tus: add onBeforeRequest option

[bedgerotto]

The onBeforeRequest callback cant be changed by Tus options after the changes on the issue #2518

In this case, I think that we could skip the default callback definition if the callbacck was passed through Tus options

[arturi]

@Acconut what do you think?

[Acconut]

It would be better if the withCredentials option keeps working, even if onBeforeRequest is supplied. This is possible, so I don't see a reason for this behavior as it could be very confusing for users. How about this code:

        uploadOptions.onBeforeRequest = (req) => {
          const xhr = req.getUnderlyingObject()
          xhr.withCredentials = !!opts.withCredentials

          if (typeof uploadOptions.onBeforeRequest !== 'function') {
            uploadOptions.onBeforeRequest(req)
          }
        } 

[bedgerotto]

In this case, I was overwriting onBeforeRequest to manually set xhr.withCredentials as true because, even I set withCredentials option on Tus configuration as true I still unable to send and receive cookies through subdomains.

Maybe, it's related with this another issue?(#2443 )

[Acconut]

I don't understand your last comment, to be honest. The code I posted above is not meant as a suggestion for how you can fix the issue in your application. It's a suggestion for how this PR should be implemented instead.

[bedgerotto]

Sorry, I got it wrong.

I'll try your suggestion and update this PR. Thanks

[Acconut]

Great! Let me know, if you made the changes, so I can review them, @bedgerotto!

[bedgerotto]

@Acconut I checked out your suggestion and it didn't work because it is overwriting the uploadOptions.onBeforeRequest and then trying to call the same method if it is not a function.

But, based on this approach I have tested the following code and it works well once it is attached on the received opts

uploadOptions.onBeforeRequest = (req) => {
    const xhr = req.getUnderlyingObject()
    xhr.withCredentials = !!opts.withCredentials

    if (typeof opts.onBeforeRequest === 'function') {
      opts.onBeforeRequest(req)
  }
}

[Acconut]

A test would be nice but that's up to the Uppy team to decide. From a tus-js-client POV, this looks good 👍

[goto-bus-stop]

thank you!