NAME

Catmandu::DirectoryIndex - A base role to store relations between id's and directories

SYNOPSIS

    package MyDirectory;
    use Moo;
    use File::Spec;
    use File:Basename;
    use Path::Tiny qw(path);
    with "Catmandu::DirectoryIndex";
    # translate id to directory
    sub _to_path {
        my ( $self, $id ) = @_;
        File::Spec->catdir( $self->base_dir(), $id );
    }
    sub get {
        my ( $self, $id ) = @_;
        my $path = $self->_to_path( $id );
        is_string( $path ) && -d $path ? { _id => $id, _path => $path } : undef;
    }
    sub add {
        my ( $self, $id ) = @_;
        my $path = $self->_to_path( $id );
        path( $path )->mkpath unless -d $path;
        { _id => $id, _path => $path };
    }
    sub delete {
        my ( $self, $id ) = @_;
        my $path = $self->_to_path( $id );
        if ( is_string( $path ) && -d $path ) {
            path( $path )->remove_tree();
        }
    }
    sub delete_all {
        path( $_[0]->base_dir )->remove_tree({ keep_root => 1 });
    }
    # return a generator that returns list of records, that maps _id and _path
    sub generator {
        my $self = $_[0];
        return sub {
            state $records;
            if ( !defined( $records ) ) {
                $records = [];
                opendir my $dh, $self->base_dir() or die($!);
                while( my $entry = readdir( $dh ) ){
                    if ( -d $entry ) {
                        push @$records, {
                            _id => $entry,
                            _path => File::Spec->catfile( $self->base_dir, $entry )
                        };
                    }
                }
                closedir $dh;
            }
            shift( @$records );
        };
    }
    package main;
    my $p = MyDirectory->new( base_dir => "/tmp" );
    Catmandu->store->bag->each(sub {
        my $r = $_[0];
        my $mapping = $p->get( $r->{_id} ) || $p->add( $r->{_id} );
        say $id . " => " . $mapping->{path};
    });