-
Notifications
You must be signed in to change notification settings - Fork 504
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Add Ascii folding token filter (#7912)
* adding asciifolding token filter page #7873 Signed-off-by: AntonEliatra <[email protected]> * updating the naming Signed-off-by: AntonEliatra <[email protected]> * updating as per PR comments Signed-off-by: AntonEliatra <[email protected]> * updating the heading Signed-off-by: AntonEliatra <[email protected]> * Updating details as per comments Signed-off-by: AntonEliatra <[email protected]> * Updating details as per comments Signed-off-by: AntonEliatra <[email protected]> * Updating details as per comments Signed-off-by: AntonEliatra <[email protected]> * Apply suggestions from code review Co-authored-by: kolchfa-aws <[email protected]> Signed-off-by: AntonEliatra <[email protected]> * updating as per comments Signed-off-by: Anton Rubin <[email protected]> * Apply suggestions from code review Signed-off-by: kolchfa-aws <[email protected]> * Apply suggestions from code review Co-authored-by: Nathan Bower <[email protected]> Signed-off-by: AntonEliatra <[email protected]> * Update asciifolding.md Signed-off-by: AntonEliatra <[email protected]> --------- Signed-off-by: AntonEliatra <[email protected]> Signed-off-by: Anton Rubin <[email protected]> Signed-off-by: kolchfa-aws <[email protected]> Co-authored-by: kolchfa-aws <[email protected]> Co-authored-by: Nathan Bower <[email protected]>
- Loading branch information
3 people
authored
Sep 11, 2024
1 parent
9b609c6
commit b41858a
Showing
2 changed files
with
136 additions
and
1 deletion.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,135 @@ | ||
| --- | ||
| layout: default | ||
| title: ASCII folding | ||
| parent: Token filters | ||
| nav_order: 20 | ||
| --- | ||
|
|
||
| # ASCII folding token filter | ||
|
|
||
| The `asciifolding` token filter converts non-ASCII characters to their closest ASCII equivalents. For example, *é* becomes *e*, *ü* becomes *u*, and *ñ* becomes *n*. This process is known as *transliteration*. | ||
|
|
||
|
|
||
| The `asciifolding` token filter offers a number of benefits: | ||
|
|
||
| - **Enhanced search flexibility**: Users often omit accents or special characters when entering queries. The `asciifolding` token filter ensures that such queries still return relevant results. | ||
| - **Normalization**: Standardizes the indexing process by ensuring that accented characters are consistently converted to their ASCII equivalents. | ||
| - **Internationalization**: Particularly useful for applications including multiple languages and character sets. | ||
|
|
||
| While the `asciifolding` token filter can simplify searches, it may also lead to the loss of specific information, particularly if the distinction between accented and non-accented characters in the dataset is significant. | ||
| {: .warning} | ||
|
|
||
| ## Parameters | ||
|
|
||
| You can configure the `asciifolding` token filter using the `preserve_original` parameter. Setting this parameter to `true` keeps both the original token and its ASCII-folded version in the token stream. This can be particularly useful when you want to match both the original (with accents) and the normalized (without accents) versions of a term in a search query. Default is `false`. | ||
|
|
||
| ## Example | ||
|
|
||
| The following example request creates a new index named `example_index` and defines an analyzer with the `asciifolding` filter and `preserve_original` parameter set to `true`: | ||
|
|
||
| ```json | ||
| PUT /example_index | ||
| { | ||
| "settings": { | ||
| "analysis": { | ||
| "filter": { | ||
| "custom_ascii_folding": { | ||
| "type": "asciifolding", | ||
| "preserve_original": true | ||
| } | ||
| }, | ||
| "analyzer": { | ||
| "custom_ascii_analyzer": { | ||
| "type": "custom", | ||
| "tokenizer": "standard", | ||
| "filter": [ | ||
| "lowercase", | ||
| "custom_ascii_folding" | ||
| ] | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
| ``` | ||
| {% include copy-curl.html %} | ||
|
|
||
| ## Generated tokens | ||
|
|
||
| Use the following request to examine the tokens generated using the analyzer: | ||
|
|
||
| ```json | ||
| POST /example_index/_analyze | ||
| { | ||
| "analyzer": "custom_ascii_analyzer", | ||
| "text": "Résumé café naïve coördinate" | ||
| } | ||
| ``` | ||
| {% include copy-curl.html %} | ||
|
|
||
| The response contains the generated tokens: | ||
|
|
||
| ```json | ||
| { | ||
| "tokens": [ | ||
| { | ||
| "token": "resume", | ||
| "start_offset": 0, | ||
| "end_offset": 6, | ||
| "type": "<ALPHANUM>", | ||
| "position": 0 | ||
| }, | ||
| { | ||
| "token": "résumé", | ||
| "start_offset": 0, | ||
| "end_offset": 6, | ||
| "type": "<ALPHANUM>", | ||
| "position": 0 | ||
| }, | ||
| { | ||
| "token": "cafe", | ||
| "start_offset": 7, | ||
| "end_offset": 11, | ||
| "type": "<ALPHANUM>", | ||
| "position": 1 | ||
| }, | ||
| { | ||
| "token": "café", | ||
| "start_offset": 7, | ||
| "end_offset": 11, | ||
| "type": "<ALPHANUM>", | ||
| "position": 1 | ||
| }, | ||
| { | ||
| "token": "naive", | ||
| "start_offset": 12, | ||
| "end_offset": 17, | ||
| "type": "<ALPHANUM>", | ||
| "position": 2 | ||
| }, | ||
| { | ||
| "token": "naïve", | ||
| "start_offset": 12, | ||
| "end_offset": 17, | ||
| "type": "<ALPHANUM>", | ||
| "position": 2 | ||
| }, | ||
| { | ||
| "token": "coordinate", | ||
| "start_offset": 18, | ||
| "end_offset": 28, | ||
| "type": "<ALPHANUM>", | ||
| "position": 3 | ||
| }, | ||
| { | ||
| "token": "coördinate", | ||
| "start_offset": 18, | ||
| "end_offset": 28, | ||
| "type": "<ALPHANUM>", | ||
| "position": 3 | ||
| } | ||
| ] | ||
| } | ||
| ``` | ||
|
|
||
|
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters