package org.codelibs.fess.cors;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public abstract class CorsHandler {

    protected static final String ACCESS_CONTROL_ALLOW_ORIGIN = "Access-Control-Allow-Origin";

    protected static final String ACCESS_CONTROL_ALLOW_HEADERS = "Access-Control-Allow-Headers";

    protected static final String ACCESS_CONTROL_ALLOW_METHODS = "Access-Control-Allow-Methods";

* `expose_headers` - 指示可以被浏览器访问的响应头。默认为 `[]`。
* `max_age` - 设定浏览器缓存 CORS 响应的最长时间，单位是秒。默认为 `600`。

中间件响应两种特定类型的 HTTP 请求……

### CORS 预检请求

这是些带有 `Origin` 和 `Access-Control-Request-Method` 请求头的 `OPTIONS` 请求。

在这种情况下，中间件将拦截传入的请求并进行响应，出于提供信息的目的返回一个使用了适当的 CORS headers 的 `200` 或 `400` 响应。

### 简单请求

    this.supportsFastOffset = supportsFastOffset;
  }

  /**
   * Returns, conceptually, "origin + distance", or equivalently, the result of calling {@link
   * #next} on {@code origin} {@code distance} times.
   */
  C offset(C origin, long distance) {
    C current = origin;
    checkNonnegative(distance, "distance");
    for (long i = 0; i < distance; i++) {
      current = next(current);

                    String origin_server = handle.getServer();
                    CIFSContext origin_ctx = handle.getTransportContext();

                    for ( int i = 0; i < sids.length; i++ ) {
                        sids[ i ] = new SID(rpc.sids.sids[ i ].sid, 0, null, null, false);
                        sids[ i ].origin_server = origin_server;
                        sids[ i ].origin_ctx = origin_ctx;
                    }

  Set<E> inEdges();

  Set<E> outEdges();

  /**
   * Returns the set of edges connecting the origin node to {@code node}. For networks without
   * parallel edges, this set cannot be of size greater than one.
   */
  Set<E> edgesConnecting(N node);

  /**
   * Returns the node that is adjacent to the origin node along {@code edge}.
   *
   * <p>In the directed case, {@code edge} is assumed to be an outgoing edge.
   */

    void resolveWeak () {
        if ( this.origin_server != null ) {
            try {
                resolve(this.origin_server, this.origin_ctx);
            }
            catch ( IOException ioe ) {
                log.debug("Failed to resolve SID", ioe);
            }
            finally {
                this.origin_server = null;
                this.origin_ctx = null;
            }
        }
    }

  V removeSuccessor(N node);

  /**
   * Add {@code node} as a predecessor to the origin node. In the case of an undirected graph, it
   * also becomes a successor. Associates {@code value} with the edge connecting the two nodes.
   */
  void addPredecessor(N node, V value);

  /**
   * Add {@code node} as a successor to the origin node. In the case of an undirected graph, it also

```
curl http://minio1:9001/minio/health/cluster
HTTP/1.1 503 Service Unavailable
Accept-Ranges: bytes
Content-Length: 0
Server: MinIO
Vary: Origin
X-Amz-Bucket-Region: us-east-1
X-Minio-Write-Quorum: 3
X-Amz-Request-Id: 16239D6AB80EBECF
X-Xss-Protection: 1; mode=block
Date: Tue, 21 Jul 2020 00:36:14 GMT
```

### Cluster-readable probe

        return when (symbol.origin) {
            KtSymbolOrigin.SOURCE_MEMBER_GENERATED -> true
            else -> false
        }
    }

    private fun isOrdinarySymbolWithSource(symbol: KtSymbol): Boolean {
        return symbol.origin == KtSymbolOrigin.SOURCE
                || symbol.firSymbol.fir.origin == FirDeclarationOrigin.ScriptCustomization.ResultProperty
    }

		if !versions.Contains(gvk.KubernetesGateway.Version) {
			origin := legacykube.Origin{
				Type: gvk.CustomResourceDefinition,
				FullName: resource.FullName{
					Namespace: resource.Namespace(r.Namespace),
					Name:      resource.LocalName(r.Name),
				},
				ResourceVersion: resource.Version(r.ResourceVersion),
			}
			r := &resource.Instance{
				Origin: &origin,
			}