NAME

Data::SearchEngine::ElasticSearch - ElasticSearch support for Data::SearchEngine

VERSION

version 0.21

SYNOPSIS

    use Data::SearchEngine::Query;
    use Data::SearchEngine::ElasticSearch;

    my $dse = Data::SearchEngine::ElasticSearch->new(
        servers => [ '127.0.0.1:9200' ]
    );

    my $query = Data::SearchEngine::Query->new(
        index => 'tweets',
        page => 1,
        count => 10,
        order => { _score => { order => 'asc' } },
        type => 'query_string',
        facets => {
            etype => { terms => { field => 'etype' } },
            author_organization_literal => { terms => { field => 'author_organization_literal' } },
            author_literal => { terms => { field => 'author_literal' } },
            source_literal => { terms => { field => 'source_literal' } },
        }
    );

    my $results = $dse->search($query);

DESCRIPTION

Data::SearchEngine::ElasticSearch is a backend for Data::SearchEngine. It aims to generalize the features of ElasticSearch so that application authors are insulated from some of the differences betwene search modules.

IMPLEMENTATION NOTES

This module is opinionated. ElasticSearch's query language and features are powerful and difficult to reign in. Therefore this module has taken some steps to bring things toward a more central feature set.

Incomplete

ElasticSearch's query DSL is large and complex. It is not well suited to abstraction by a library like this one. As such you will almost likely find this abstraction lacking. Expect it to improve as the author uses more of ElasticSearch's features in applications.

Resultes

The _index and _version keys will both be populated in the returned Data::SearchEngine::Item.

Explanations

Setting debug to a true value will cause <explain> to be set when the query is sent to ElasticSearch. You can find the explanation by examining the raw attribute of the Data::SearchEngine::Results object.

Queries

It is expected that if your Data::SearchEngine::Query object has any query set then it must also have a type.

The query is then passed on to ElasticSearch thusly:

    $es->search(
        # ...
        query => { $query->type => $query->query }
        # ...
    );

So if you want to do a query_string query, you would set up your query like this:

    my $query = Data::SearchEngine::Query->new(
        # ...
        type => 'query_string',
        query => { query => 'some query text' }
        # ...
    );

See the documents for ElasticSearch's DLS for more details.

Indexing

ElasticSearch wants an index and type for each Item that is indexed. It is expected that you will populate these values in the item thusly:

  my $item = Data::SearchEngine::Item->new(
    id => $something,
    values => {
        index => 'twitter',
        type => 'tweet',
        # and whatever else
    }
  );
  $dse->add($item);

Filters

If you set multiple filters they will be ANDed together. If you want to change this behavior then you can supply an additional argument to the query method:

  $dse->search($query, 'or');

This defaults to 'and'.

Facets & Filters

If you use facets then any filters will be copied into the facet's facet_filter so that the facets are limited similarly to the results.

ATTRIBUTES

servers

The servers to which we'll be connecting.

transport

The transport to use. Refer to ElasticSearch for more information.

METHODS

add ([ $items ])

Add items to the index. Keep in mind that the Data::SearchEngine::Item should have values set for index and type.

engine

Returns the underlying ElasticSearch implementation.

present ($item)

Returns true if the Data::SearchEngine::Item is present. Uses the item's id.

remove_by_id ($item)

Remove the specified item from the index. Uses the item's id.

search ($query)

Search!

find_by_id ($index, $type, $id)

Find a document by it's unique id.

AUTHOR

Cory G Watson <gphat@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Cold Hard Code, LLC.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.