RestHeadAction.java

package org.elasticsearch.rest.action.get;

import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.client.Client;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.bytes.BytesArray;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.rest.BaseRestHandler;
import org.elasticsearch.rest.BytesRestResponse;
import org.elasticsearch.rest.RestChannel;
import org.elasticsearch.rest.RestController;
import org.elasticsearch.rest.RestRequest;
import org.elasticsearch.rest.RestResponse;
import org.elasticsearch.rest.action.support.RestResponseListener;

import static org.elasticsearch.rest.RestRequest.Method.HEAD;
import static org.elasticsearch.rest.RestStatus.NOT_FOUND;
import static org.elasticsearch.rest.RestStatus.OK;

public abstract class RestHeadAction extends BaseRestHandler {

    public RestHeadAction(Settings settings, Client client) {
        super(settings, client);
    }

    public static class Source extends RestHeadAction {

        @Inject
        public Source(Settings settings, RestController controller, Client client) {
            super(settings, client);
            controller.registerHandler(HEAD, "/{index}/{type}/{id}/_source", this);
        }

        @Override
        protected void handleRequest(RestRequest request, RestChannel channel, Client client) throws Exception {
            getHandler(request, channel, client, false);
        }
    }

    public static class Document extends RestHeadAction {

        @Inject
        public Document(Settings settings, RestController controller, Client client) {
            super(settings, client);
            controller.registerHandler(HEAD, "/{index}/{type}/{id}", this);
        }

        @Override
        protected void handleRequest(RestRequest request, RestChannel channel, Client client) throws Exception {
            getHandler(request, channel, client, false);
        }
    }

    private static void getHandler(RestRequest request, RestChannel channel, Client client, final boolean source) {
        final GetRequest getRequest = new GetRequest(request.param("index"), request.param("type"), request.param("id"));
        getRequest.operationThreaded(true);
        getRequest.refresh(request.paramAsBoolean("refresh", getRequest.refresh()));
        getRequest.routing(request.param("routing"));  // order is important, set it after routing, so it will set the routing
        getRequest.parent(request.param("parent"));
        getRequest.preference(request.param("preference"));
        getRequest.realtime(request.paramAsBoolean("realtime", getRequest.realtime()));
        // don't get any fields back...
        getRequest.fields(Strings.EMPTY_ARRAY);
        // TODO we can also just return the document size as Content-Length
        client.get(getRequest, new RestResponseListener<GetResponse>(channel) {
            @Override
            public RestResponse buildResponse(GetResponse response) {
                if (!response.isExists()) {
                    return new BytesRestResponse(NOT_FOUND, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY);
                } else if (source && response.isSourceEmpty()) { // doc exists, but source might not
                    return new BytesRestResponse(NOT_FOUND, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY);
                } else {
                    return new BytesRestResponse(OK, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY);
                }
            }
        });
    }
}