Promise is never resolved when a server is down

[igor-lemon]

New Issue Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am not just asking a question.
• [x] I have searched through existing issues.
• [x] I can reproduce the issue with the latest versions of Parse Server and the Parse JS SDK.

Issue Description

The Promise from RESTController will never resolved when a server is down.

Steps to reproduce

Set some wrong URL as parse server url , parse.serverURL = 'https://some-wrong-site.com' Call

 const parseConfig = await Parse.Config.get()

Actual Outcome

The promise will never resolve.

Expected Outcome

The promise should be rejected.

Environment

Client

• Parse JS SDK version: 3.3.1

[parse-github-assistant[bot]]

Thanks for opening this issue!

• 🚀 You can help us to fix this issue faster by opening a pull request with a failing test. See our Contribution Guide for how to make a pull request, or read our New Contributor's Guide if this is your first time contributing.

[mtrezza]

What would be the expectation? To reject the promise after a timeout? I would assume the JS SDK already has a retry/timeout mechanism in place in case of bad network connection.

[igor-lemon]

Yep, I think we should make a few retries (if I remember 5 by default) but after the promise should be rejected. We have infinity waiting at the moment.

I think it related with if (xhr.readyState !== 4 || handled || xhr._aborted) condition. We have xhr.readyState === 1 and just exit from the handler and after we don't make any repeat attempts. I solved it at the local build when reject the promise at RESTControlle.js

 if (xhr.readyState !== 4 || handled || xhr._aborted) {
   promise.reject(xhr);
 }

[mtrezza]

Sounds reasonable. Do you think you can submit a PR with a test and a fix for this?

[igor-lemon]

Yep. I'll try to do it today

[igor-lemon]

Hi, @mtrezza! Will you check the PR?

[mtrezza]

Sure, feel free to request a review inside the PR anytime.