Tutorial

This document describes how to use Groonga-HTTP step by step. If you don't install Groonga-HTTP yet, install Groonga-HTTP before you read this document.

Full text search

• How to connect to Groonga HTTP server.
• How to execute full text search with Groonga.

How to connect to Groonga HTTP server

We create Groonga::HTTP object with the new() method::

use Groonga::HTTP;

my $groonga = Groonga::HTTP->new;

the new() method has two arguments as below.

• host: We can specify the IP address or host name of Groonga HTTP server. The default value of host is 127.0.0.1.
• port: We can specify the port of Groonga HTTP server. The default value of port is 10041.

If we want to specify host and port except the default value, we create Groonga::HTTP object as below::

use Groonga::HTTP;

my $groonga = Groonga::HTTP->new(
  host => '192.0.2.0',
  port => '20041');

We call groonga_version() method with $groonga to confirm whether we connect to Groonga HTTP server normally or not::

use Groonga::HTTP;

my $groonga = Groonga::HTTP->new;
print $groonga->groonga_version();

If we connect to Groonga HTTP server normally, the groonga_version() method returns the version of Groonga.

Drilldown

drilldown enables us to get the number of records which belongs to specific the value of column at once.

Example:

use Groonga::HTTP;

my $groonga = Groonga::HTTP->new;

my @result = $groonga->select(
   table => 'Entries',
   output_columns => '_key,tag',
   drilldown => 'tag'
);

#Result
#[
#  [
#    "Hello",
#    1
#  ],
#  [
#    "Groonga",
#    2
#  ],
#  [
#    "Senna",
#    2
#  ]
#]

The above example shows the following.

• The number of records that the value of tag is "Hello" is 1.
• The number of records that the value of tag is "Groonga" is 2.
• The number of records that the value of tag is "Senna" is 2.

Filter of the result of drilldown

We can filter the result of drilldown by drilldown_filter. We specify the filter condition against the drilled down result into drilldown_filter.

Here is an example to suppress tags that are occurred only once.

Example:

use Groonga::HTTP;

my $groonga = Groonga::HTTP->new;

my @result = $groonga->select(
   table => 'Entries',
   output_columns => '_key,tag',
   drilldown => 'tag',
   drilldown_filter => '_nsubrecs > 1'
);

#Result
#[
#  [
#    "Groonga",
#    2
#  ],
#  [
#    "Senna",
#    2
#  ]
#]

Sort of result

Groonga-HTTP can sort search results by a specific value of a column. The default of the order is ascending order. We can reverse the order by the prefix of "-".

Example:

use Groonga::HTTP;

my $groonga = Groonga::HTTP->new;

# Ascending order

my @result = $groonga->select(
  table => 'Site',
  columns => 'title',
  query => 'six OR seven',
  output_columns => '_id, title',
  sort_keys => 'id'
);

# Result
#    [
#      [
#        6,
#        'test test test test record six.'
#      ],
#      [
#        7,
#        'test test test record seven.'
#      ],
#    ],

# Descending order

my @result = $groonga->select(
  table => 'Site',
  columns => 'title',
  query => 'six OR seven',
  output_columns => '_id, title',
  sort_keys => '-id'
);

# Result
#    [
#      [
#        7,
#        'test test test record seven.'
#      ],
#      [
#        6,
#        'test test test test record six.'
#      ],
#    ],

Set weight to the column

Groonga-HTTP can set the weight to a column. We adjust the value of score by this feature.

For example, the weight of the content column is twice in the following example. This weight allocation means content column value is more important rather than _key column value.

Example:

my @result = $groonga->select(
   table => 'Entries',
   match_columns => '_key || content * 2',
   query => 'groonga',
   output_columns => '_key,content,_score'
);

# Result
# [
#   [
#     "Groonga",
#     "I started to use Groonga. It's very fast!",
#     3,
#   ]
# ],