Elasticsearch Highlight issue on aggregated fields - elasticsearch

Question

I am using ElasticSearch and want to get highlighted field on the aggregated result of the search query.
I do not want to get results of search query, so I kept the size to be 0 which only gives me aggregated results.
Now I want to apply highlighters on the aggregated results, but that is not working. I am using a term aggregator and a top-hits aggregator as the sub aggregator. In the ES docs they have mentioned top-hits aggregator supports highlighting.
My structure of query goes like this:
{
size:0,
query:{
.......
},
aggregation:{
name-of-agg:{
term:{
....
},
aggregation:{
name-of-sub-agg:{
top-hits:{
....
}
}
}
},
highlight:{
fields:{
fieldname:{
}
}
}
}
}

Answer 1

You have to set the highlight inside the top_hits aggregation properties (not inside of aggregation).
Here is a working minimal example:
echo create index
curl -XPUT 'http://127.0.0.1:9010/files?pretty=1' -d '
{
"settings": {
}
}'
echo create type
curl -XPUT 'http://127.0.0.1:9010/files/_mapping/file?pretty=1' -d'
{
"properties":{
"fileName":{
"type":"string",
"term_vector":"with_positions_offsets"
}
}
}
'
echo insert files
curl -XPUT 'http://127.0.0.1:9010/files/file/1?pretty=1' -d'
{
"fileName":"quick brown fox"
}
'
echo flush
curl -XPOST 'http://127.0.0.1:9010/files/_flush?pretty=1'
echo search brown tophits
curl -XGET 'http://127.0.0.1:9010/files/file/_search?pretty=1' -d '
{
"size" : 0,
"query":{
"match":{
"fileName":"brown"
}
},
"aggregations" : {
"docs" : {
"top_hits" : {
"highlight": {
"fields": {
"fileName": {}
}
}
}
}
}
}'