add cron DB maintenance script (prune unverified accounts)

#!/usr/bin/env perl

use strict;

use warnings;

use 5.020;

use DateTime;

use DBI;

my $dbname = $ENV{TRAVELYNX_DB_FILE} // 'run/travelynx.sqlite';

my $dbh = DBI->connect( "dbi:SQLite:dbname=${dbname}", q{}, q{} );

my $get_unverified_query

  = $dbh->prepare(

qq{select email, registered_at from users where status = 0 and registered_at < ?;}

  );

my $get_pending_query

  = $dbh->prepare(qq{select num_tries from pending_mails where email = ?;});

my $set_pending_query = $dbh->prepare(

	qq{update pending_mails set num_tries = ?, last_try = ? where email = ?;});

my $add_pending_query

  = $dbh->prepare(

	qq{insert into pending_mails (email, num_tries, last_try) values (?, ?, ?);}

  );

my $drop_unverified_query = $dbh->prepare(

	qq{delete from users where status = 0 and registered_at < ?;});

my $now = DateTime->now( time_zone => 'Europe/Berlin' );

my $verification_deadline = $now->subtract( hours => 48 )->epoch;

$dbh->begin_work;

$get_unverified_query->execute($verification_deadline);

while ( my @row = $get_unverified_query->fetchrow_array ) {

	my ( $mail, $reg_date ) = @row;

	if ($mail) {

		$get_pending_query->execute($mail);

		my $rows = $get_pending_query->fetchall_arrayref;

		if ( @{$rows} ) {

			my $num_tries = $rows->[0][0];

			$set_pending_query->execute( $num_tries + 1, $reg_date, $mail );

		}

		else {

			$add_pending_query->execute( $mail, 1, $reg_date );

		}

	}

}

$drop_unverified_query->execute($verification_deadline);

printf( "Pruned %d unverified accounts from database\n",

	$drop_unverified_query->rows );

$dbh->commit;

$dbh->disconnect;