Check if id exist in array field or not using script_fields

Question

i like to get a script field if a specific value exist in a array .

Here is my mapping -

"mappings": {
    "properties": {
        "field1": {
            "type": "text",
        },
        "field2": {
            "type": "text",
        },
    }
}

Here is my example documents -

{
    "field1": "hello 1",
    "field2": ["id1","id3"]
}

{
    "field1": "hello 2",
    "field2": ["id2","id3"]
}
{
    "field1": "hello 3",

}
{
    "field1": "mobile 1",
    "field2": ["id1","id4"]
}

Here is my search query -

{
    "query": {
        "match" : {
            "title": "hello"
        }
    },
    "script_fields":{
        "testField2":{
            "script": {
                "source":"doc['field2'].value ==  params.id ? true : false",
                "params": {
                    "id": "id1"
                }
            }
        }
    }

}

what i want to achieve is to get all those document which has "hello" in their title and add a custom field (testField2) in every doc . the value of that custom field would be True if "field2" contain a specific id ("id1") else False

Jozef - Spatialized.io · Accepted Answer · 2021-03-07 11:59:41Z

1

If field2 is only mapped as text, you won't be able to use its field values (via doc['field2'].value). You can only use its _source:

POST your-index/_search
{
  "query": {
    "match": {
      "field1": "hello"
    }
  },
  "script_fields": {
    "testField2": {
      "script": {
        "source": "params._source.containsKey('field2') ? params._source.field2.contains(params.id) : false",
        "params": {
          "id": "id1"
        }
      }
    }
  }
}

Note that accessing _source is not as efficient as using the doc values -- so in short, you were using the right strategy but with the wrong mapping.

In order to be able to access the doc values, either use the keyword data type or set the fielddata parameter on your existing text field to true. I'm going to go with the keyword here:

DELETE your-index

PUT your-index
{
  "mappings": {
    "properties": {
      "field1": {
        "type": "text"
      },
      "field2": {
        "type": "keyword"     <--
      }
    }
  }
}

After reindexing (which is required after a "mapping breaking change") you can then call:

POST your-index/_search
{
  "query": {
    "match": {
      "field1": "hello"
    }
  },
  "script_fields": {
    "testField2": {
      "script": {
        "source": "doc['field2'].size() != 0 ? doc['field2'].asList().contains(params.id) : false",
        "params": {
          "id": "id1"
        }
      }
    }
  }
}

Finally, notice the .asList() method. It's needed to convert the doc values which are an instance of the class ScriptDocValues.Strings to a consumable ArrayList on which you can then call the conventional .contains() method.

answered Mar 7, 2021 at 11:59

Jozef - Spatialized.io

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3 Comments

Aninda Over a year ago

thank you very much, it worked . previously i tried with keyword & nested mapping, but it wasn't working, probably because i was not using .asList() and .contain() method

codeedoc Over a year ago

@ Joe - ElasticsearchBook.com I just encountered you answer and it works! But I am confused with why size() method works on checking if the field exists. I suspect it has to do with internally how the field is mapped. But I couldn't find any resources on this.

Jozef - Spatialized.io Over a year ago

@codeedoc yea it's an internal method on the doc value instance.

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