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WARNING: Version 1.3 of Elasticsearch has passed its EOL date.

This documentation is no longer being maintained and may be removed. If you are running this version, we strongly advise you to upgrade. For the latest information, see the current release documentation.

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Elastic Docs ›Elasticsearch Guide [1.3] ›Mapping

Transform

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IMPORTANT: This documentation is no longer updated. Refer to Elastic's version policy and the latest documentation.

Transform

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Added in 1.3.0.

The document can be transformed before it is indexed by registering a script in the transform element of the mapping. The result of the transform is indexed but the original source is stored in the _source field. Example:

{
    "example" : {
        "transform" : {
            "script" : "if (ctx._source['title']?.startsWith('t')) ctx._source['suggest'] = ctx._source['content']",
            "params" : {
                "variable" : "not used but an example anyway"
            },
            "lang": "groovy"
        },
        "properties": {
           "title": { "type": "string" },
           "content": { "type": "string" },
           "suggest": { "type": "string" }
        }
    }
}

Its also possible to specify multiple transforms:

{
    "example" : {
        "transform" : [
            {"script": "ctx._source['suggest'] = ctx._source['content']"}
            {"script": "ctx._source['foo'] = ctx._source['bar'];"}
        ]
    }
}

Because the result isn’t stored in the source it can’t normally be fetched by source filtering. It can be highlighted if it is marked as stored.

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