add cron DB maintenance script (prune unverified accounts)

Does not cover account deletion yet

maintenance.pl

@@ -0,0 +1,54 @@
+#!/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;