7.15.9. highlight#
New in version 6.0.0.
7.15.9.1. Summary#
highlight tags target text. It can use to highlight the search
keyword. It can specify use/not use HTML escape, the normalizer name and
change the tag for each keyword.
7.15.9.2. Syntax#
highlight has required parameter and optional parameter:
highlight(column,
keyword1, open_tag1, close_tag1,
...
[keywordN, open_tagN, close_tagN],
[{"option": "value of option"}])
7.15.9.3. Usage#
Here are a schema definition and sample data to show usage.
Execution example:
table_create Entries TABLE_NO_KEY
# [[0,1337566253.89858,0.000355720520019531],true]
column_create Entries body COLUMN_SCALAR ShortText
# [[0,1337566253.89858,0.000355720520019531],true]
table_create Terms TABLE_PAT_KEY ShortText --default_tokenizer TokenBigram --normalizer NormalizerAuto
# [[0,1337566253.89858,0.000355720520019531],true]
column_create Terms document_index COLUMN_INDEX|WITH_POSITION Entries body
# [[0,1337566253.89858,0.000355720520019531],true]
load --table Entries
[
{"body": "Mroonga is a ＭｙＳＱＬ storage engine based on Groonga. <b>Rroonga</b> is a Ruby binding of Groonga."}
]
# [[0,1337566253.89858,0.000355720520019531],1]
highlight can be used in only --output_columns in
select before version 10.0.6 (exclusive).
However, it can be also used in --output_columns in
logical_select since version 10.0.6.
highlight requires Command version 2
or later.
The following example uses HTML escape and normalzier is NormalizeAuto.
It specifies the tags <span class="keyword1"> and </span> of the
keyword groonga, and the tags <span class="keyword2"> and </span>
of the keyword mysql.
Execution example:
select Entries --output_columns 'highlight(body, "Groonga", "<span class=\\"keyword1\\">", "</span>", "mysql", "<span class=\\"keyword2\\">", "</span>", {"normalizers": "NormalizerAuto", "html_mode": true})' --command_version 2
# [
# [
# 0,
# 1337566253.89858,
# 0.000355720520019531
# ],
# [
# [
# [
# 1
# ],
# [
# [
# "highlight",
# null
# ]
# ],
# [
# "Mroonga is a <span class=\"keyword2\">ＭｙＳＱＬ</span> storage engine based on <span class=\"keyword1\">Groonga</span>. <b>Rroonga</b> is a Ruby binding of <span class=\"keyword1\">Groonga</span>."
# ]
# ]
# ]
# ]
The text are scanned by the keywords for tagging after they are normalized
by NormalizerAuto normalizer.
--query "groonga mysql" matches to the first record’s body.
highight surrounds the keywords groonga contained in the text
with <span class="keyword1"> and </span>, and the keywords mysql
contained in the text with <span class="keyword2"> and </span>.
Special characters such as < and > are escapsed as < and
>.
You can specify string literal instead of column.
Execution example:
select Entries --output_columns 'highlight("Groonga is very fast fulltext search engine.", "Groonga", "<span class=\\"keyword1\\">", "</span>", "mysql", "<span class=\\"keyword2\\">", "</span>", {"normalizers": "NormalizerAuto", "html_mode": true})' --command_version 2 --match_columns body --query "groonga"
# [
# [
# 0,
# 1337566253.89858,
# 0.000355720520019531
# ],
# [
# [
# [
# 1
# ],
# [
# [
# "highlight",
# null
# ]
# ],
# [
# "<span class=\"keyword1\">Groonga</span> is very fast fulltext search engine."
# ]
# ]
# ]
# ]
7.15.9.4. Parameters#
There are multiple required parameters and multiple optional parameters.
7.15.9.4.1. column#
Specifies a highlight target column.
7.15.9.4.2. keywordN#
Specifies a keyword for tagging. You can specify multiple keywords.
7.15.9.4.3. open_tagN#
Specifies a open tag. You can specify multiple open tags for each keywords.
7.15.9.4.4. close_tagN#
Specifies a close tag. You can specify multiple close tags for each keywords.
7.15.9.4.5. {"default_open_tag": "open_tag"}#
Specifies a open tag.
You can not specify multiple open tags unlike open_tagN parameter.
7.15.9.4.6. {"default_close_tag": "close_tag"}#
Specifies a close tag.
You can not specify multiple close tags unlike close_tagN parameter.
7.15.9.4.7. {"html_escape": true} or {"html_mode": true}#
New in version 13.0.2.
Specifies use or not use HTML escape. If it is true , use HTML escape.
If it is false , not use HTML escape.
7.15.9.4.8. {"normalizer": "Normalizerxxx"}#
Specifies a normalizer name.
7.15.9.4.9. {"normalizers": "Normalizerxxx"}#
New in version 13.0.2.
Specifies a normalizer name. You can specify multiple normalizers.
This option is useful when combining NormalizerTable.
7.15.9.4.10. {"sequential_class_tag_mode": true}#
New in version 13.0.2.
The default value of sequential_class_tag_mode is false.
If sequential_class_tag_mode is true, you can use different style(e.g. background color) for each keywords.
If sequential_class_tag_mode is true, class tags are <mark class="keyword-%d">/<mark> for now.
7.15.9.5. Return value#
highlight returns a tagged string or null. If
highlight can’t find any keywords, it returns null.