How to score based on number of substring occurrences within a field in ElasticSearch - elasticsearch

Question

I have an ElasticSearch document setup like so
{
metadata: {
content: "",
other_fields: ...
},
other_fields: ...
}
and am querying the content field like so
{
"function_score": {
"query": {
"multi-match": {
"query": "searchTerm",
"fields": ["content", "other_fields", ...]
}
},
"functions": [
{
"weight": {
"filter": {
"match": {
"metadata.content": {
"query": "searchTerm"
},
"weight": 3
}
}
},
{
other weight functions for the other fields with custom score values
}
],
"boost_mode": "replace",
"score_mode": "sum"
}
}
This works great calculating the score for all of the fields based on matches (including the content field). However, I want to multiply the content field score by the number of occurrences of the search term in the content field.
For example when I search for "test" in the doc below, the score is 3 but I want it to be 9:
{
metadata: {
content: "test test test"
}
}
Any suggestions on how I can do this?

Answer 1

I could not replicate your query -- too many typos/syntax issues. Here's what I could reconstruct:
Let's first create some sample docs
POST metaa/_doc
{
"metadata": {
"content": "test"
}
}
POST metaa/_doc
{
"metadata": {
"content": "test test"
}
}
POST metaa/_doc
{
"metadata": {
"content": "test test test"
}
}
then querying & using script_score, inspired by this cool answer:
GET metaa/_search
{
"query": {
"function_score": {
"query": {
"multi_match": {
"query": "test",
"fields": [
"metadata.content",
"other_fields"
]
}
},
"functions": [
{
"script_score": {
"script": {
"source": """
def docval = doc['metadata.content.keyword'].value;
String temp = docval.replace('test', "");
return (docval.length() - temp.length()) / 4;
"""
}
},
"filter": {
"match": {
"metadata.content": {
"query": "test"
}
}
},
"weight": 3
}
],
"boost_mode": "replace",
"score_mode": "sum"
}
}
}
yielding
[
{
"_index":"metaa",
"_type":"_doc",
"_id":"suh763EBG_KW3EFnjwNq",
"_score":9.0,
"_source":{
"metadata":{
"content":"test test test"
}
}
},
{
"_index":"metaa",
"_type":"_doc",
"_id":"seh763EBG_KW3EFnewP6",
"_score":6.0,
"_source":{
"metadata":{
"content":"test test"
}
}
},
{
"_index":"metaa",
"_type":"_doc",
"_id":"s-h_63EBG_KW3EFnMQMU",
"_score":3.0,
"_source":{
"metadata":{
"content":"test"
}
}
}
]
_score = 9 -> 6 -> 3.
Note: you may want to perform some validity checks within the script (could be a simple try/catch). But that's an exercise for the reader.