Set up basic scripted topic aggregation

For implementing NWBib topic search based on API 2.0

See hbz/nwbib#163

web/app/controllers/resources/Application.java

@@ -91,6 +91,8 @@
 	public static final String MEDIUM_FIELD = "medium.id";
 	/** The internal ES aggregation name for the owner facet. */
 	public static final String OWNER_AGGREGATION = "owner";
+	/** The internal ES aggregation name for the topics. */
+	public static final String TOPIC_AGGREGATION = "topic";
 	/** The internal ES field for subjects. */
 	public static final String SUBJECT_FIELD = "subject.componentList.id";
 	/** The internal ES field for contributing agents. */

web/app/controllers/resources/Index.java

@@ -5,35 +5,42 @@
 import static controllers.resources.Application.MEDIUM_FIELD;
 import static controllers.resources.Application.OWNER_AGGREGATION;
 import static controllers.resources.Application.SUBJECT_FIELD;
+import static controllers.resources.Application.TOPIC_AGGREGATION;
 import static controllers.resources.Application.TYPE_FIELD;
 import static org.elasticsearch.index.query.QueryBuilders.matchQuery;
 
 import java.net.InetAddress;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
 import org.apache.lucene.search.join.ScoreMode;
+import org.elasticsearch.action.admin.cluster.storedscripts.PutStoredScriptResponse;
 import org.elasticsearch.action.admin.indices.validate.query.ValidateQueryResponse;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.action.search.SearchRequestBuilder;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.SearchType;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.client.transport.TransportClient;
+import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.geo.GeoPoint;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.transport.InetSocketTransportAddress;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.query.BoolQueryBuilder;
 import org.elasticsearch.index.query.GeoDistanceQueryBuilder;
 import org.elasticsearch.index.query.GeoPolygonQueryBuilder;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.join.aggregations.ChildrenAggregationBuilder;
 import org.elasticsearch.join.query.JoinQueryBuilders;
+import org.elasticsearch.script.Script;
+import org.elasticsearch.script.ScriptType;
 import org.elasticsearch.search.SearchHit;
 import org.elasticsearch.search.SearchHits;
 import org.elasticsearch.search.aggregations.AggregationBuilder;
@@ -44,8 +51,10 @@
 import org.elasticsearch.transport.client.PreBuiltTransportClient;
 
 import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 
 import play.Logger;
+import play.Play;
 import play.cache.Cache;
 import play.libs.Json;
 
@@ -103,9 +112,10 @@
 	/**
 	 * The values supported for the `aggregations` query parameter.
 	 */
-	public static final List<String> SUPPORTED_AGGREGATIONS = Arrays.asList(
-			ISSUED_FIELD, SUBJECT_FIELD, TYPE_FIELD, MEDIUM_FIELD, OWNER_AGGREGATION,
-			AGENT_FIELD, SPATIAL_LABEL_FIELD, SPATIAL_GEO_FIELD, SUBJECT_ID_FIELD);
+	public static final List<String> SUPPORTED_AGGREGATIONS =
+			Arrays.asList(ISSUED_FIELD, SUBJECT_FIELD, TYPE_FIELD, MEDIUM_FIELD,
+					OWNER_AGGREGATION, AGENT_FIELD, SPATIAL_LABEL_FIELD,
+					SPATIAL_GEO_FIELD, SUBJECT_ID_FIELD, TOPIC_AGGREGATION);
 
 	/**
 	 * @param q The current query string
@@ -116,8 +126,9 @@ public String buildQueryString(String q, String... values) {
 		String fullQuery = q.isEmpty() ? "*" : "(" + q + ")";
 		for (int i = 0; i < values.length; i++) {
 			String fieldValue = values[i];
-			String fieldName = fieldValue.contains("http")
-					? QUERY_FIELDS[i].replace(".label", ".id") : QUERY_FIELDS[i];
+			String fieldName =
+					fieldValue.contains("http") ? QUERY_FIELDS[i].replace(".label", ".id")
+							: QUERY_FIELDS[i];
 			if (fieldName.toLowerCase().endsWith("date")
 					&& fieldValue.matches("(\\d{1,4}|\\*)-(\\d{1,4}|\\*)")) {
 				String[] fromTo = fieldValue.split("-");
@@ -200,7 +211,7 @@ public Index queryResources(String q, int from, int size, String sort,
 			}
 			if (!aggregations.isEmpty()) {
 				requestBuilder =
-						withAggregations(requestBuilder, aggregations.split(","));
+						withAggregations(client, requestBuilder, aggregations.split(","));
 			}
 			SearchResponse response = requestBuilder.execute().actionGet();
 			SearchHits hits = response.getHits();
@@ -359,11 +370,11 @@ public long getTotal() {
 		return total;
 	}
 
-	private static SearchRequestBuilder withAggregations(
+	private static SearchRequestBuilder withAggregations(Client client,
 			final SearchRequestBuilder searchRequest, String... fields) {
 		int defaultSize = 100;
 		Arrays.asList(fields).forEach(field -> {
-			if (field.equals("owner")) {
+			if (field.equals(OWNER_AGGREGATION)) {
 				AggregationBuilder ownerAggregation =
 						new ChildrenAggregationBuilder(Application.OWNER_AGGREGATION,
 								TYPE_ITEM)
@@ -374,6 +385,16 @@ private static SearchRequestBuilder withAggregations(
 				searchRequest
 						.addAggregation(AggregationBuilders.geohashGrid(SPATIAL_GEO_FIELD)
 								.field(SPATIAL_GEO_FIELD).precision(9));
+			} else if (field.equals(TOPIC_AGGREGATION) && !Play.isTest()) {
+				String lang = "painless";
+				String id = "topic-aggregation";
+				// TODO: store script only once, on startup?
+				PutStoredScriptResponse response = storeScript(client, lang, id);
+				if (response.isAcknowledged()) {
+					searchRequest.addAggregation(
+							AggregationBuilders.terms(TOPIC_AGGREGATION).script(new Script(
+									ScriptType.STORED, lang, id, Collections.emptyMap())));
+				}
 			} else {
 				boolean many = field.equals("publication.startDate");
 				searchRequest.addAggregation(AggregationBuilders.terms(field)
@@ -383,6 +404,19 @@ private static SearchRequestBuilder withAggregations(
 		return searchRequest;
 	}
 
+	private static PutStoredScriptResponse storeScript(Client client, String lang,
+			String id) {
+		String script = // TODO: use subject.componentList.label.raw
+				"String chain = \"\"; for(String id : doc['subject.componentList.id']) {"
+						+ "chain += \" \" + id} return chain.trim();";
+		ObjectNode scriptObject = Json.newObject();
+		scriptObject.putObject("script").put("lang", lang).put("source", script);
+		Logger.debug("Will store script: {}", scriptObject);
+		return client.admin().cluster().preparePutStoredScript().setId(id)
+				.setContent(new BytesArray(scriptObject.toString()), XContentType.JSON)
+				.get();
+	}
+
 	<T> T withClient(Function<Client, T> function) {
 		if (elasticsearchClient != null) {
 			return function.apply(elasticsearchClient);