org.elasticsearch.search.fetch.subphase.highlight.HighlightPhase Maven / Gradle / Ivy
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.search.fetch.subphase.highlight;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.Query;
import org.elasticsearch.index.mapper.KeywordFieldMapper;
import org.elasticsearch.index.mapper.MappedFieldType;
import org.elasticsearch.index.mapper.TextFieldMapper;
import org.elasticsearch.search.fetch.FetchContext;
import org.elasticsearch.search.fetch.FetchSubPhase;
import org.elasticsearch.search.fetch.FetchSubPhaseProcessor;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.function.Function;
public class HighlightPhase implements FetchSubPhase {
private final Map highlighters;
public HighlightPhase(Map highlighters) {
this.highlighters = highlighters;
}
@Override
public FetchSubPhaseProcessor getProcessor(FetchContext context) {
if (context.highlight() == null) {
return null;
}
return getProcessor(context, context.highlight(), context.parsedQuery().query());
}
public FetchSubPhaseProcessor getProcessor(FetchContext context, SearchHighlightContext highlightContext, Query query) {
Map sharedCache = new HashMap<>();
Map> contextBuilders = contextBuilders(
context,
highlightContext,
query,
sharedCache
);
return new FetchSubPhaseProcessor() {
@Override
public void setNextReader(LeafReaderContext readerContext) {
}
@Override
public void process(HitContext hitContext) throws IOException {
Map highlightFields = new HashMap<>();
for (String field : contextBuilders.keySet()) {
FieldHighlightContext fieldContext = contextBuilders.get(field).apply(hitContext);
Highlighter highlighter = getHighlighter(fieldContext.field);
HighlightField highlightField = highlighter.highlight(fieldContext);
if (highlightField != null) {
// Note that we make sure to use the original field name in the response. This is because the
// original field could be an alias, and highlighter implementations may instead reference the
// concrete field it points to.
highlightFields.put(field, new HighlightField(field, highlightField.fragments()));
}
}
hitContext.hit().highlightFields(highlightFields);
}
};
}
private Highlighter getHighlighter(SearchHighlightContext.Field field) {
String highlighterType = field.fieldOptions().highlighterType();
if (highlighterType == null) {
highlighterType = "unified";
}
Highlighter highlighter = highlighters.get(highlighterType);
if (highlighter == null) {
throw new IllegalArgumentException("unknown highlighter type [" + highlighterType + "] for the field [" + field.field() + "]");
}
return highlighter;
}
private Map> contextBuilders(
FetchContext context,
SearchHighlightContext highlightContext,
Query query,
Map sharedCache
) {
Map> builders = new LinkedHashMap<>();
for (SearchHighlightContext.Field field : highlightContext.fields()) {
Highlighter highlighter = getHighlighter(field);
Collection fieldNamesToHighlight = context.getSearchExecutionContext().getMatchingFieldNames(field.field());
if (highlightContext.forceSource(field)) {
if (context.getSearchExecutionContext().isSourceEnabled() == false) {
throw new IllegalArgumentException("source is forced for fields " + fieldNamesToHighlight + " but _source is disabled");
}
}
boolean fieldNameContainsWildcards = field.field().contains("*");
for (String fieldName : fieldNamesToHighlight) {
MappedFieldType fieldType = context.getSearchExecutionContext().getFieldType(fieldName);
// We should prevent highlighting if a field is anything but a text, match_only_text,
// or keyword field.
// However, someone might implement a custom field type that has text and still want to
// highlight on that. We cannot know in advance if the highlighter will be able to
// highlight such a field and so we do the following:
// If the field is only highlighted because the field matches a wildcard we assume
// it was a mistake and do not process it.
// If the field was explicitly given we assume that whoever issued the query knew
// what they were doing and try to highlight anyway.
if (fieldNameContainsWildcards) {
if (fieldType.typeName().equals(TextFieldMapper.CONTENT_TYPE) == false
&& fieldType.typeName().equals(KeywordFieldMapper.CONTENT_TYPE) == false
&& fieldType.typeName().equals("match_only_text") == false) {
continue;
}
if (highlighter.canHighlight(fieldType) == false) {
continue;
}
}
Query highlightQuery = field.fieldOptions().highlightQuery();
boolean forceSource = highlightContext.forceSource(field);
builders.put(
fieldName,
hc -> new FieldHighlightContext(
fieldType.name(),
field,
fieldType,
context,
hc,
highlightQuery == null ? query : highlightQuery,
forceSource,
sharedCache
)
);
}
}
return builders;
}
}