Making credentialed requests with Bokeh AjaxDataSource

I have a plot set up to use an AjaxDataSource. This is working pretty well in my local development, and was working as deployed in my Kubernetes cluster. However, after I added HTTPS and Google IAP (Identity-Aware Proxy) to my plotting app, all of the requests to the data-url for my AjaxDataSource are rejected by the Google IAP service.

I have run into this issue in the past with other AJAX requests to Google IAP-protected services, and resolved it by setting {withCredentials: true} in my axios requests. However, I do not have this option while working with Bokeh's AjaxDataSource. How do I get BokehJS to pass the cookies to my service in the AjaxDataSource?

Thanks to bigreddot for pointing me in the right direction. I was able to build a custom extension that did what I needed. Here's the source code for that extension:

from bokeh.models import AjaxDataSource
from bokeh.util.compiler import TypeScript

TS_CODE = """
import {AjaxDataSource} from "models/sources";

export class CredentialedAjaxDataSource extends AjaxDataSource {

    prepare_request(): XMLHttpRequest {
        const xhr = new XMLHttpRequest();
        xhr.open(this.method, this.data_url, true);
        xhr.withCredentials = true;
        xhr.setRequestHeader("Content-Type", this.content_type);

        const http_headers = this.http_headers;
        for (const name in http_headers) {
          const value = http_headers[name];
          xhr.setRequestHeader(name, value)
        }
        return xhr;
    }
}
"""


class CredentialedAjaxDataSource(AjaxDataSource):

    __implementation__ = TypeScript(TS_CODE)

Bokeh extensions documentation: https://docs.bokeh.org/en/latest/docs/user_guide/extensions.html