Koha/Z3950Responder/GenericSession.pm

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