added pager for lookup in index

[webpac] / index_DBI.pm

#
# this file implements index functions using DBI
#

package index_DBI;
use strict qw(vars);
use vars qw($Count);
use HTML::Entities;

use DBI;

my %Table;      # index tables which where visited in this run

sub new {
        my $class = shift;
        my $self = {};
        bless($self, $class);

        # FIX: config params
        $self->{dbh} = DBI->connect("DBI:Pg:dbname=webpac","dpavlin","") || die $DBI::errstr;
        # begin transaction
        $self->{dbh}->begin_work || die $self->{dbh}->errstr();

        $Count++;

        return $self;
}

sub delete_and_create {
        my $self = shift;

        my $field = shift;

        $self->{dbh}->commit;
        $self->{dbh}->begin_work;

        my $sql = "select count(*) from $field";
        my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
# FIX: this is not a good way to check if table exists!
        if (1 || $sth->execute() && $sth->fetchrow_hashref) {
                my $sql = "drop table $field";
#               my $sth = $self->{dbh}->do($sql) || die "SQL: $sql ".$self->{dbh}->errstr();
        }
        $sql = "create table $field (
                        item varchar(255),
                        ident varchar(255),
                        count int,
                        ord int,
                        primary key (item,ident)
                )";
#       $sth = $self->{dbh}->do($sql) || die "SQL: $sql ".$self->{dbh}->errstr();
        $sth = $self->{dbh}->do($sql) || warn "SQL: $sql ".$self->{dbh}->errstr();

        $self->{dbh}->commit;
        $self->{dbh}->begin_work;
}

sub insert {
        my $self = shift;

        my $field = shift;
        my $index_data = shift;
        my $ident = shift;      # e.g. library id

        if (! $index_data) {
                print STDERR "\$index->insert() -- no value to insert\n";
                return;
        }

        if (! $Table{$field}) {
                $self->delete_and_create($field);
        }
        $Table{$field}++;

        my $sql = "select item from $field where upper(item)=upper(?)";
        my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
        $sth->execute($index_data) || die "sql: $sql; ".$self->{dbh}->errstr();
        if (! $sth->fetchrow_hashref) {
                my $sql = "insert into $field (item,ident,count) values (?,?,?)";
                my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
                $sth->execute($index_data,$ident,1) || die "sql: $sql; ".$self->{dbh}->errstr();
#print stderr "in index: $index_data\n";
        } else {
                my $sql = "update $field set count = count + 1 where item = ? and ident = ?";
                my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
                $sth->execute($index_data,$ident) || die "sql: $sql; ".$self->{dbh}->errstr();
        }
}

sub check {
        my $self = shift;

        my $field = shift;

        my $sql = "select count(*) from $field";

        my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
        $sth->execute() || die "sql: $sql; ".$self->{dbh}->errstr();

        my ($total) = $sth->fetchrow_array();

        return $total;
}


sub fetch {
        my $self = shift;

        my $field = shift;
        my $what = shift || 'item';     # 'item,ident'
        my $where = shift;

        my $from_ord = shift || 0;
        my $rows = shift || 10;

        my @sql_args;

        my $sql = "select $what from $field";

        if ($where) {
                my $sql2 = " select ord from $field where upper($what) like upper(?)||'%'";
                my $sth = $self->{dbh}->prepare($sql2) || die "sql2: $sql2; ".$self->{dbh}->errstr();

                $sth->execute($where) || die "sql2: $sql2; ".$self->{dbh}->errstr();
                if (my $row = $sth->fetchrow_hashref) {
                        $from_ord += $row->{ord};
                }
        }
        $sql .= " order by ord limit $rows offset $from_ord";

        my $sth = $self->{dbh}->prepare($sql) || die "prepare: $sql; ".$self->{dbh}->errstr();
        $sth->execute() || die "execute: $sql; ".$self->{dbh}->errstr();
        my @arr;
        while (my $row = $sth->fetchrow_hashref) {
                $row->{item} = HTML::Entities::encode($row->{item});
                push @arr,$row;
        }
        return @arr;
}

sub close {
        my $self = shift;


        # re-create ord column (sorted order) in table
        sub create_ord {

                my $table = shift;

                $self->{dbh}->begin_work || die $self->{dbh}->errstr();

                my $sql = "select oid from $table order by item";
                my $sth = $self->{dbh}->prepare($sql) || die "sql: $sql; ".$self->{dbh}->errstr();
                $sql = "update $table set ord=? where oid=?";
                my $sth_update = $self->{dbh}->prepare($sql) || die "sql: $sql; ".$self->{dbh}->errstr();
                $sth->execute() || die "sql: $sql; ".$self->{dbh}->errstr();
                my $ord = 1;
                while (my $row = $sth->fetchrow_hashref) {
                        $sth_update->execute($ord++,$row->{oid});
                }

                $self->{dbh}->commit || die $self->{dbh}->errstr();
        }
        #--- end of sub

        if ($self->{dbh}) {

                # commit
                $self->{dbh}->commit || die $self->{dbh}->errstr();

                foreach my $table (keys %Table) {
# FIX
print STDERR "creating ord for $table...\n";
                        create_ord($table);
                }

                $self->{dbh}->disconnect;
                undef $self->{dbh};
        }
}

END {
        $Count--;
        print STDERR "index_DBI fatal error: \$index->close() not called... $Count references left!\n" if ($Count > 0);
        # FIX: debug output
#       print STDERR "usage\ttable\n";
#       foreach (keys %Table) {
#               print STDERR $Table{$_},"\t$_\n";
#       }
}

1;