5.5.3. `mroonga_highlight_html()`#

Added in version 7.05.

5.5.3.1. Summary#

mroonga_highlight_html() highlights the specified keywords in target text. It surrounds each keyword with <span class="keyword">...</span> and special characters in HTML such as < and > are escaped. You can use the result as is safely in HTML.

5.5.3.2. Syntax#

mroonga_highlight_html() has required parameter and optional parameter:

mroonga_highlight_html(text, query AS query)
mroonga_highlight_html(text, query AS query, open_tag AS open_tag)
mroonga_highlight_html(text, query AS query, close_tag AS close_tag)
mroonga_highlight_html(text, query AS query, open_tag AS open_tag, close_tag AS close_tag)

mroonga_highlight_html(text, keyword1, ..., keywordN)
mroonga_highlight_html(text, keyword1, ..., keywordN, open_tag AS open_tag)
mroonga_highlight_html(text, keyword1, ..., keywordN, open_tag AS close_tag)
mroonga_highlight_html(text, keyword1, ..., keywordN, open_tag AS open_tag, close_tag AS close_tag)

AS query is very important. You must specify it to extract keywords from query.

open_tag and close_tag are optional. You can specify a tag for highlighting.

5.5.3.3. Usage#

Here is a sample to highlight keywords “mroonga” and “groonga” in target text by query “mroonga OR groonga”. You must specify AS query:

SELECT mroonga_highlight_html('Mroonga is the Groonga based storage engine.',
                              'mroonga OR groonga' AS query) AS highlighted;

Here is the result of the execution example:

+--------------------------------------------------------------------------------------------------------+
| highlighted                                                                                            |
+--------------------------------------------------------------------------------------------------------+
| <span class="keyword">Mroonga</span> is the <span class="keyword">Groonga</span> based storage engine. |
+--------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Here is a sample to highlight keywords “mroonga” and “groonga” in target text by keywords “mroonga” and “groonga”:

SELECT mroonga_highlight_html('Mroonga is the Groonga based storage engine.',
                              'mroonga', 'groonga') AS highlighted;

Here is the result of the execution example:

+--------------------------------------------------------------------------------------------------------+
| highlighted                                                                                            |
+--------------------------------------------------------------------------------------------------------+
| <span class="keyword">Mroonga</span> is the <span class="keyword">Groonga</span> based storage engine. |
+--------------------------------------------------------------------------------------------------------+

5.5.3.4. Parameters#

5.5.3.4.1. Required parameters#

There is one required parameter.

5.5.3.4.1.1. `text`#

The column name of string or string value to be highlighted.

5.5.3.4.2. Optional parameters#

There are some optional parameters.

5.5.3.4.2.1. `query`#

Specify query in Groonga’s query syntax.

You must specify AS query to extract keywords from query like the following:

SELECT mroonga_highlight_html('...', 'mroonga OR groonga' AS query);

5.5.3.4.2.2. `keyword`#

Specify 0 or more keywords to be highlighted.

5.5.3.4.2.3. `open_tag`#

Specify an open tag for highlighting.

You must specify AS open_tag to specify this parameter like the following.

SELECT mroonga_highlight_html('Mroonga is the Groonga based storage engine.', 'groonga',
                              '<span class="my-class">' AS open_tag) AS highlighted;

-- +----------------------------------------------------------------------------+
-- | highlighted                                                                |
-- +----------------------------------------------------------------------------+
-- | Mroonga is the <span class="my-class">Groonga</span> based storage engine. |
-- +----------------------------------------------------------------------------+

The default value is <span class="keyword">.

5.5.3.4.2.4. `close_tag`#

Specify a close tag for highlighting.

You must specify AS close_tag to specify this parameter like the following.

SELECT mroonga_highlight_html('Mroonga is the Groonga based storage engine.', 'groonga',
                              '<mark>' AS open_tag, '</mark>' AS close_tag) AS highlighted;

-- +-----------------------------------------------------------+
-- | highlighted                                               |
-- +-----------------------------------------------------------+
-- | Mroonga is the <mark>Groonga</mark> based storage engine. |
-- +-----------------------------------------------------------+

The default value is </span>.

5.5.3.5. Return value#

It returns highlighted HTML. If optional parameter is not given, it only escapes special characters in HTML such as <, > in text.

5.5.3. mroonga_highlight_html()#