Expose Response Headers on ArcgisError object for status != 200

[efbenson]

Describe the problem

We had a support request with AGOL and they need the response headers, there is no way to get them from this package without patching the module (which we are attempting) When a status code 500/503 (non 200) error is returned the response headers are not exposed via the error object.

Describe the proposed solution

We are seeing if this will work (in my simulations it appeared to). Tweaking this code here seemed to do it.

https://github.com/Esri/arcgis-rest-js/blob/main/packages/arcgis-rest-request/src/request.ts#L424

            const { status, statusText, headers } = response;
            const { message, details } = jsonError.error;
            const formattedMessage = `${message}. ${
              details ? details.join(" ") : ""
            }`.trim();

            throw new ArcGISRequestError(
              formattedMessage,
              `HTTP ${status} ${statusText}`,
              {body: jsonError, headers: [...headers]},
              url,
              options
            );
          })

Alternatives considered

No response

Additional Information

No response

[gavinr-maps]

@efbenson thank you for logging this issue. This request seems reasonable to me. @patrickarlt @dbouwman do you have any thoughts on this request? Just to be clear, the proposed change is to change/add this code:

... at this location: https://github.com/Esri/arcgis-rest-js/blob/main/packages/arcgis-rest-request/src/request.ts#L424

[patrickarlt]

This looks good do me if someone wants to do a PR.

[efbenson]

Looking into this further there is a couple cases where they would have to be trapped and exposed. My original change and the condition under it:
https://github.com/Esri/arcgis-rest-js/blob/main/packages/arcgis-rest-request/src/request.ts#L420

That was not hard to patch, the hard part is when the wrapped response comes through on a 200 status code but has the error in the response payload:
https://github.com/Esri/arcgis-rest-js/blob/main/packages/arcgis-rest-request/src/request.ts#L458

For this case the response object is not available since it is in the previous promise scope and not passed through to this promise that only receives the response body. Probably the simplest way to clean that up would be to refactor it to use await and try catches to keep the response object in scope. But it's a good bit of work for me to just patch into the module in production and we are not up for the risk.

[gavinr-maps]

Hi @efbenson, we think it might be easiest to create a variable up higher level in the scope (higher in the file) called something like originalResponseObject, and set that right before the switch/case block, so that then you can read from that variable within the .then(.. starting on line 476. Will that work for you?