59 lines
1.7 KiB
Plaintext
59 lines
1.7 KiB
Plaintext
[[analysis-normalizers]]
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== Normalizers
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Normalizers are similar to analyzers except that they may only emit a single
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token. As a consequence, they do not have a tokenizer and only accept a subset
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of the available char filters and token filters. Only the filters that work on
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a per-character basis are allowed. For instance a lowercasing filter would be
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allowed, but not a stemming filter, which needs to look at the keyword as a
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whole. The current list of filters that can be used in a normalizer is
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following: `arabic_normalization`, `asciifolding`, `bengali_normalization`,
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`cjk_width`, `decimal_digit`, `elision`, `german_normalization`,
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`hindi_normalization`, `indic_normalization`, `lowercase`,
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`persian_normalization`, `scandinavian_folding`, `serbian_normalization`,
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`sorani_normalization`, `uppercase`.
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[float]
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=== Custom normalizers
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Elasticsearch does not ship with built-in normalizers so far, so the only way
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to get one is by building a custom one. Custom normalizers take a list of char
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<<analysis-charfilters, character filters>> and a list of
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<<analysis-tokenfilters,token filters>>.
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[source,js]
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--------------------------------
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PUT index
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{
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"settings": {
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"analysis": {
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"char_filter": {
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"quote": {
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"type": "mapping",
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"mappings": [
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"« => \"",
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"» => \""
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]
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}
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},
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"normalizer": {
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"my_normalizer": {
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"type": "custom",
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"char_filter": ["quote"],
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"filter": ["lowercase", "asciifolding"]
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}
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}
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}
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},
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"mappings": {
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"properties": {
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"foo": {
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"type": "keyword",
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"normalizer": "my_normalizer"
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}
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}
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}
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}
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--------------------------------
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// CONSOLE
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