elasticsearch - get intermediate scores within 'function_score' - elasticsearch

Question

Here's my index
POST /blogs/1
{
"name" : "learn java",
"popularity" : 100
}
POST /blogs/2
{
"name" : "learn elasticsearch",
"popularity" : 10
}
My search query:
GET /blogs/_search
{
"query": {
"function_score": {
"query": {
"match": {
"name": "learn"
}
},
"script_score": {
"script": {
"source": "_score*(1+Math.log(1+doc['popularity'].value))"
}
}
}
}
}
which returns:
[
{
"_index": "blogs",
"_type": "1",
"_id": "AW5fxnperVbDy5wjSDBC",
"_score": 0.58024323,
"_source": {
"name": "learn elastic search",
"popularity": 100
}
},
{
"_index": "blogs",
"_type": "1",
"_id": "AW5fxqmL8cCMCxtBYOyC",
"_score": 0.43638366,
"_source": {
"name": "learn java",
"popularity": 10
}
}
]
Problem: I need to return an extra field in results which would give me raw score (just tf/idf which doesn't take popularity into account)
Things I have explored: script_fields (which doesn't give access to _score at fetch time.

Answer 1

The problem is in the way you are querying, which over-writes the _score variable. Instead if you use sort then _score isn't changed and can be pulled up within the same query.
You can try querying this way :
{
"query": {
"match": {
"name": "learn"
}
},
"sort": [
{
"_script": {
"type": "number",
"script": {
"lang": "painless",
"source": "_score*(1+Math.log(1+doc['popularity'].value))"
},
"order": "desc"
}
},
"_score"
]
}