Caution
This feature is experimental. API will be changed.
highlight_html tags target text. It can use to highlight the search keywords. The tagged text are prepared for embedding HTML. Special characters such as < and > are escapsed as < and >. Keyword is surrounded with <span class="keyword"> and </span>. For example, a tagged text of I am a groonga user. <3 for keyword groonga is I am a <span class="keyword">groonga</span> user. <3.
Here are a schema definition and sample data to show usage.
Execution example:
table_create Entries TABLE_NO_KEY
# [[0,1407692435.35498,0.0364797115325928],true]
column_create Entries body COLUMN_SCALAR ShortText
# [[0,1407692435.39156,0.0256640911102295],true]
table_create Terms TABLE_PAT_KEY ShortText --default_tokenizer TokenBigram --normalizer NormalizerAuto
# [[0,1407692435.423,0.0274741649627686],true]
column_create Terms document_index COLUMN_INDEX|WITH_POSITION Entries body
# [[0,1407692435.45051,0.0534985065460205],true]
load --table Entries
[
{"body": "Mroonga is a MySQL storage engine based on Groonga. <b>Rroonga</b> is a Ruby binding of Groonga."}
]
# [[0,1407692435.50406,0.378907442092896],1]
highlight_html can be used in only --output_columns in select.
highlight_html requires Groonga 4.0.5 or later.
highlight_html requires コマンドバージョン 2 or later.
You also need to specify --query and/or --filter. Keywords are extracted from --query and --filter arguments.
The following example uses --query "groonga mysql". In this case, groonga and mysql are used as keywords.
Execution example:
select Entries --output_columns --match_columns body --query 'groonga mysql' --output_columns 'highlight_html(body)' --command_version 2
# [
# [
# 0,
# 1407692444.86092,
# 0.00188779830932617
# ],
# [
# [
# [
# 1
# ],
# [
# [
# "highlight_html",
# "null"
# ]
# ],
# [
# "Mroonga is a <span class=\"keyword\">MySQL</span> storage engine based on <span class=\"keyword\">Groonga</span>. <b>Rroonga</b> is a Ruby binding of <span class=\"keyword\">Groonga</span>."
# ]
# ]
# ]
# ]
The text are scanned by the keywords for tagging after they are normalized by NormalizerAuto normalizer.
--query "groonga mysql" matches to only the first record's body. highlight_html(body) surrounds the keywords groonga or mysql contained in the text with <span class="keyword"> and </span>.
You can specify string literal instead of column.
Execution example:
select Entries --output_columns 'highlight_html("Groonga is very fast fulltext search engine.")' --command_version 2 --match_columns body --query "groonga"
# [
# [
# 0,
# 1407693081.99183,
# 0.000126123428344727
# ],
# [
# [
# [
# 1
# ],
# [
# [
# "highlight_html",
# "null"
# ]
# ],
# [
# "<span class=\"keyword\">Groonga</span> is very fast fulltext search engine."
# ]
# ]
# ]
# ]
There is only one parameter column .
It specifies a column of the table.
highlight_html returns a tagged string or null. If highlight_html can't find any keywords, it returns null.