This is a document for PGroonga 1.X. See PGroonga 2.x document when you're using recent PGroonga.

pgroonga.highlight_html function

Since 1.0.7.

Summary

pgroonga.highlight_html function surrounds the specified keywords in the specified text by <span class="keyword"> and </span>. HTML special characters such as & in the specified text are escaped.

Syntax

Here is the syntax of this function:

text pgroonga.highlight_html(target, ARRAY[keyword1, keyword2, ...])

target is a text to be highlighted. It's text type.

keyword1, keyword2, ... are keywords to be highlighted. They're an array of text type. You must specify one or more keywords.

pgroonga.highlight_html markups the keywords in target. It's type is text type.

The keywords are surrounded with <span class="keyword"> and </span>. <, >, & and " in target is HTML escaped.

Usage

You need to specify at least one keyword:

SELECT pgroonga.highlight_html('PGroonga is a PostgreSQL extension.',
                               ARRAY['PostgreSQL']);
--                           highlight_html                          
-- ------------------------------------------------------------------
--  PGroonga is a <span class="keyword">PostgreSQL</span> extension.
-- (1 row)

You can specify multiple keywords:

SELECT pgroonga.highlight_html('PGroonga is a PostgreSQL extension.',
                               ARRAY['Groonga', 'PostgreSQL']);
--                                         highlight_html                                         
-- -----------------------------------------------------------------------------------------------
--  P<span class="keyword">Groonga</span> is a <span class="keyword">PostgreSQL</span> extension.
-- (1 row)

You can extract keywords from query by pgroonga.query_extract_keywords function:

SELECT pgroonga.highlight_html('PGroonga is a PostgreSQL extension.',
                               pgroonga.query_extract_keywords('Groonga PostgreSQL -extension'));
--                                         highlight_html                                         
-- -----------------------------------------------------------------------------------------------
--  P<span class="keyword">Groonga</span> is a <span class="keyword">PostgreSQL</span> extension.
-- (1 row)

HTML special characters are escaped automatically:

SELECT pgroonga.highlight_html('<p>PGroonga is Groonga & PostgreSQL.</p>',
                               ARRAY['PostgreSQL']);
--                                     highlight_html                                     
-- ---------------------------------------------------------------------------------------
--  &lt;p&gt;PGroonga is Groonga &amp; <span class="keyword">PostgreSQL</span>.&lt;/p&gt;
-- (1 row)

Characters are normalized:

SELECT pgroonga.highlight_html('PGroonga + pglogical = replicatable!',
                               ARRAY['Pg']);
                                         highlight_html                                         
------------------------------------------------------------------------------------------------
 <span class="keyword">PG</span>roonga + <span class="keyword">pg</span>logical = replicatable!
(1 row)

Multibyte characters are also supported:

SELECT pgroonga.highlight_html('10㌖先にある100ｷﾛグラムの米',
                               ARRAY['キロ']);
--                                     highlight_html                                     
-- ---------------------------------------------------------------------------------------
--  10<span class="keyword">㌖</span>先にある100<span class="keyword">ｷﾛ</span>グラムの米
-- (1 row)

See also