Koha/Z3950Responder/GenericSession.pm

   1 #!/usr/bin/perl
   2
   3 package Koha::Z3950Responder::GenericSession;
   4
   5 # Copyright The National Library of Finland 2018
   6 #
   7 # This file is part of Koha.
   8 #
   9 # Koha is free software; you can redistribute it and/or modify it
  10 # under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 3 of the License, or
  12 # (at your option) any later version.
  13 #
  14 # Koha is distributed in the hope that it will be useful, but
  15 # WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License
  20 # along with Koha; if not, see <http://www.gnu.org/licenses>.
  21
  22 use Modern::Perl;
  23
  24 use base qw( Koha::Z3950Responder::Session );
  25
  26 use Koha::Logger;
  27 use Koha::SearchEngine::Search;
  28 use Koha::SearchEngine::QueryBuilder;
  29 use Koha::Z3950Responder::RPN;
  30
  31 =head1 NAME
  32
  33 Koha::Z3950Responder::genericSession
  34
  35 =head1 SYNOPSIS
  36
  37 Backend-agnostic session class that uses C<Koha::Session> as the base class. Utilizes
  38 C<Koha::SearchEngine> for the actual functionality.
  39
  40 =head2 INSTANCE METHODS
  41
  42 =head3 start_search
  43
  44     my ($resultset, $hits) = $self->start_search( $args, $self->{server}->{num_to_prefetch} );
  45
  46 Perform a search using C<Koha::SearchEngine>'s QueryBuilder and Search.
  47
  48 =cut
  49
  50 sub start_search {
  51     my ( $self, $args, $num_to_prefetch ) = @_;
  52
  53     if (!defined $self->{'attribute_mappings'}) {
  54         require YAML;
  55         $self->{'attribute_mappings'} = YAML::LoadFile($self->{server}->{config_dir} . 'attribute_mappings.yaml');
  56     }
  57
  58     my $database = $args->{DATABASES}->[0];
  59     my $builder = Koha::SearchEngine::QueryBuilder->new({ index => $database });
  60     my $searcher = Koha::SearchEngine::Search->new({ index => $database });
  61
  62     my $built_query;
  63     my $query = $args->{RPN}->{'query'}->to_koha($self->{'attribute_mappings'}->{$database});
  64     $self->log_debug("    parsed search: $query");
  65     my @operands = $query;
  66     (undef, $built_query) = $builder->build_query_compat( undef, \@operands, undef, undef, undef, 0);
  67
  68     my ($error, $marcresults, $hits ) = $searcher->simple_search_compat($built_query, 0, $num_to_prefetch);
  69     if (defined $error) {
  70         $self->set_error($args, $self->ERR_SEARCH_FAILED, 'Search failed');
  71         return;
  72     }
  73
  74     my $resultset = {
  75         query => $built_query,
  76         database => $database,
  77         cached_offset => 0,
  78         cached_results => $marcresults,
  79         hits => $hits
  80     };
  81
  82     return ($resultset, $hits);
  83 }
  84
  85 =head3 fetch_record
  86
  87     my $record = $self->fetch_record( $resultset, $args, $offset, $server->{num_to_prefetch} );
  88
  89 Fetch a record from SearchEngine. Caches records in session to avoid too many fetches.
  90
  91 =cut
  92
  93 sub fetch_record {
  94     my ( $self, $resultset, $args, $index, $num_to_prefetch ) = @_;
  95
  96     # Fetch more records if necessary
  97     my $offset = $args->{OFFSET} - 1;
  98     if ($offset < $resultset->{cached_offset} || $offset >= $resultset->{cached_offset} + $num_to_prefetch) {
  99         $self->log_debug("    fetch uncached, fetching $num_to_prefetch records starting at $offset");
 100         my $searcher = Koha::SearchEngine::Search->new({ index => $resultset->{'database'} });
 101         my ($error, $marcresults, $num_hits ) = $searcher->simple_search_compat($resultset->{'query'}, $offset, $num_to_prefetch);
 102         if (defined $error) {
 103             $self->set_error($args, $self->ERR_TEMPORARY_ERROR, 'Fetch failed');
 104             return;
 105         }
 106
 107         $resultset->{cached_offset} = $offset;
 108         $resultset->{cached_results} = $marcresults;
 109     }
 110     return $resultset->{cached_results}[$offset - $resultset->{cached_offset}];
 111 }
 112
 113 1;