Preserving Source IP and webdav request conflict

Describe your Issue

Hi,

I am trying to set up WebDAV for Zotero, but I am running into an issue with ingress and CORS settings.

• The deployment uses image.flavor: apache.
• I followed the recommended settings: preserve the source IP and support CORS.
• My current ingress annotations:

ingress:
  annotations:
   nginx.ingress.kubernetes.io/enable-cors: "true"
   nginx.ingress.kubernetes.io/cors-allow-headers: "X-Forwarded-For"

With this config, when Zotero or I use an OPTIONS request (for WebDAV capability check), the response is processed directly by the ingress (HTTP 204), and the request does not reach the backend (Nextcloud).
As a result, Zotero cannot detect the WebDAV capabilities correctly, since the WebDAV-specific headers (like DAV:) are not provided as expected. Though I can correctly synchronize webdav files, zotero must firstly do this step for checking before synchronizing.

Here is the curl test:

···bash
curl -i -X OPTIONS https://NEXTCLOUD-URL/remote.php/dav/files/USERNAME
···
Output

HTTP/2 204
...
access-control-allow-methods: GET, PUT, POST, DELETE, PATCH, OPTIONS, PROPFIND, PROPPATCH, COPY, MOVE, LOCK, UNLOCK
access-control-allow-headers: X-Forwarded-For
...

Question:
How should I configure ingress-nginx so that:

• CORS is enabled,

• Source IP is preserved,

• AND the OPTIONS/WebDAV capability requests are actually forwarded to the backend (not intercepted by the ingress), so the WebDAV headers are correctly returned?

Any help is much appreciated!

Describe your Environment

• Kubernetes distribution: rke2

• Helm Version (or App that manages helm): it's independent to helm version

• Helm Chart Version: it's independent to helm chart version

• values.yaml:

# paste your values.yaml (anonymize any sensitive data)

Additional context, if any

Start with the ingress annotations and the curl OPTIONS request shown in the issue, then trace how ingress-nginx handles CORS preflight requests for the Nextcloud WebDAV endpoint. Done means identifying a configuration that preserves the source IP, keeps CORS enabled, forwards OPTIONS to the backend, and returns the expected WebDAV headers.