import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

/**
 * Filter for handling Cross-Origin Resource Sharing (CORS) requests.
 * Processes CORS headers and handles preflight OPTIONS requests.
 */
public class CorsFilter implements Filter {

    /**
     * Creates a new instance of CorsFilter.
     */
    public CorsFilter() {
        // Default constructor
    }

     * CORS header for allowing credentials.
     */
    protected static final String ACCESS_CONTROL_ALLOW_CREDENTIALS = "Access-Control-Allow-Credentials";

    /**
     * CORS header for specifying cache duration for preflight requests.
     */
    protected static final String ACCESS_CONTROL_MAX_AGE = "Access-Control-Max-Age";

    /**
     * Processes the CORS request by setting appropriate headers.
     *

  
  To allow cgroups v1 with `kubeadm` and `kubelet` version `v1.35` or newer, you must:
  - Ignore the error from the SystemVerification preflight check by `kubeadm`.

- kubeadm: removed preflight check for nsenter on Linux nodes

- kubeadm: removed `socat` and `ebtables` from kubeadm preflight checks ([#127151](https://github.com/kubernetes/kubernetes/pull/127151), [@saschagrunert](https://github.com/saschagrunert)) [SIG Cluster Lifecycle]

- Kubeadm: Added support during the preflight check "CreateJob" of "kubeadm upgrade" to check if there are no nodes where a Pod can be scheduled. If there are none, show a warning and skip this preflight check. This can happen in single node clusters where the only node was drained. ([#124503](https://github.com/kubernetes/kubernetes/pull/124503), [@neolit123](https:/...

- Kubeadm: switch the preflight check (called 'Swap') that verifies if swap is enabled on Linux hosts to report a warning instead of an error. This is related to the graduation of the NodeSwap feature gate in the kubelet to Beta and being enabled by default in 1.23 - allows swap support on Linux hosts. In the next release of kubeadm (1.24) the preflight check will be removed, thus we recommend that you stop using it - e.g. via `--ignore-preflight-errors`...

- Kubeadm: during the preflight check "CreateJob" of "kubeadm upgrade", check if there are no nodes where a Pod can schedule. If there are none, show a warning and skip this preflight check. This can happen in single node clusters where the only node was drained. ([#124570](https://github.com/kubernetes/kubernetes/pull/124570), [@neolit123](https://gi...

* kubeadm now produces error during preflight checks if swap is enabled. Users, who can setup kubelet to run in unsupported environment with enabled swap, will be able to skip that preflight check. ([#55399](https://github.com/kubernetes/kubernetes/pull/55399), [@kad](https://github.com/kad))

### Other (Cleanup or Flake)

- Kubeadm: removed `socat` and `ebtables` from kubeadm preflight checks ([#127415](https://github.com/kubernetes/kubernetes/pull/127415), [@saschagrunert](https://github.com/saschagrunert)) [SIG Cluster Lifecycle]

## Dependencies

### Added
_Nothing has changed._