/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* 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
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.rest.action.search;
import org.apache.lucene.search.Explanation;
import org.elasticsearch.action.explain.ExplainRequest;
import org.elasticsearch.action.explain.ExplainResponse;
import org.elasticsearch.client.node.NodeClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.index.get.GetResult;
import org.elasticsearch.index.query.QueryBuilder;
import org.elasticsearch.rest.BaseRestHandler;
import org.elasticsearch.rest.BytesRestResponse;
import org.elasticsearch.rest.RestController;
import org.elasticsearch.rest.RestRequest;
import org.elasticsearch.rest.RestResponse;
import org.elasticsearch.rest.action.RestActions;
import org.elasticsearch.rest.action.RestBuilderListener;
import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
import java.io.IOException;
import static org.elasticsearch.rest.RestRequest.Method.GET;
import static org.elasticsearch.rest.RestRequest.Method.POST;
import static org.elasticsearch.rest.RestStatus.NOT_FOUND;
import static org.elasticsearch.rest.RestStatus.OK;
/**
* Rest action for computing a score explanation for specific documents.
*/
public class RestExplainAction extends BaseRestHandler {
public RestExplainAction(Settings settings, RestController controller) {
super(settings);
controller.registerHandler(GET, "/{index}/{type}/{id}/_explain", this);
controller.registerHandler(POST, "/{index}/{type}/{id}/_explain", this);
}
@Override
public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
final ExplainRequest explainRequest = new ExplainRequest(request.param("index"), request.param("type"), request.param("id"));
explainRequest.parent(request.param("parent"));
explainRequest.routing(request.param("routing"));
explainRequest.preference(request.param("preference"));
String queryString = request.param("q");
request.withContentOrSourceParamParserOrNull(parser -> {
if (parser != null) {
explainRequest.query(RestActions.getQueryContent(parser));
} else if (queryString != null) {
QueryBuilder query = RestActions.urlParamsToQueryBuilder(request);
explainRequest.query(query);
}
});
if (request.param("fields") != null) {
throw new IllegalArgumentException("The parameter [fields] is no longer supported, " +
"please use [stored_fields] to retrieve stored fields");
}
String sField = request.param("stored_fields");
if (sField != null) {
String[] sFields = Strings.splitStringByCommaToArray(sField);
if (sFields != null) {
explainRequest.storedFields(sFields);
}
}
explainRequest.fetchSourceContext(FetchSourceContext.parseFromRestRequest(request));
return channel -> client.explain(explainRequest, new RestBuilderListener<ExplainResponse>(channel) {
@Override
public RestResponse buildResponse(ExplainResponse response, XContentBuilder builder) throws Exception {
builder.startObject();
builder.field(Fields._INDEX, response.getIndex())
.field(Fields._TYPE, response.getType())
.field(Fields._ID, response.getId())
.field(Fields.MATCHED, response.isMatch());
if (response.hasExplanation()) {
builder.startObject(Fields.EXPLANATION);
buildExplanation(builder, response.getExplanation());
builder.endObject();
}
GetResult getResult = response.getGetResult();
if (getResult != null) {
builder.startObject(Fields.GET);
response.getGetResult().toXContentEmbedded(builder, request);
builder.endObject();
}
builder.endObject();
return new BytesRestResponse(response.isExists() ? OK : NOT_FOUND, builder);
}
private void buildExplanation(XContentBuilder builder, Explanation explanation) throws IOException {
builder.field(Fields.VALUE, explanation.getValue());
builder.field(Fields.DESCRIPTION, explanation.getDescription());
Explanation[] innerExps = explanation.getDetails();
if (innerExps != null) {
builder.startArray(Fields.DETAILS);
for (Explanation exp : innerExps) {
builder.startObject();
buildExplanation(builder, exp);
builder.endObject();
}
builder.endArray();
}
}
});
}
static class Fields {
static final String _INDEX = "_index";
static final String _TYPE = "_type";
static final String _ID = "_id";
static final String MATCHED = "matched";
static final String EXPLANATION = "explanation";
static final String VALUE = "value";
static final String DESCRIPTION = "description";
static final String DETAILS = "details";
static final String GET = "get";
}
}