In Elastic search, can we change the names of retrieved fields of searched response dynamically, like mongoDB projection?

Elastic Stack Elasticsearch
1

When I query on Elasticsearch (ES) to get some data, I get it in following format:

Response:

"hits" : [
      {
        "_index" : "testpoc",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "ext" : [
            {
              "sii" : {
                "1" : {
                  "csp" : 19.0
                }
              }
            }
          ],
          "pld" : "PDyfJ3MypQYK4MA2222",
          "tms" : "2022-11-29T11:15:02+0000"
        }
      }]

Current query:

GET testpoc/_search
{
   "_source": [
    "tms",
    "pld",
    "ext.sii.1.csp"
  ]
}

I want to receive response in a particular format, rather than getting "ext[0].sii.1.csp", I want to map it into "csp" field.

Note: "ext[0].sii.1.csp" is dynamic, I can query to get some "ext[0].sii.1.xyz", and I want to receive it as "xyz" field name. Requirement is somewhat similar to "projection" functionality of mongoDB (i.e. include->as method).

Desired response:

 "hits" : [
      {
        "_index" : "testpoc",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "csp" : 19.0,
          "pld" : "PDyfJ3MypQYK4MA2222",
          "tms" : "2022-11-29T11:15:02+0000"
        }
      }]

What should I add in query or search request to get the required response?

I read about the aliasing in ES, but for that I've to change the index mapping (in my project it's not an option), I did try ES scripts also, but it is somewhat similar to processing the response in java code that can be done on project side too.

I want to know if there is anything that can be used to map or change the retrieved fields names of ES search response?

2

Elasticsearch will return the JSON stored (or selected fields) but I do not think there is any built in support for rewriting data. This is as far as I know something you need to handle client side.

1 Like
3

Christian is correct, there's no way to do this in Elasticsearch.

4

Thanks @Christian_Dahlqvist @warkolm. I will make the required changes in client side.

5

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