org.elasticsearch.rest.BaseRestHandler Maven / Gradle / Ivy
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* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.rest;
import org.elasticsearch.action.*;
import org.elasticsearch.client.Client;
import org.elasticsearch.client.FilterClient;
import org.elasticsearch.common.ParseFieldMatcher;
import org.elasticsearch.common.component.AbstractComponent;
import org.elasticsearch.common.settings.Settings;
import java.util.Set;
/**
* Base handler for REST requests.
*
* This handler makes sure that the headers & context of the handled {@link RestRequest requests} are copied over to
* the transport requests executed by the associated client. While the context is fully copied over, not all the headers
* are copied, but a selected few. It is possible to control what headers are copied over by registering them using
* {@link org.elasticsearch.rest.RestController#registerRelevantHeaders(String...)}
*/
public abstract class BaseRestHandler extends AbstractComponent implements RestHandler {
private final RestController controller;
private final Client client;
protected final ParseFieldMatcher parseFieldMatcher;
protected BaseRestHandler(Settings settings, RestController controller, Client client) {
super(settings);
this.controller = controller;
this.client = client;
this.parseFieldMatcher = new ParseFieldMatcher(settings);
}
@Override
public final void handleRequest(RestRequest request, RestChannel channel) throws Exception {
handleRequest(request, channel, new HeadersAndContextCopyClient(client, request, controller.relevantHeaders()));
}
protected abstract void handleRequest(RestRequest request, RestChannel channel, Client client) throws Exception;
@Override
public boolean canTripCircuitBreaker() {
return true;
}
static final class HeadersAndContextCopyClient extends FilterClient {
private final RestRequest restRequest;
private final Set headers;
HeadersAndContextCopyClient(Client in, RestRequest restRequest, Set headers) {
super(in);
this.restRequest = restRequest;
this.headers = headers;
}
private static void copyHeadersAndContext(ActionRequest actionRequest, RestRequest restRequest, Set headers) {
for (String usefulHeader : headers) {
String headerValue = restRequest.header(usefulHeader);
if (headerValue != null) {
actionRequest.putHeader(usefulHeader, headerValue);
}
}
actionRequest.copyContextFrom(restRequest);
}
@Override
protected > void doExecute(Action action, Request request, ActionListener listener) {
copyHeadersAndContext(request, restRequest, headers);
super.doExecute(action, request, listener);
}
}
}