiencing this issue?

This deprecation warning comes from Node, not from the MongoDB driver?

[Moumouls]

@mtrezza it seems to come from the native mongo driver: https://stackoverflow.com/questions/66190532/deprecationwarning-listening-to-events-on-the-db-class-has-been-deprecated-and

All version >3.6.3 seems to raise this log.

[mtrezza]

Thanks for the details, this seems to explain the fix needed:

Db is no longer the place to listen to events, you should listen to your MongoClient instead like so:

const client = new MongoClient(…)
client.on(‘Event name I want to listen too’, () => {…})
await client.connect()

The reason for this style is because by registering your listeners before connecting you can be sure that you’re able to capture every event that is triggered

A search in the Parse Server code base should reveal the places where listening to DB has to be changed.

[mtrezza]

I classified this as bug with severity S4 (small/trivial):

• Using deprecated APIs should be avoided, therefore it is considered a bug
• Because it is only a warning without any current functional effects, it is only considered a small / trivial bug

[rocxteady]

Wasn't this fixed with: #7626? Why is it open still?