61 lines
1.8 KiB
Plaintext
61 lines
1.8 KiB
Plaintext
[[search-request-script-fields]]
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=== Script Fields
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Allows to return a <<modules-scripting,script
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evaluation>> (based on different fields) for each hit, for example:
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[source,js]
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--------------------------------------------------
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{
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"query" : {
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...
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},
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"script_fields" : {
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"test1" : {
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"script" : "doc['my_field_name'].value * 2"
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},
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"test2" : {
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"script" : "doc['my_field_name'].value * factor",
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"params" : {
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"factor" : 2.0
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}
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}
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}
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}
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--------------------------------------------------
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Script fields can work on fields that are not stored (`my_field_name` in
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the above case), and allow to return custom values to be returned (the
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evaluated value of the script).
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Script fields can also access the actual `_source` document indexed and
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extract specific elements to be returned from it (can be an "object"
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type). Here is an example:
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[source,js]
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--------------------------------------------------
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{
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"query" : {
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...
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},
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"script_fields" : {
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"test1" : {
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"script" : "_source.obj1.obj2"
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}
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}
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}
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--------------------------------------------------
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Note the `_source` keyword here to navigate the json-like model.
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It's important to understand the difference between
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`doc['my_field'].value` and `_source.my_field`. The first, using the doc
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keyword, will cause the terms for that field to be loaded to memory
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(cached), which will result in faster execution, but more memory
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consumption. Also, the `doc[...]` notation only allows for simple valued
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fields (can't return a json object from it) and make sense only on
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non-analyzed or single term based fields.
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The `_source` on the other hand causes the source to be loaded, parsed,
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and then only the relevant part of the json is returned.
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